range-diff: also show the diff between patches

Just like tbdiff, we now show the diff between matching patches. This is
a "diff of two diffs", so it can be a bit daunting to read for the
beginner.

An alternative would be to display an interdiff, i.e. the hypothetical
diff which is the result of first reverting the old diff and then
applying the new diff.

Especially when rebasing frequently, an interdiff is often not feasible,
though: if the old diff cannot be applied in reverse (due to a moving
upstream), an interdiff can simply not be inferred.

This commit brings `range-diff` closer to feature parity with regard
to tbdiff.

To make `git range-diff` respect e.g. color.diff.* settings, we have
to adjust git_branch_config() accordingly.

Note: while we now parse diff options such as --color, the effect is not
yet the same as in tbdiff, where also the commit pairs would be colored.
This is left for a later commit.

Note also: while tbdiff accepts the `--no-patches` option to suppress
these diffs between patches, we prefer the `-s` (or `--no-patch`) option
that is automatically supported via our use of diff_opt_parse().

And finally note: to support diff options, we have to call
`parse_options()` such that it keeps unknown options, and then loop over
those and let `diff_opt_parse()` handle them. After that loop, we have
to call `parse_options()` again, to make sure that no unknown options
are left.

Helped-by: Thomas Gummerer <t.gummerer@gmail.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

range-diff: improve the order of the shown commits

This patch lets `git range-diff` use the same order as tbdiff.

The idea is simple: for left-to-right readers, it is natural to assume
that the `git range-diff` is performed between an older vs a newer
version of the branch. As such, the user is probably more interested in
the question "where did this come from?" rather than "where did that one
go?".

To that end, we list the commits in the order of the second commit range
("the newer version"), inserting the unmatched commits of the first
commit range as soon as all their predecessors have been shown.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

range-diff: first rudimentary implementation

At this stage, `git range-diff` can determine corresponding commits
of two related commit ranges. This makes use of the recently introduced
implementation of the linear assignment algorithm.

The core of this patch is a straight port of the ideas of tbdiff, the
apparently dormant project at https://github.com/trast/tbdiff.

The output does not at all match `tbdiff`'s output yet, as this patch
really concentrates on getting the patch matching part right.

Note: due to differences in the diff algorithm (`tbdiff` uses the Python
module `difflib`, Git uses its xdiff fork), the cost matrix calculated
by `range-diff` is different (but very similar) to the one calculated
by `tbdiff`. Therefore, it is possible that they find different matching
commits in corner cases (e.g. when a patch was split into two patches of
roughly equal length).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Introduce `range-diff` to compare iterations of a topic branch

This command does not do a whole lot so far, apart from showing a usage
that is oddly similar to that of `git tbdiff`. And for a good reason:
the next commits will turn `range-branch` into a full-blown replacement
for `tbdiff`.

At this point, we ignore tbdiff's color options, as they will all be
implemented later using diff_options.

Since f318d739159 (generate-cmds.sh: export all commands to
command-list.h, 2018-05-10), every new command *requires* a man page to
build right away, so let's also add a blank man page, too.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

linear-assignment: a function to solve least-cost assignment problems

The problem solved by the code introduced in this commit goes like this:
given two sets of items, and a cost matrix which says how much it
"costs" to assign any given item of the first set to any given item of
the second, assign all items (except when the sets have different size)
in the cheapest way.

We use the Jonker-Volgenant algorithm to solve the assignment problem to
answer questions such as: given two different versions of a topic branch
(or iterations of a patch series), what is the best pairing of
commits/patches between the different versions?

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t5552: suppress upload-pack trace output

The t5552 test script uses GIT_TRACE_PACKET to monitor what
git-fetch sends and receives. However, because we're
accessing a local repository, the child upload-pack also
sends trace output to the same file.

On Linux, this works out OK. We open the trace file with
O_APPEND, so all writes are atomically positioned at the end
of the file. No data can be overwritten or omitted. And
since we prepare our small writes in a strbuf and write them
with a single write(), we should see each line as an atomic
unit. The order of lines between the two processes is
undefined, but the test script greps only for "fetch>" or
"fetch<" lines. So under Linux, the test results are
deterministic.

The test fails intermittently on Windows, however,
reportedly even overwriting bits of the output file (i.e.,
O_APPEND does not seem to give us an atomic position+write).

Since the test only cares about the trace output from fetch,
we can just disable the output from upload-pack. That
doesn't solve the greater question of O_APPEND/trace issues
under Windows, but it easily fixes the flakiness from this
test.

Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gpg-interface: propagate exit status from gpg back to the callers

When gpg-interface API unified support for signature verification
codepaths for signed tags and signed commits in mid 2015 at around
v2.6.0-rc0~114, we accidentally loosened the GPG signature
verification.

Before that change, signed commits were verified by looking for
"G"ood signature from GPG, while ignoring the exit status of "gpg
--verify" process, while signed tags were verified by simply passing
the exit status of "gpg --verify" through. The unified code we
currently have ignores the exit status of "gpg --verify" and returns
successful verification when the signature matches an unexpired key
regardless of the trust placed on the key (i.e. in addition to "G"ood
ones, we accept "U"ntrusted ones).

Make these commands signal failure with their exit status when
underlying "gpg --verify" (or the custom command specified by
"gpg.program" configuration variable) does so. This essentially
changes their behaviour in a backward incompatible way to reject
signatures that have been made with untrusted keys even if they
correctly verify, as that is how "gpg --verify" behaves.

Note that the code still overrides a zero exit status obtained from
"gpg" (or gpg.program) if the output does not say the signature is
good or computes correctly but made with untrusted keys, to catch
a poorly written wrapper around "gpg" the user may give us.

We could exclude "U"ntrusted support from this fallback code, but
that would be making two backward incompatible changes in a single
commit, so let's avoid that for now. A follow-up change could do so
if desired.

Helped-by: Vojtech Myslivec <vojtech.myslivec@nic.cz>
Helped-by: brian m. carlson <sandals@crustytoothpaste.net>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

repack: repack promisor objects if -a or -A is set

Currently, repack does not touch promisor packfiles at all, potentially
causing the performance of repositories that have many such packfiles to
drop. Therefore, repack all promisor objects if invoked with -a or -A.

This is done by an additional invocation of pack-objects on all promisor
objects individually given, which takes care of deduplication and allows
the resulting packfiles to respect flags such as --max-pack-size.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

repack: refactor setup of pack-objects cmd

A subsequent patch will teach repack to run pack-objects with some same
and some different arguments if repacking of promisor objects is
required. Refactor the setup of the pack-objects cmd so that setting up
the arguments common to both is done in a function.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

rebase --exec: make it work with --rebase-merges

The idea of `--exec` is to append an `exec` call after each `pick`.

