Merge branch 'js/mingw-http-ssl'

On platforms with recent cURL library, http.sslBackend configuration
variable can be used to choose a different SSL backend at runtime.
The Windows port uses this mechanism to switch between OpenSSL and
Secure Channel while talking over the HTTPS protocol.

* js/mingw-http-ssl:
http: when using Secure Channel, ignore sslCAInfo by default
http: add support for disabling SSL revocation checks in cURL
http: add support for selecting SSL backends at runtime

Merge branch 'mg/gpg-fingerprint'

New "--pretty=format:" placeholders %GF and %GP that show the GPG
key fingerprints have been invented.

* mg/gpg-fingerprint:
gpg-interface.c: obtain primary key fingerprint as well
gpg-interface.c: support getting key fingerprint via %GF format
gpg-interface.c: use flags to determine key/signer info presence

Merge branch 'mg/gpg-parse-tighten'

Detect and reject a signature block that has more than one GPG
signature.

* mg/gpg-parse-tighten:
gpg-interface.c: detect and reject multiple signatures on commits

Merge branch 'en/merge-cleanup-more'

Further clean-up of merge-recursive machinery.

* en/merge-cleanup-more:
merge-recursive: avoid showing conflicts with merge branch before HEAD
merge-recursive: improve auto-merging messages with path collisions

add: speed up cmd_add() by utilizing read_cache_preload()

During an "add", a call is made to run_diff_files() which calls
check_removed() for each index-entry. The preload_index() code
distributes some of the costs across multiple threads.

Because the files checked are restricted to pathspec, adding
individual files makes no measurable impact but on a Windows repo
with ~200K files, 'git add .' drops from 6.3 seconds to 3.3 seconds
for a 47% savings.

Signed-off-by: Ben Peart <benpeart@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

remote: make add_missing_tags() linear

The add_missing_tags() method currently has quadratic behavior.
This is due to a linear number (based on number of tags T) of
calls to in_merge_bases_many, which has linear performance (based
on number of commits C in the repository).

Replace this O(T * C) algorithm with an O(T + C) algorithm by
using get_reachable_subset(). We ignore the return list and focus
instead on the reachable_flag assigned to the commits we care
about, because we need to interact with the tag ref and not just
the commit object.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

test-reach: test get_reachable_subset

The get_reachable_subset() method returns the list of commits in
the 'to' array that are reachable from at least one commit in the
'from' array. Add tests that check this method works in a few
cases:

1. All commits in the 'to' list are reachable. This exercises the
early-termination condition.

2. Some commits in the 'to' list are reachable. This exercises the
loop-termination condition.

3. No commits in the 'to' list are reachable. This exercises the
NULL return condition.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

commit-reach: implement get_reachable_subset

The existing reachability algorithms in commit-reach.c focus on
finding merge-bases or determining if all commits in a set X can
reach at least one commit in a set Y. However, for two commits sets
X and Y, we may also care about which commits in Y are reachable
from at least one commit in X.

Implement get_reachable_subset() which answers this question. Given
two arrays of commits, 'from' and 'to', return a commit_list with
every commit from the 'to' array that is reachable from at least
one commit in the 'from' array.

The algorithm is a simple walk starting at the 'from' commits, using
the PARENT2 flag to indicate "this commit has already been added to
the walk queue". By marking the 'to' commits with the PARENT1 flag,
we can determine when we see a commit from the 'to' array. We remove
the PARENT1 flag as we add that commit to the result list to avoid
duplicates.

The order of the resulting list is a reverse of the order that the
commits are discovered in the walk.

There are a couple shortcuts to avoid walking more than we need:

1. We determine the minimum generation number of commits in the
'to' array. We do not walk commits with generation number
below this minimum.

2. We count how many distinct commits are in the 'to' array, and
decrement this count when we discover a 'to' commit during the
walk. If this number reaches zero, then we can terminate the
walk.

Tests will be added using the 'test-tool reach' helper in a
subsequent commit.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

send-email: avoid empty transfer encoding header

Fix a small bug introduced by "7a36987ff (send-email: add an auto option
for transfer encoding, 2018-07-14)".

I saw the following message when setting --transfer-encoding for a file
with the same encoding:

$ git send-email --transfer-encoding=8bit example.patch
Use of uninitialized value $xfer_encoding in concatenation (.) or string
at /usr/lib/git-core/git-send-email line 1744.

The new tests are by brian m. carlson.

Signed-off-by: Aaron Lindsay <aaron@aclindsay.com>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

pathspec: handle non-terminated strings with :(attr)

The pathspec code always takes names to be matched as a
name/namelen pair, but match_attrs() never looks at namelen,
and just treats "name" like a NUL-terminated string, passing
it to git_check_attr().