Since the introduction of fixup!/squash! commits, this idea was extended
to apply to "pick, possibly followed by a fixup/squash chain", i.e. an
exec would not be inserted between a `pick` and any of its corresponding
`fixup` or `squash` lines.

The current implementation uses a dirty trick to achieve that: it
assumes that there are only pick/fixup/squash commands, and then
*inserts* the `exec` lines before any `pick` but the first, and appends
a final one.

With the todo lists generated by `git rebase --rebase-merges`, this
simple implementation shows its problems: it produces the exact wrong
thing when there are `label`, `reset` and `merge` commands.

Let's change the implementation to do exactly what we want: look for
`pick` lines, skip any fixup/squash chains, and then insert the `exec`
line. Lather, rinse, repeat.

Note: we take pains to insert *before* comment lines whenever possible,
as empty commits are represented by commented-out pick lines (and we
want to insert a preceding pick's exec line *before* such a line, not
afterward).

While at it, also add `exec` lines after `merge` commands, because they
are similar in spirit to `pick` commands: they add new commits.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sideband: highlight keywords in remote sideband output

The colorization is controlled with the config setting "color.remote".

Supported keywords are "error", "warning", "hint" and "success". They
are highlighted if they appear at the start of the line, which is
common in error messages, eg.

ERROR: commit is missing Change-Id

The Git push process itself prints lots of non-actionable messages
(eg. bandwidth statistics, object counters for different phases of the
process). This obscures actionable error messages that servers may
send back. Highlighting keywords in the sideband draws more attention
to those messages.

The background for this change is that Gerrit does server-side
processing to create or update code reviews, and actionable error
messages (eg. missing Change-Id) must be communicated back to the user
during the push. User research has shown that new users have trouble
seeing these messages.

The highlighting is done on the client rather than server side, so
servers don't have to grow capabilities to understand terminal escape
codes and terminal state. It also consistent with the current state
where Git is control of the local display (eg. prefixing messages with
"remote: ").

The highlighting can be configured using color.remote.<KEYWORD>
configuration settings. Since the keys are matched case insensitively,
we match the keywords case insensitively too.

Finally, this solution is backwards compatible: many servers already
prefix their messages with "error", and they will benefit from this
change without requiring a server update. By contrast, a server-side
solution would likely require plumbing the TERM variable through the
git protocol, so it would require changes to both server and client.

Helped-by: Duy Nguyen <pclouds@gmail.com>
Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

update-index: there no longer is `apply --index-info`

Back when we removed `git apply --index-info` in 2007, we forgot to
adjust the documentation for update-index that reads its output.

Let's reorder the description of three formats to present the other
two formats that are still generated by git commands before this
format, and stop mentioning `git apply --index-info`.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-update-index.txt: reword possibly confusing example

The following phrase could be interpreted multiple ways:
"To pretend you have a file with mode and sha1 at path"

In particular, I can think of two:
1. Pretend we have some new file, which happens to have a given mode
and sha1
2. Pretend one of the files we are already tracking has a different
mode and sha1 than what it really does

I think people could easily assume either case while reading, but the
example command provided doesn't actually handle the first case, which
caused some minor frustration to at least one user. Modify the example
command so that it correctly handles both cases, and re-order the
wording in a way that makes it more likely folks will assume the first
interpretation. I believe the new example shouldn't pose any obstacles
to those wanting the second interpretation (at worst, they pass an
unnecessary extra flag).

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-config: document accidental multi-line setting in deprecated syntax

The bug was noticed when writing the previous patch; a fix for this bug
is not easy though: If we choose to ignore the case of the subsection
(and revert most of the code of the previous patch, just keeping
s/strncasecmp/strcmp/), then we'd introduce new sections using the
new syntax, such that

--------
[section.subsection]
key = value1
--------

git config section.Subsection.key value2

would result in

--------
[section.subsection]
key = value1
[section.Subsection]
key = value2
--------

which is even more confusing. A proper fix would replace the first
occurrence of 'key'. As the syntax is deprecated, let's prefer to not
spend time on fixing the behavior and just document it instead.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config: fix case sensitive subsection names on writing

A user reported a submodule issue regarding a section mix-up,
but it could be boiled down to the following test case:

$ git init test && cd test
$ git config foo."Bar".key test
$ git config foo."bar".key test
$ tail -n 3 .git/config
[foo "Bar"]
key = test
key = test

Sub sections are case sensitive and we have a test for correctly reading
them. However we do not have a test for writing out config correctly with
case sensitive subsection names, which is why this went unnoticed in
6ae996f2acf (git_config_set: make use of the config parser's event
stream, 2018-04-09)

Unfortunately we have to make a distinction between old style configuration
that looks like

[foo.Bar]
key = test

and the new quoted style as seen above. The old style is documented as
case-agnostic, hence we need to keep 'strncasecmp'; although the
resulting setting for the old style config differs from the configuration.
That will be fixed in a follow up patch.

Reported-by: JP Sugarbroad <jpsugar@google.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t7406: avoid using test_must_fail for commands other than git

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t7406: prefer test_* helper functions to test -[feds]

test -e, test -s, etc. do not provide nice error messages when we hit
test failures, so use the test_* helper functions from
test-lib-functions.sh.

Also, add test_path_exists() to test-lib-function.sh while at it, so
that we don't need to worry whether submodule/.git is a file or a
directory. It currently is a file with contents of the form
gitdir: ../.git/modules/submodule
but it could be changed in the future to be a directory; this test
only really cares that it exists.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t7406: avoid having git commands upstream of a pipe

When a git command is on the left side of a pipe, the pipe will swallow
its exit status, preventing us from detecting failures in said commands.
Restructure the tests to put the output in a temporary file to avoid
this problem.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t7406: simplify by using diff --name-only instead of diff --raw

We can get rid of some quoted tabs and make a few tests slightly easier
to read and edit by just asking for the names of the files modified,
since that's all these tests were interested in anyway.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t7406: fix call that was failing for the wrong reason

A test making use of test_must_fail was failing like this:
fatal: ambiguous argument '|': unknown revision or path not in the working tree.
when the intent was to verify that a specific string was not found
in the output of the git diff command, i.e. that grep returned
non-zero. Fix the test to do that.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

remote-curl: remove spurious period

We should not interrupt. sentences in the middle.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-compat-util.h: fix typo

The words "save" and "safe" are both very wonderful words, each with
their own set of meanings. Let's not confuse them with one another save
on occasion of a pun.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-instaweb: fix apache2 config with apache >= 2.4

The generated apache2 config fails with apache >= 2.4. The error log
states:

AH00136: Server MUST relinquish startup privileges before accepting
connections. Please ensure mod_unixd or other system security
module is loaded.
AH00016: Configuration Failed

Fix this by loading the unixd module. This works with older httpd as
well, so no IfVersion conditional is needed. (Tested with httpd-2.2.15
on CentOS-6.)

Written with assistance of Todd Zullinger <tmz@pobox.com>

Signed-off-by: Sebastian Kisela <skisela@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-instaweb: support Fedora/Red Hat apache module path

On Fedora-derived systems, the apache httpd package installs modules
under /usr/lib{,64}/httpd/modules, depending on whether the system is
32- or 64-bit. A symlink from /etc/httpd/modules is created which
points to the proper module path. Use it to support apache on Fedora,
CentOS, and Red Hat systems.

Written with assistance of Todd Zullinger <tmz@pobox.com> and
Junio C Hamano <gitster@pobox.com>.

Signed-off-by: Sebastian Kisela <skisela@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer: fix quoting in write_author_script

Single quotes should be escaped as \' not \\'. The bad quoting breaks
the interactive version of 'rebase --root' (which is used when there
is no '--onto' even if the user does not specify --interactive) for
authors that contain "'" as sq_dequote() called by read_author_ident()
errors out on the bad quoting.

For other interactive rebases this only affects external scripts that
read the author script and users whose git is upgraded from the shell
version of rebase -i while rebase was stopped when the author contains
"'". This is because the parsing in read_env_script() expected the
broken quoting.

This patch includes code to handle the broken quoting when
git has been upgraded while rebase was stopped. It does this by
detecting the missing "'" at the end of the GIT_AUTHOR_DATE line to see
if it should dequote \\' as "'". Note this is only implemented for
normal picks, not for creating a new root commit (rebase will stop with
an error complaining out bad quoting in that case).

The fallback code has been manually tested by reverting both the quoting
fixes in write_author_script() and the previous fix for the missing "'"
at the end of the GIT_AUTHOR_DATE line and running
t3404-rebase-interactive.sh.

Ideally rebase and am would share the same code for reading and
writing the author script, but this commit just fixes the immediate
bug.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer: handle errors from read_author_ident()

Check for a NULL return value from read_author_ident() that indicates
an error. Previously the NULL author was passed to commit_tree() which
would then fallback to using the default author when creating the new
commit. This changed the date and potentially the author of the commit
which corrupted the author data compared to its expected value.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

doc hash-function-transition: pick SHA-256 as NewHash

From a security perspective, it seems that SHA-256, BLAKE2, SHA3-256,
K12, and so on are all believed to have similar security properties.
All are good options from a security point of view.

SHA-256 has a number of advantages:

* It has been around for a while, is widely used, and is supported by
just about every single crypto library (OpenSSL, mbedTLS, CryptoNG,
SecureTransport, etc).

* When you compare against SHA1DC, most vectorized SHA-256
implementations are indeed faster, even without acceleration.

* If we're doing signatures with OpenPGP (or even, I suppose, CMS),
we're going to be using SHA-2, so it doesn't make sense to have our
security depend on two separate algorithms when either one of them
alone could break the security when we could just depend on one.

So SHA-256 it is. Update the hash-function-transition design doc to
say so.

After this patch, there are no remaining instances of the string
"NewHash", except for an unrelated use from 2008 as a variable name in
t/t9700/test.pl.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: brian m. carlson <sandals@crustytoothpaste.net>
Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Acked-by: Dan Shumow <danshu@microsoft.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t: factor out FUNNYNAMES as shared lazy prereq

A fair number of tests need to check that the filesystem supports file
names including "funny" characters, like newline, tab, and double-quote.
Jonathan Nieder suggested that this be extracted into a lazy prereq in
the top-level `test-lib.sh`. This patch effects that change.

The FUNNYNAMES prereq now uniformly requires support for newlines, tabs,
and double-quotes in filenames. This very slightly decreases the power
of some tests, which might have run previously on a system that supports
(e.g.) newlines and tabs but not double-quotes, but now will not. This
seems to me like an acceptable tradeoff for consistency.

One test (`t/t9902-completion.sh`) defined FUNNYNAMES to further require
the separators \034 through \037, the test for which was implemented
using the Bash-specific $'\034' syntax. I've elected to leave this one
as is, renaming it to FUNNIERNAMES.

After this patch, `git grep 'test_\(set\|lazy\)_prereq.*FUNNYNAMES'` has
only one result.

Signed-off-by: William Chargin <wchargin@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile: add missing dependency for command-list.h

Commit 3ac68a93fd (help: add --config to list all available config -
2018-05-26) makes generate-cmdlist.sh adds a new input source
config.txt but it's not a Makefile dependency. Any changes in
config.txt will not trigger command-list.h regeneration and the config
list in this file becomes outdated. Correct the dependency.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t3430: demonstrate what -r, --autosquash & --exec should do

The --exec option's implementation is not really well-prepared for
--rebase-merges. Demonstrate this.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t4150: fix broken test for am --scissors

Tests for "git am --[no-]scissors" [1] work in the following way:

1. Create files with commit messages
2. Use these files to create expected commits
3. Generate eml file with patch from expected commits
4. Create commits using git am with these eml files
5. Compare these commits with expected

The test for "git am --scissors" is supposed to take an e-mail with a
scissors line and in-body "Subject:" header and demonstrate that the
subject line from the e-mail itself is overridden by the in-body header
and that only text below the scissors line is included in the commit
message of the commit created by the invocation of "git am --scissors".
However, the setup of the test incorrectly uses a commit without the
scissors line and without the in-body header in the commit message,
producing eml file not suitable for testing of "git am --scissors".

This can be checked by intentionally breaking is_scissors_line function
in mailinfo.c, for example, by changing string ">8", which is used by
the test. With such change the test should fail, but does not.

Fix broken test by generating eml file with scissors line and in-body
header "Subject:". Since the two tests for --scissors and --no-scissors
options are there to test cutting or keeping the commit message, update
both tests to change the test file in the same way, which allows us to
generate only one eml file to be passed to git am. To clarify the
intention of the test, give files and tags more explicit names.

[1]: introduced in bf72ac17d (t4150: tests for am --[no-]scissors,
2015-07-19)

Signed-off-by: Andrei Rybak <rybak.a.v@gmail.com>
Reviewed-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pull --rebase=<type>: allow single-letter abbreviations for the type

Git for Windows' original 4aa8b8c8283 (Teach 'git pull' to handle
--rebase=interactive, 2011-10-21) had support for the very convenient
abbreviation

git pull --rebase=i

which was later lost when it was ported to the builtin `git pull`, and
it was not introduced before the patch eventually made it into Git as
f5eb87b98dd (pull: allow interactive rebase with --rebase=interactive,
2016-01-13).

However, it is *really* a useful short hand for the occasional rebasing
pull on branches that do not usually want to be rebased.