This usually works anyway. Every caller passes a
NUL-terminated string, and in all but one the passed-in
length is the same as the length of the string (the
exception is dir_path_match(), which may pass a smaller
length to drop a trailing slash). So we won't currently ever
read random memory, and the one case I found actually
happens to work correctly because the attr code can handle
the trailing slash itself.

But it's still worth addressing, as the function interface
implies that the name does not have to be NUL-terminated,
making this an accident waiting to happen.

Since teaching git_check_attr() to take a ptr/len pair would
be a big refactor, we'll just allocate a new string. We can
do this only when necessary, which avoids paying the cost
for most callers.

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

approxidate: handle pending number for "specials"

The approxidate parser has a table of special keywords like
"yesterday", "noon", "pm", etc. Some of these, like "pm", do
the right thing if we've recently seen a number: "3pm" is
what you'd think.

However, most of them do not look at or modify the
pending-number flag at all, which means a number may "jump"
across a significant keyword and be used unexpectedly. For
example, when parsing:

January 5th noon pm

we'd connect the "5" to "pm", and ignore it as a
day-of-month. This is obviously a bit silly, as "noon"
already implies "pm". And other mis-parsed things are
generally as silly ("January 5th noon, years ago" would
connect the 5 to "years", but probably nobody would type
that).

However, the fix is simple: when we see a keyword like
"noon", we should flush the pending number (as we would if
we hit another number, or the end of the string). In a few
of the specials that actually modify the day, we can simply
throw away the number (saying "Jan 5 yesterday" should not
respect the number at all).

Note that we have to either move or forward-declare the
static pending_number() to make it accessible to these
functions; this patch moves it.

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

rev-list: handle flags for --indexed-objects

When a traversal sees the --indexed-objects option, it adds
all blobs and valid cache-trees from the index to the
traversal using add_index_objects_to_pending(). But that
function totally ignores its flags parameter!

That means that doing:

git rev-list --objects --indexed-objects

and

git rev-list --objects --not --indexed-objects

produce the same output, because we ignore the UNINTERESTING
flag when walking the index in the second example.

Nobody noticed because this feature was added as a way for
tools like repack to increase their coverage of reachable
objects, meaning it would only be used like the first
example above.

But since it's user facing (and because the documentation
describes it "as if the objects are listed on the command
line"), we should make sure the negative case behaves
sensibly.

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

xdiff-interface: provide a separate consume callback for hunks

The previous commit taught xdiff to optionally provide the hunk header
data to a specialized callback. But most users of xdiff actually use our
more convenient xdi_diff_outf() helper, which ensures that our callbacks
are always fed whole lines.

Let's plumb the special hunk-callback through this interface, too. It
will follow the same rule as xdiff when the hunk callback is NULL (i.e.,
continue to pass a stringified hunk header to the line callback). Since
we add NULL to each caller, there should be no behavior change yet.

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

xdiff: provide a separate emit callback for hunks

The xdiff library always emits hunk header lines to our callbacks as
formatted strings like "@@ -a,b +c,d @@\n". This is convenient if we're
going to output a diff, but less so if we actually need to compute using
those numbers, which requires re-parsing the line.

In preparation for moving away from this, let's teach xdiff a new
callback function which gets the broken-out hunk information. To help
callers that don't want to use this new callback, if it's NULL we'll
continue to format the hunk header into a string.

Note that this function renames the "outf" callback to "out_line", as
well. This isn't strictly necessary, but helps in two ways:

1. Now that there are two callbacks, it's nice to use more descriptive
names.

2. Many callers did not zero the emit_callback_data struct, and needed
to be modified to set ecb.out_hunk to NULL. By changing the name of
the existing struct member, that guarantees that any new callers
from in-flight topics will break the build and be examined
manually.

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

t6012: make rev-list tests more interesting

As we are working to rewrite some of the revision-walk machinery,
there could easily be some interesting interactions between the
options that force topological constraints (--topo-order,
--date-order, and --author-date-order) along with specifying a
path.

Add extra tests to t6012-rev-list-simplify.sh to add coverage of
these interactions. To ensure interesting things occur, alter the
repo data shape to have different orders depending on topo-, date-,
or author-date-order.

When testing using GIT_TEST_COMMIT_GRAPH, this assists in covering
the new logic for topo-order walks using generation numbers. The
extra tests can be added indepently.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

revision.c: generation-based topo-order algorithm

The current --topo-order algorithm requires walking all
reachable commits up front, topo-sorting them, all before
outputting the first value. This patch introduces a new
algorithm which uses stored generation numbers to
incrementally walk in topo-order, outputting commits as
we go. This can dramatically reduce the computation time
to write a fixed number of commits, such as when limiting
with "-n <N>" or filling the first page of a pager.