So let's reintroduce this convenience, at long last.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

add a script to diff rendered documentation

After making a change to the documentation, it's easy to
forget to check the rendered version to make sure it was
formatted as you intended. And simply doing a diff between
the two built versions is less trivial than you might hope:

- diffing the roff or html output isn't particularly
readable; what we really care about is what the end user
will see

- you have to tweak a few build variables to avoid
spurious differences (e.g., version numbers, build
times)

Let's provide a script that builds and installs the manpages
for two commits, renders the results using "man", and diffs
the result. Since this is time-consuming, we'll also do our
best to avoid repeated work, keeping intermediate results
between runs.

Some of this could probably be made a little less ugly if we
built support into Documentation/Makefile. But by relying
only on "make install-man" working, this script should work
for generating a diff between any two versions, whether they
include this script or not.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config: document git config getter return value

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

config.txt: reorder blame stuff to keep config keys sorted

The color group in config.txt is actually sorted but changes in
sb/blame-color broke this. Reorder color.blame.* and move
blame.coloring back to the rest of blame.* (and reorder that group too
while we're there)

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t3031: update test description to mention desired behavior

This test description looks like it was written with the originally
observed behavior ("causes segfault") rather than the desired and now
current behavior ("does not cause segfault"). Fix it.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

submodule.h: drop extern from function declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

revision.h: drop extern from function declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

repository.h: drop extern from function declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

rerere.h: drop extern from function declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

line-range.h: drop extern from function declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.h: remove extern from function declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diffcore.h: drop extern from function declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

convert.h: drop 'extern' from function declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache-tree.h: drop extern from function declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

blame.h: drop extern on func declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

attr.h: drop extern from function declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

apply.h: drop extern on func declaration

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

color: protect against out-of-bounds reads and writes

want_color_fd() is designed to work only with standard output and
error file descriptors and stores information about each descriptor in
an array. However, it doesn't verify that the passed-in descriptor
lives within that set, which, with a buggy caller, could lead to
access or assignment outside the array bounds.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

parse-options: automatically infer PARSE_OPT_LITERAL_ARGHELP

Parseopt wraps argument help strings in a pair of angular brackets by
default, to tell users that they need to replace it with an actual
value. This is useful in most cases, because most option arguments
are indeed single values of a certain type. The option
PARSE_OPT_LITERAL_ARGHELP needs to be used in option definitions with
arguments that have multiple parts or are literal strings.

Stop adding these angular brackets if special characters are present,
as they indicate that we don't deal with a simple placeholder. This
simplifies the code a bit and makes defining special options slightly
easier.

Remove the flag PARSE_OPT_LITERAL_ARGHELP in the cases where the new
and more cautious handling suffices.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

shortlog: correct option help for -w

Wrap the placeholders in the option help string for -w in pairs of
angular brackets to document that users need to replace them with actual
numbers. Use the flag PARSE_OPT_LITERAL_ARGHELP to prevent parseopt
from adding another pair.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

send-pack: specify --force-with-lease argument help explicitly

Wrap each part of the argument help string in angular brackets to show
that users need to replace them with actual values. Do that explicitly
to balance the pairs nicely in the code and avoid confusing casual
readers. Add the flag PARSE_OPT_LITERAL_ARGHELP to keep parseopt from
adding another pair.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pack-objects: specify --index-version argument help explicitly

Wrap both placeholders in the argument help string in angular brackets
to signal that users needs replace them with some actual value. Use the
flag PARSE_OPT_LITERAL_ARGHELP to prevent parseopt from adding another
pair.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

difftool: remove angular brackets from argument help

Parseopt wraps arguments in a pair of angular brackets by default,
signifying that the user needs to replace it with a value of the
documented type. Remove the pairs from the option definitions to
duplication and confusion.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

add, update-index: fix --chmod argument help

Don't translate the argument specification for --chmod; "+x" and "-x"
are the literal strings that the commands accept.

Separate alternatives using a pipe character instead of a slash, for
consistency.

Use the flag PARSE_OPT_LITERAL_ARGHELP to prevent parseopt from adding a
pair of angular brackets around the argument help string, as that would
wrongly indicate that users need to replace the literal strings with
some kind of value.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

push: use PARSE_OPT_LITERAL_ARGHELP instead of unbalanced brackets

The option help text for the force-with-lease option to "git push"
reads like this:

$ git push -h 2>&1 | grep -e force-with-lease
--force-with-lease[=<refname>:<expect>]

which comes from having N_("refname>:<expect") as the argument help
text in the source code, with an aparent lack of "<" and ">" at both
ends.

It turns out that parse-options machinery takes the whole string and
encloses it inside a pair of "<>", to make it easier for majority
cases that uses a single token placeholder.

The help string was written in a funnily unbalanced way knowing that
the end result would balance out, by somebody who forgot the
presence of PARSE_OPT_LITERAL_ARGHELP, which is the escape hatch
mechanism designed to help such a case. We just should use the
official escape hatch instead.

Because ":<expect>" part can be omitted to ask Git to guess, it may
be more correct to spell it as "<refname>[:<expect>]", but that is
not the focus of this topic.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Fifth batch for 2.19 cycle

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Merge branch 'jt/commit-graph-per-object-store'

The singleton commit-graph in-core instance is made per in-core
repository instance.

* jt/commit-graph-per-object-store:
commit-graph: add repo arg to graph readers
commit-graph: store graph in struct object_store
commit-graph: add free_commit_graph
commit-graph: add missing forward declaration
object-store: add missing include
commit-graph: refactor preparing commit graph

Merge branch 'es/chain-lint-in-subshell'

Look for broken "&&" chains that are hidden in subshell, many of
which have been found and corrected.

* es/chain-lint-in-subshell:
t/chainlint.sed: drop extra spaces from regex character class
t/chainlint: add chainlint "specialized" test cases
t/chainlint: add chainlint "complex" test cases
t/chainlint: add chainlint "cuddled" test cases
t/chainlint: add chainlint "loop" and "conditional" test cases
t/chainlint: add chainlint "nested subshell" test cases
t/chainlint: add chainlint "one-liner" test cases
t/chainlint: add chainlint "whitespace" test cases
t/chainlint: add chainlint "basic" test cases
t/Makefile: add machinery to check correctness of chainlint.sed
t/test-lib: teach --chain-lint to detect broken &&-chains in subshells

Merge branch 'jt/tags-to-promised-blobs-fix'

The lazy clone support had a few places where missing but promised
objects were not correctly tolerated, which have been fixed.

* jt/tags-to-promised-blobs-fix:
tag: don't warn if target is missing but promised
revision: tolerate promised targets of tags

Merge branch 'jt/fetch-negotiator-skipping'

Add a server-side knob to skip commits in exponential/fibbonacci
stride in an attempt to cover wider swath of history with a smaller
number of iterations, potentially accepting a larger packfile
transfer, instead of going back one commit a time during common
ancestor discovery during the "git fetch" transaction.

* jt/fetch-negotiator-skipping:
negotiator/skipping: skip commits during fetch

Merge branch 'jm/send-email-tls-auth-on-batch'

"git send-email" when using in a batched mode that limits the
number of messages sent in a single SMTP session lost the contents
of the variable used to choose between tls/ssl, unable to send the
second and later batches, which has been fixed.

* jm/send-email-tls-auth-on-batch:
send-email: fix tls AUTH when sending batch

Merge branch 'bc/sequencer-export-work-tree-as-well'

"git rebase" started exporting GIT_DIR environment variable and
exposing it to hook scripts when part of it got rewritten in C.
Instead of matching the old scripted Porcelains' behaviour,
compensate by also exporting GIT_WORK_TREE environment as well to
lessen the damage. This can harm existing hooks that want to
operate on different repository, but the current behaviour is
already broken for them anyway.

* bc/sequencer-export-work-tree-as-well:
sequencer: pass absolute GIT_WORK_TREE to exec commands

Merge branch 'en/t7405-recursive-submodule-conflicts'

Tests to cover conflict cases that involve submodules have been
added for merge-recursive.

* en/t7405-recursive-submodule-conflicts:
t7405: verify 'merge --abort' works after submodule/path conflicts
t7405: add a directory/submodule conflict
t7405: add a file/submodule conflict

Merge branch 'en/t6036-merge-recursive-tests'

Tests to cover various conflicting cases have been added for
merge-recursive.

* en/t6036-merge-recursive-tests:
t6036: add a failed conflict detection case: regular files, different modes
t6036: add a failed conflict detection case with conflicting types
t6036: add a failed conflict detection case with submodule add/add
t6036: add a failed conflict detection case with submodule modify/modify
t6036: add a failed conflict detection case with symlink add/add
t6036: add a failed conflict detection case with symlink modify/modify

Merge branch 'en/dirty-merge-fixes'

The recursive merge strategy did not properly ensure there was no
change between HEAD and the index before performing its operation,
which has been corrected.

* en/dirty-merge-fixes:
merge: fix misleading pre-merge check documentation
merge-recursive: enforce rule that index matches head before merging
t6044: add more testcases with staged changes before a merge is invoked
merge-recursive: fix assumption that head tree being merged is HEAD
merge-recursive: make sure when we say we abort that we actually abort
t6044: add a testcase for index matching head, when head doesn't match HEAD
t6044: verify that merges expected to abort actually abort
index_has_changes(): avoid assuming operating on the_index
read-cache.c: move index_has_changes() from merge.c

Merge branch 'js/rebase-merge-octopus'

"git rebase --rebase-merges" mode now handles octopus merges as
well.

* js/rebase-merge-octopus:
rebase --rebase-merges: adjust man page for octopus support
rebase --rebase-merges: add support for octopus merges
merge: allow reading the merge commit message from a file

Merge branch 'tb/grep-only-matching'

"git grep" learned the "--only-matching" option.

* tb/grep-only-matching:
grep.c: teach 'git grep --only-matching'
grep.c: extract show_line_header()

Merge branch 'kg/gc-auto-windows-workaround'

"git gc --auto" opens file descriptors for the packfiles before
spawning "git repack/prune", which would upset Windows that does
not want a process to work on a file that is open by another
process. The issue has been worked around.

* kg/gc-auto-windows-workaround:
gc --auto: release pack files before auto packing

Merge branch 'jm/cache-entry-from-mem-pool'

For a large tree, the index needs to hold many cache entries
allocated on heap. These cache entries are now allocated out of a
dedicated memory pool to amortize malloc(3) overhead.

* jm/cache-entry-from-mem-pool:
block alloc: add validations around cache_entry lifecyle
block alloc: allocate cache entries from mem_pool
mem-pool: fill out functionality
mem-pool: add life cycle management functions
mem-pool: only search head block for available space
block alloc: add lifecycle APIs for cache_entry structs
read-cache: teach make_cache_entry to take object_id
read-cache: teach refresh_cache_entry to take istate

Merge branch 'jt/fetch-nego-tip'

"git fetch" learned a new option "--negotiation-tip" to limit the
set of commits it tells the other end as "have", to reduce wasted
bandwidth and cycles, which would be helpful when the receiving
repository has a lot of refs that have little to do with the
history at the remote it is fetching from.

* jt/fetch-nego-tip:
fetch-pack: support negotiation tip whitelist

Merge branch 'en/t6042-insane-merge-rename-testcases'

Various glitches in the heuristics of merge-recursive strategy have
been documented in new tests.

* en/t6042-insane-merge-rename-testcases:
t6042: add testcase covering long chains of rename conflicts
t6042: add testcase covering rename/rename(2to1)/delete/delete conflict
t6042: add testcase covering rename/add/delete conflict type

Merge branch 'sb/object-store-lookup'

lookup_commit_reference() and friends have been updated to find
in-core object for a specific in-core repository instance.

* sb/object-store-lookup: (32 commits)
commit.c: allow lookup_commit_reference to handle arbitrary repositories
commit.c: allow lookup_commit_reference_gently to handle arbitrary repositories
tag.c: allow deref_tag to handle arbitrary repositories
object.c: allow parse_object to handle arbitrary repositories
object.c: allow parse_object_buffer to handle arbitrary repositories
commit.c: allow get_cached_commit_buffer to handle arbitrary repositories
commit.c: allow set_commit_buffer to handle arbitrary repositories
commit.c: migrate the commit buffer to the parsed object store
commit-slabs: remove realloc counter outside of slab struct
commit.c: allow parse_commit_buffer to handle arbitrary repositories
tag: allow parse_tag_buffer to handle arbitrary repositories
tag: allow lookup_tag to handle arbitrary repositories
commit: allow lookup_commit to handle arbitrary repositories
tree: allow lookup_tree to handle arbitrary repositories
blob: allow lookup_blob to handle arbitrary repositories
object: allow lookup_object to handle arbitrary repositories
object: allow object_as_type to handle arbitrary repositories
tag: add repository argument to deref_tag
tag: add repository argument to parse_tag_buffer
tag: add repository argument to lookup_tag
...

Merge branch 'is/parsing-line-range'

Parsing of -L[<N>][,[<M>]] parameters "git blame" and "git log"
take has been tweaked.

* is/parsing-line-range:
log: prevent error if line range ends past end of file
blame: prevent error if range ends past end of file

Merge branch 'jt/fetch-pack-negotiator'

Code restructuring and a small fix to transport protocol v2 during
fetching.