When running a command like 'git rev-list --topo-order HEAD',
Git performed the following steps:

1. Run limit_list(), which parses all reachable commits,
adds them to a linked list, and distributes UNINTERESTING
flags. If all unprocessed commits are UNINTERESTING, then
it may terminate without walking all reachable commits.
This does not occur if we do not specify UNINTERESTING
commits.

2. Run sort_in_topological_order(), which is an implementation
of Kahn's algorithm. It first iterates through the entire
set of important commits and computes the in-degree of each
(plus one, as we use 'zero' as a special value here). Then,
we walk the commits in priority order, adding them to the
priority queue if and only if their in-degree is one. As
we remove commits from this priority queue, we decrement the
in-degree of their parents.

3. While we are peeling commits for output, get_revision_1()
uses pop_commit on the full list of commits computed by
sort_in_topological_order().

In the new algorithm, these three steps correspond to three
different commit walks. We run these walks simultaneously,
and advance each only as far as necessary to satisfy the
requirements of the 'higher order' walk. We know when we can
pause each walk by using generation numbers from the commit-
graph feature.

Recall that the generation number of a commit satisfies:

* If the commit has at least one parent, then the generation
number is one more than the maximum generation number among
its parents.

* If the commit has no parent, then the generation number is one.

There are two special generation numbers:

* GENERATION_NUMBER_INFINITY: this value is 0xffffffff and
indicates that the commit is not stored in the commit-graph and
the generation number was not previously calculated.

* GENERATION_NUMBER_ZERO: this value (0) is a special indicator
to say that the commit-graph was generated by a version of Git
that does not compute generation numbers (such as v2.18.0).

Since we use generation_numbers_enabled() before using the new
algorithm, we do not need to worry about GENERATION_NUMBER_ZERO.
However, the existence of GENERATION_NUMBER_INFINITY implies the
following weaker statement than the usual we expect from
generation numbers:

If A and B are commits with generation numbers gen(A) and
gen(B) and gen(A) < gen(B), then A cannot reach B.

Thus, we will walk in each of our stages until the "maximum
unexpanded generation number" is strictly lower than the
generation number of a commit we are about to use.

The walks are as follows:

1. EXPLORE: using the explore_queue priority queue (ordered by
maximizing the generation number), parse each reachable
commit until all commits in the queue have generation
number strictly lower than needed. During this walk, update
the UNINTERESTING flags as necessary.

2. INDEGREE: using the indegree_queue priority queue (ordered
by maximizing the generation number), add one to the in-
degree of each parent for each commit that is walked. Since
we walk in order of decreasing generation number, we know
that discovering an in-degree value of 0 means the value for
that commit was not initialized, so should be initialized to
two. (Recall that in-degree value "1" is what we use to say a
commit is ready for output.) As we iterate the parents of a
commit during this walk, ensure the EXPLORE walk has walked
beyond their generation numbers.

3. TOPO: using the topo_queue priority queue (ordered based on
the sort_order given, which could be commit-date, author-
date, or typical topo-order which treats the queue as a LIFO
stack), remove a commit from the queue and decrement the
in-degree of each parent. If a parent has an in-degree of
one, then we add it to the topo_queue. Before we decrement
the in-degree, however, ensure the INDEGREE walk has walked
beyond that generation number.

The implementations of these walks are in the following methods:

* explore_walk_step and explore_to_depth
* indegree_walk_step and compute_indegrees_to_depth
* next_topo_commit and expand_topo_walk

These methods have some patterns that may seem strange at first,
but they are probably carry-overs from their equivalents in
limit_list and sort_in_topological_order.

One thing that is missing from this implementation is a proper
way to stop walking when the entire queue is UNINTERESTING, so
this implementation is not enabled by comparisions, such as in
'git rev-list --topo-order A..B'. This can be updated in the
future.

In my local testing, I used the following Git commands on the
Linux repository in three modes: HEAD~1 with no commit-graph,
HEAD~1 with a commit-graph, and HEAD with a commit-graph. This
allows comparing the benefits we get from parsing commits from
the commit-graph and then again the benefits we get by
restricting the set of commits we walk.

Test: git rev-list --topo-order -100 HEAD
HEAD~1, no commit-graph: 6.80 s
HEAD~1, w/ commit-graph: 0.77 s
HEAD, w/ commit-graph: 0.02 s

Test: git rev-list --topo-order -100 HEAD -- tools
HEAD~1, no commit-graph: 9.63 s
HEAD~1, w/ commit-graph: 6.06 s
HEAD, w/ commit-graph: 0.06 s

This speedup is due to a few things. First, the new generation-
number-enabled algorithm walks commits on order of the number of
results output (subject to some branching structure expectations).
Since we limit to 100 results, we are running a query similar to
filling a single page of results. Second, when specifying a path,
we must parse the root tree object for each commit we walk. The
previous benefits from the commit-graph are entirely from reading
the commit-graph instead of parsing commits. Since we need to
parse trees for the same number of commits as before, we slow
down significantly from the non-path-based query.

For the test above, I specifically selected a path that is changed
frequently, including by merge commits. A less-frequently-changed
path (such as 'README') has similar end-to-end time since we need
to walk the same number of commits (before determining we do not
have 100 hits). However, get the benefit that the output is
presented to the user as it is discovered, much the same as a
normal 'git log' command (no '--topo-order'). This is an improved
user experience, even if the command has the same runtime.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

commit/revisions: bookkeeping before refactoring

There are a few things that need to move around a little before
making a big refactoring in the topo-order logic:

1. We need access to record_author_date() and
compare_commits_by_author_date() in revision.c. These are used
currently by sort_in_topological_order() in commit.c.

2. Moving these methods to commit.h requires adding an author_date_slab
declaration to commit.h. Consumers will need their own implementation.

3. The add_parents_to_list() method in revision.c performs logic
around the UNINTERESTING flag and other special cases depending
on the struct rev_info. Allow this method to ignore a NULL 'list'
parameter, as we will not be populating the list for our walk.
Also rename the method to the slightly more generic name
process_parents() to make clear that this method does more than
add to a list (and no list is required anymore).

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

revision.c: begin refactoring --topo-order logic

When running 'git rev-list --topo-order' and its kin, the topo_order
setting in struct rev_info implies the limited setting. This means
that the following things happen during prepare_revision_walk():

* revs->limited implies we run limit_list() to walk the entire
reachable set. There are some short-cuts here, such as if we
perform a range query like 'git rev-list COMPARE..HEAD' and we
can stop limit_list() when all queued commits are uninteresting.

* revs->topo_order implies we run sort_in_topological_order(). See
the implementation of that method in commit.c. It implies that
the full set of commits to order is in the given commit_list.

These two methods imply that a 'git rev-list --topo-order HEAD'
command must walk the entire reachable set of commits _twice_ before
returning a single result.

If we have a commit-graph file with generation numbers computed, then
there is a better way. This patch introduces some necessary logic
redirection when we are in this situation.

In v2.18.0, the commit-graph file contains zero-valued bytes in the
positions where the generation number is stored in v2.19.0 and later.
Thus, we use generation_numbers_enabled() to check if the commit-graph
is available and has non-zero generation numbers.

When setting revs->limited only because revs->topo_order is true,
only do so if generation numbers are not available. There is no
reason to use the new logic as it will behave similarly when all
generation numbers are INFINITY or ZERO.

In prepare_revision_walk(), if we have revs->topo_order but not
revs->limited, then we trigger the new logic. It breaks the logic
into three pieces, to fit with the existing framework:

1. init_topo_walk() fills a new struct topo_walk_info in the rev_info
struct. We use the presence of this struct as a signal to use the
new methods during our walk. In this patch, this method simply
calls limit_list() and sort_in_topological_order(). In the future,
this method will set up a new data structure to perform that logic
in-line.

2. next_topo_commit() provides get_revision_1() with the next topo-
ordered commit in the list. Currently, this simply pops the commit
from revs->commits.

3. expand_topo_walk() provides get_revision_1() with a way to signal
walking beyond the latest commit. Currently, this calls
add_parents_to_list() exactly like the old logic.

While this commit presents method redirection for performing the
exact same logic as before, it allows the next commit to focus only
on the new logic.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

test-reach: add rev-list tests

The rev-list command is critical to Git's functionality. Ensure it
works in the three commit-graph environments constructed in
t6600-test-reach.sh. Here are a few important types of rev-list
operations:

* Basic: git rev-list --topo-order HEAD
* Range: git rev-list --topo-order compare..HEAD
* Ancestry: git rev-list --topo-order --ancestry-path compare..HEAD
* Symmetric Difference: git rev-list --topo-order compare...HEAD

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

test-reach: add run_three_modes method

The 'test_three_modes' method assumes we are using the 'test-tool
reach' command for our test. However, we may want to use the data
shape of our commit graph and the three modes (no commit-graph,
full commit-graph, partial commit-graph) for other git commands.