* jt/fetch-pack-negotiator:
fetch-pack: introduce negotiator API
fetch-pack: move common check and marking together
fetch-pack: make negotiation-related vars local
fetch-pack: use ref adv. to prune "have" sent
fetch-pack: directly end negotiation if ACK ready
fetch-pack: clear marks before re-marking
fetch-pack: split up everything_local()

Merge branch 'ab/checkout-default-remote'

"git checkout" and "git worktree add" learned to honor
checkout.defaultRemote when auto-vivifying a local branch out of a
remote tracking branch in a repository with multiple remotes that
have tracking branches that share the same names.

* ab/checkout-default-remote:
checkout & worktree: introduce checkout.defaultRemote
checkout: add advice for ambiguous "checkout <branch>"
builtin/checkout.c: use "ret" variable for return
checkout: pass the "num_matches" up to callers
checkout.c: change "unique" member to "num_matches"
checkout.c: introduce an *_INIT macro
checkout.h: wrap the arguments to unique_tracking_name()
checkout tests: index should be clean after dwim checkout

Merge branch 'sb/diff-color-move-more'

"git diff --color-moved" feature has further been tweaked.

* sb/diff-color-move-more:
diff.c: offer config option to control ws handling in move detection
diff.c: add white space mode to move detection that allows indent changes
diff.c: factor advance_or_nullify out of mark_color_as_moved
diff.c: decouple white space treatment from move detection algorithm
diff.c: add a blocks mode for moved code detection
diff.c: adjust hash function signature to match hashmap expectation
diff.c: do not pass diff options as keydata to hashmap
t4015: avoid git as a pipe input
xdiff/xdiffi.c: remove unneeded function declarations
xdiff/xdiff.h: remove unused flags

Merge branch 'es/test-fixes'

Test clean-up and corrections.

* es/test-fixes: (26 commits)
t5608: fix broken &&-chain
t9119: fix broken &&-chains
t9000-t9999: fix broken &&-chains
t7000-t7999: fix broken &&-chains
t6000-t6999: fix broken &&-chains
t5000-t5999: fix broken &&-chains
t4000-t4999: fix broken &&-chains
t3030: fix broken &&-chains
t3000-t3999: fix broken &&-chains
t2000-t2999: fix broken &&-chains
t1000-t1999: fix broken &&-chains
t0000-t0999: fix broken &&-chains
t9814: simplify convoluted check that command correctly errors out
t9001: fix broken "invoke hook" test
t7810: use test_expect_code() instead of hand-rolled comparison
t7400: fix broken "submodule add/reconfigure --force" test
t7201: drop pointless "exit 0" at end of subshell
t6036: fix broken "merge fails but has appropriate contents" tests
t5505: modernize and simplify hard-to-digest test
t5406: use write_script() instead of birthing shell script manually
...

Merge branch 'ds/commit-graph-fsck'

"git fsck" learns to make sure the optional commit-graph file is in
a sane state.

* ds/commit-graph-fsck: (23 commits)
coccinelle: update commit.cocci
commit-graph: update design document
gc: automatically write commit-graph files
commit-graph: add '--reachable' option
commit-graph: use string-list API for input
fsck: verify commit-graph
commit-graph: verify contents match checksum
commit-graph: test for corrupted octopus edge
commit-graph: verify commit date
commit-graph: verify generation number
commit-graph: verify parent list
commit-graph: verify root tree OIDs
commit-graph: verify objects exist
commit-graph: verify corrupt OID fanout and lookup
commit-graph: verify required chunks are present
commit-graph: verify catches corrupt signature
commit-graph: add 'verify' subcommand
commit-graph: load a root tree from specific graph
commit: force commit to parse from object database
commit-graph: parse commit from chosen graph
...

Merge branch 'jk/fsck-gitmodules-gently'

Recent "security fix" to pay attention to contents of ".gitmodules"
while accepting "git push" was a bit overly strict than necessary,
which has been adjusted.

* jk/fsck-gitmodules-gently:
fsck: downgrade gitmodulesParse default to "info"
fsck: split ".gitmodules too large" error from parse failure
fsck: silence stderr when parsing .gitmodules
config: add options parameter to git_config_from_mem
config: add CONFIG_ERROR_SILENT handler
config: turn die_on_error into caller-facing enum

Merge branch 'bc/object-id'

Conversion from uchar[40] to struct object_id continues.

* bc/object-id:
pretty: switch hard-coded constants to the_hash_algo
sha1-file: convert constants to uses of the_hash_algo
log-tree: switch GIT_SHA1_HEXSZ to the_hash_algo->hexsz
diff: switch GIT_SHA1_HEXSZ to use the_hash_algo
builtin/merge-recursive: make hash independent
builtin/merge: switch to use the_hash_algo
builtin/fmt-merge-msg: make hash independent
builtin/update-index: simplify parsing of cacheinfo
builtin/update-index: convert to using the_hash_algo
refs/files-backend: use the_hash_algo for writing refs
sha1-name: use the_hash_algo when parsing object names
strbuf: allocate space with GIT_MAX_HEXSZ
commit: express tree entry constants in terms of the_hash_algo
hex: switch to using the_hash_algo
tree-walk: replace hard-coded constants with the_hash_algo
cache: update object ID functions for the_hash_algo

Merge branch 'en/t6036-recursive-corner-cases'

Tests to cover more D/F conflict cases have been added for
merge-recursive.

* en/t6036-recursive-corner-cases:
t6036: fix broken && chain in sub-shell
t6036: add lots of detail for directory/file conflicts in recursive case

Merge branch 'sg/httpd-test-unflake'

httpd tests saw occasional breakage due to the way its access log
gets inspected by the tests, which has been updated to make them
less flaky.

* sg/httpd-test-unflake:
t/lib-httpd: avoid occasional failures when checking access.log
t/lib-httpd: add the strip_access_log() helper function
t5541: clean up truncating access log

Merge branch 'bp/test-drop-caches-for-windows'

A test helper update for Windows.

* bp/test-drop-caches-for-windows:
handle lower case drive letters on Windows

Merge branch 'jk/has-uncommitted-changes-fix'

"git pull --rebase" on a corrupt HEAD caused a segfault. In
general we substitute an empty tree object when running the in-core
equivalent of the diff-index command, and the codepath has been
corrected to do so as well to fix this issue.

* jk/has-uncommitted-changes-fix:
has_uncommitted_changes(): fall back to empty tree

sha1dc: update from upstream

Update sha1dc from the latest version by the upstream
maintainer[1]. See 2db87328ef ("Merge branch 'ab/sha1dc'", 2017-07-10)
for the last update.

This fixes an issue where AIX was wrongly detected as a Little-endian
instead of a Big-endian system. See [2][3][4].

1. https://github.com/cr-marcstevens/sha1collisiondetection/commit/232357eb2ea0397388254a4b188333a227bf5b10
2. https://github.com/cr-marcstevens/sha1collisiondetection/pull/45
3. https://github.com/cr-marcstevens/sha1collisiondetection/pull/42
4. https://public-inbox.org/git/20180729200623.GF945730@genre.crustytoothpaste.net/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

score_trees(): fix iteration over trees with missing entries

In score_trees(), we walk over two sorted trees to find
which entries are missing or have different content between
the two. So if we have two trees with these entries:

one two
--- ---
a a
b c
c d

we'd expect the loop to:

- compare "a" to "a"

- compare "b" to "c"; because these are sorted lists, we
know that the second tree does not have "b"

- compare "c" to "c"

- compare "d" to end-of-list; we know that the first tree
does not have "d"

And prior to d8febde370 (match-trees: simplify score_trees()
using tree_entry(), 2013-03-24) that worked. But after that
commit, we mistakenly increment the tree pointers for every
loop iteration, even when we've processed the entry for only
one side. As a result, we end up doing this:

- compare "a" to "a"

- compare "b" to "c"; we know that we do not have "b", but
we still increment both tree pointers; at this point
we're out of sync and all further comparisons are wrong

- compare "c" to "d" and mistakenly claim that the second
tree does not have "c"

- exit the loop, mistakenly not realizing that the first
tree does not have "d"

So contrary to the claim in d8febde370, we really do need to
manually use update_tree_entry(), because advancing the tree
pointer depends on the entry comparison.

That means we must stop using tree_entry() to access each
entry, since it auto-advances the pointer. Instead:

- we'll use tree_desc.size directly to know if there's
anything left to look at (which is what tree_entry() was
doing under the hood)

- rather than do an extra struct assignment to "e1" and
"e2", we can just access the "entry" field of tree_desc
directly

That makes us a little more intimate with the tree_desc
code, but that's not uncommon for its callers.

The included test shows off the bug by adding a new entry
"bar.t", which sorts early in the tree and de-syncs the
comparison for "foo.t", which comes after.

Reported-by: George Shammas <georgyo@gmail.com>
Helped-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

remote: make refspec follow the same disambiguation rule as local refs

When matching a non-wildcard LHS of a refspec against a list of
refs, find_ref_by_name_abbrev() returns the first ref that matches
using any DWIM rules used by refname_match() in refs.c, even if a
better match occurs later in the list of refs.

This causes unexpected behavior when (for example) fetching using
the refspec "refs/heads/s:<something>" from a remote with both
"refs/heads/refs/heads/s" and "refs/heads/s"; even if the former was
inadvertently created, one would still expect the latter to be
fetched. Similarly, when both a tag T and a branch T exist,
fetching T should favor the tag, just like how local refname
disambiguation rule works. But because the code walks over
ls-remote output from the remote, which happens to be sorted in
alphabetical order and has refs/heads/T before refs/tags/T, a
request to fetch T is (mis)interpreted as fetching refs/heads/T.

Update refname_match(), all of whose current callers care only if it
returns non-zero (i.e. matches) to see if an abbreviated name can
mean the full name being tested, so that it returns a positive
integer whose magnitude can be used to tell the precedence, and fix
the find_ref_by_name_abbrev() function not to stop at the first
match but find the match with the highest precedence.

This is based on an earlier work, which special cased only the exact
matches, by Jonathan Tan.

Helped-by: Jonathan Tan <jonathantanmy@google.com>
Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fetch-pack: unify ref in and out param

When a user fetches:
- at least one up-to-date ref and at least one non-up-to-date ref,
- using HTTP with protocol v0 (or something else that uses the fetch
command of a remote helper)
some refs might not be updated after the fetch.

This bug was introduced in commit 989b8c4452 ("fetch-pack: put shallow
info in output parameter", 2018-06-28) which allowed transports to
report the refs that they have fetched in a new out-parameter
"fetched_refs". If they do so, transport_fetch_refs() makes this
information available to its caller.

Users of "fetched_refs" rely on the following 3 properties:
(1) it is the complete list of refs that was passed to
transport_fetch_refs(),
(2) it has shallow information (REF_STATUS_REJECT_SHALLOW set if
relevant), and
(3) it has updated OIDs if ref-in-want was used (introduced after
989b8c4452).

In an effort to satisfy (1), whenever transport_fetch_refs()
filters the refs sent to the transport, it re-adds the filtered refs to
whatever the transport supplies before returning it to the user.
However, the implementation in 989b8c4452 unconditionally re-adds the
filtered refs without checking if the transport refrained from reporting
anything in "fetched_refs" (which it is allowed to do), resulting in an
incomplete list, no longer satisfying (1).

An earlier effort to resolve this [1] solved the issue by readding the
filtered refs only if the transport did not refrain from reporting in
"fetched_refs", but after further discussion, it seems that the better
solution is to revert the API change that introduced "fetched_refs".
This API change was first suggested as part of a ref-in-want
implementation that allowed for ref patterns and, thus, there could be
drastic differences between the input refs and the refs actually fetched
[2]; we eventually decided to only allow exact ref names, but this API
change remained even though its necessity was decreased.

Therefore, revert this API change by reverting commit 989b8c4452, and
make receive_wanted_refs() update the OIDs in the sought array (like how
update_shallow() updates shallow information in the sought array)
instead. A test is also included to show that the user-visible bug
discussed at the beginning of this commit message no longer exists.

[1] https://public-inbox.org/git/20180801171806.GA122458@google.com/
[2] https://public-inbox.org/git/86a128c5fb710a41791e7183207c4d64889f9307.1485381677.git.jonathantanmy@google.com/

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-p4: add the `p4-pre-submit` hook

The `p4-pre-submit` hook is executed before git-p4 submits code.
If the hook exits with non-zero value, submit process not start.

Signed-off-by: Chen Bin <chenbin.sh@gmail.com>
Reviewed-by: Luke Diamand <luke@diamand.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

xdiff: reduce indent heuristic overhead

Skip searching for better indentation heuristics if we'd slide a hunk more
than its size. This is the easiest fix proposed in the analysis[1] in
response to a patch that mercurial took for xdiff to limit searching
by a constant. Using a performance test as:

#!python
open('a', 'w').write(" \n" * 1000000)
open('b', 'w').write(" \n" * 1000001)

This patch reduces the execution of "git diff --no-index a b" from
0.70s to 0.31s. However limiting the sliding to the size of the diff hunk,
which was proposed as a solution (that I found easiest to implement for
now) is not optimal for cases like

open('a', 'w').write(" \n" * 1000000)
open('b', 'w').write(" \n" * 2000000)

as then we'd still slide 1000000 times.

In addition to limiting the sliding to size of the hunk, also limit by a
constant. Choose 100 lines as the constant as that fits more than a screen,
which really means that the diff sliding is probably not providing a lot
of benefit anyway.

[1] https://public-inbox.org/git/72ac1ac2-f567-f241-41d6-d0f83072e0b3@alum.mit.edu/

Reported-by: Jun Wu <quark@fb.com>
Analysis-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t1300: document current behavior of setting options

This documents current behavior of the config machinery, when changing
the value of some settings. This patch just serves to provide a baseline
for the follow up that will fix some issues with the current behavior.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fetch doc: cross-link two new negotiation options

Users interested in the fetch.negotiationAlgorithm variable added in
42cc7485a2 ("negotiator/skipping: skip commits during fetch",
2018-07-16) are probably interested in the related --negotiation-tip
option added in 3390e42adb ("fetch-pack: support negotiation tip
whitelist", 2018-07-02).

Change the documentation for those two to reference one another to
point readers in the right direction.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

negotiator: unknown fetch.negotiationAlgorithm should error out

Change the handling of fetch.negotiationAlgorithm=<str> to error out
on unknown strings, i.e. everything except "default" or "skipping".

This changes the behavior added in 42cc7485a2 ("negotiator/skipping:
skip commits during fetch", 2018-07-16) which would ignore all unknown
values and silently fall back to the "default" value.

For a feature like this it's much better to produce an error than
proceed. We don't want users to debug some amazingly slow fetch that
should benefit from "skipping", only to find that they'd forgotten to
deploy the new git version on that particular machine.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Merge branch 'jt/fetch-nego-tip' into ab/fetch-nego

* jt/fetch-nego-tip:
fetch-pack: support negotiation tip whitelist

travis-ci: include the trash directories of failed tests in the trace log

The trash directory of a failed test might contain invaluable
information about the cause of the failure, but we have no access to
the trash directories of Travis CI build jobs. The only feedback we
get from there is the build job's trace log, so...

Modify 'ci/print-test-failures.sh' to create a tar.gz archive of the
trash directory of each failed test, encode that archive with base64,
and print the resulting block of ASCII text, so it gets embedded in
the trace log. Furthermore, run tests with '--immediate' to
faithfully preserve the failed state.

Extracting the trash directories from the trace log turned out to be a
bit of a hassle, partly because of the size of these logs (usually
resulting in several hundreds or even thousands of lines of
base64-encoded text), and partly because these logs have CRLF, CRCRLF
and occasionally even CRCRCRLF line endings, which cause 'base64 -d'
from coreutils to complain about "invalid input". For convenience add
a small script 'ci/util/extract-trash-dirs.sh', which will extract and
unpack all base64-encoded trash directories embedded in the log fed to
its standard input, and include an example command to be copy-pasted
into a terminal to do it all at the end of the failure report.

A few of our tests create sizeable trash directories, so limit the
size of each included base64-encoded block, let's say, to 1MB. And
just in case something fundamental gets broken and a lot of tests fail
at once, don't include trash directories when the combined size of the
included base64-encoded blocks would exceed 1MB.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

remote: clear string_list after use in mv()

Switch to the _DUP variant of string_list for remote_branches to allow
string_list_clear() to release the allocated memory at the end, and
actually call that function. Free the util pointer as well; it is
allocated in read_remote_branches().

NB: This string_list is empty until read_remote_branches() is called
via for_each_ref(), so there is no need to clean it up when returning
before that point.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

read-cache: fix directory/file conflict handling in read_index_unmerged()

read_index_unmerged() has two intended purposes:
* return 1 if there are any unmerged entries, 0 otherwise
* drops any higher-stage entries down to stage #0

There are several callers of read_index_unmerged() that check the return
value to see if it is non-zero, all of which then die() if that condition
is met. For these callers, dropping higher-stage entries down to stage #0
is a waste of resources, and returning immediately on first unmerged entry
would be better. But it's probably only a very minor difference and isn't
the focus of this series.

The remaining callers ignore the return value and call this function for
the side effect of dropping higher-stage entries down to stage #0. As
mentioned in commit e11d7b596970 ("'reset --merge': fix unmerged case",
2009-12-31),

The _only_ reason we want to keep a previously unmerged entry in the
index at stage #0 is so that we don't forget the fact that we have
corresponding file in the work tree in order to be able to remove it
when the tree we are resetting to does not have the path.

In fact, prior to commit d1a43f2aa4bf ("reset --hard/read-tree --reset -u:
remove unmerged new paths", 2008-10-15), read_index_unmerged() did just
remove unmerged entries from the cache immediately but that had the
unwanted effect of leaving around new untracked files in the tree from
aborted merges.

So, that's the intended purpose of this function. The problem is that
when directory/files conflicts are present, trying to add the file to the
index at stage 0 fails (because there is still a directory in the way),
and the function returns early with a -1 return code to signify the error.
As noted above, none of the callers who want the drop-to-stage-0 behavior
check the return status, though, so this means all remaining unmerged
entries remain in the index and the callers proceed assuming otherwise.
Users then see errors of the form:

error: 'DIR-OR-FILE' appears as both a file and as a directory
error: DIR-OR-FILE: cannot drop to stage #0

and potentially also messages about other unmerged entries which came
lexicographically later than whatever pathname was both a file and a
directory. Google finds a few hits searching for those messages,
suggesting there were probably a couple people who hit this besides me.
Luckily, calling `git reset --hard` multiple times would workaround
this bug.

Since the whole purpose here is to just put the entry *temporarily* into
the index so that any associated file in the working copy can be removed,
we can just skip the DFCHECK and allow both the file and directory to
appear in the index. The temporary simultaneous appearance of the
directory and file entries in the index will be removed by the callers
by calling unpack_trees(), which excludes these unmerged entries marked
with CE_CONFLICTED flag from the resulting index, before they attempt to
write the index anywhere.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t1015: demonstrate directory/file conflict recovery failures

Several "recovery" commands outright fail or do not fully recover
when directory-file conflicts are present. This includes:
* git read-tree --reset HEAD
* git am --skip
* git am --abort
* git merge --abort
* git reset --hard

Add testcases documenting these shortcomings.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sequencer: don't die() on bogus user-edited timestamp

read_author_ident() is careful to handle errors "gently" when parsing
"rebase-merge/author-script" by printing a suitable warning and
returning NULL; it never die()'s. One possible reason that parsing might
fail is that "rebase-merge/author-script" has been hand-edited in such a
way which corrupts it or the information it contains.

However, read_author_ident() invokes fmt_ident() which is not so careful
about failing "gently". It will die() if it encounters a malformed
timestamp. Since read_author_ident() doesn't want to die() and since
it's dealing with possibly hand-edited data, take care to avoid passing
a bogus timestamp to fmt_ident().

A more "correctly engineered" fix would be to add a "gentle" version of
fmt_ident(), however, such a change it outside the scope of the bug-fix
series. If fmt_ident() ever does grow a "gentle" cousin, then the manual
timestamp check added here can be retired.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>