Split test_three_modes to be a simple translation on a more general
run_three_modes method that executes the given command and tests
the actual output to the expected output.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

prio-queue: add 'peek' operation

When consuming a priority queue, it can be convenient to inspect
the next object that will be dequeued without actually dequeueing
it. Our existing library did not have such a 'peek' operation, so
add it as prio_queue_peek().

Add a reference-level comparison in t/helper/test-prio-queue.c
so this method is exercised by t0009-prio-queue.sh. Further, add
a test that checks the behavior when the compare function is NULL
(i.e. the queue becomes a stack).

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

travis-ci: install packages in 'ci/install-dependencies.sh'

Ever since we started using Travis CI, we specified the list of
packages to install in '.travis.yml' via the APT addon. While running
our builds on Travis CI's container-based infrastructure we didn't
have another choice, because that environment didn't support 'sudo',
and thus we didn't have permission to install packages ourselves. With
the switch to the VM-based infrastructure in the previous patch we do
get a working 'sudo', so we can install packages by running 'sudo
apt-get -y install ...' as well.

Let's make use of this and install necessary packages in
'ci/install-dependencies.sh', so all the dependencies (i.e. both
packages and "non-packages" (P4 and Git-LFS)) are handled in the same
file. Install gcc-8 only in the 'linux-gcc' build job; so far it has
been unnecessarily installed in the 'linux-clang' build job as well.
Print the versions of P4 and Git-LFS conditionally, i.e. only when
they have been installed; with this change even the static analysis
and documentation build jobs start using 'ci/install-dependencies.sh'
to install packages, and neither of these two build jobs depend on and
thus install those.

This change will presumably be beneficial for the upcoming Azure
Pipelines integration [1]: preliminary versions of that patch series
run a couple of 'apt-get' commands to install the necessary packages
before running 'ci/install-dependencies.sh', but with this patch it
will be sufficient to run only 'ci/install-dependencies.sh'.

[1] https://public-inbox.org/git/1a22efe849d6da79f2c639c62a1483361a130238.1539598316.git.gitgitgadget@gmail.com/

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

tests: optionally skip `git rebase -p` tests

The `--preserve-merges` mode of the `rebase` command is slated to be
deprecated soon, as the more powerful `--rebase-merges` mode is
available now, and the latter was designed with the express intent to
address the shortcomings of `--preserve-merges`' design (e.g. the
inability to reorder commits in an interactive rebase).

As such, we will eventually even remove the `--preserve-merges` support,
and along with it, its tests.

In preparation for this, and also to allow the Windows phase of our
automated tests to save some well-needed time when running the test
suite, this commit introduces a new prerequisite REBASE_P, which can be
forced to being unmet by setting the environment variable
`GIT_TEST_SKIP_REBASE_P` to any non-empty string.

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

t3418: decouple test cases from a previous `rebase -p` test case

It is in general a good idea for regression test cases to be as
independent of each other as possible (with the one exception of an
initial `setup` test case, which is only a test case in Git's test suite
because it does not have a notion of a fixture or setup).

This patch addresses one particular instance of this principle being
violated: a few test cases in t3418-rebase-continue.sh depend on a side
effect of a test case that verifies a specific `rebase -p` behavior. The
later test cases should, however, still succeed even if the `rebase -p`
test case is skipped.

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

t3404: decouple some test cases from outcomes of previous test cases

Originally, the `--preserve-merges` option of the `git rebase` command
piggy-backed on top of the `--interactive` feature. For that reason, the
early test cases were added to the very same test script that contains
the `git rebase -i` tests: `t3404-rebase-interactive.sh`.

However, since c42abfe7857 (rebase: introduce a dedicated backend for
--preserve-merges, 2018-05-28), the `--preserve-merges` feature got its
own backend, in preparation for converting the rest of the
`--interactive` code to built-in code, written in C rather than shell.

The reason why the `--preserve-merges` feature was not converted at the
same time is that we have something much better now: `--rebase-merges`.
That option intends to supersede `--preserve-merges`, and we will
probably deprecate the latter soon.

Once `--preserve-merges` has been deprecated for a good amount of time,
it will be time to remove it, and along with it, its tests.

In preparation for that, let's make the rest of the test cases in
`t3404-rebase-interactive.sh` independent of the test cases dedicated to
`--preserve-merges`.

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

Eighth batch for 2.20

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

rebase: apply cocci patch

Favor oideq() over !oidcmp() when checking for equality.

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

Merge branch 'js/rebase-i-shortopt'

"git rebase -i" learned to take 'b' as the short form of 'break'
option in the todo list.

* js/rebase-i-shortopt:
rebase -i: recognize short commands without arguments

Merge branch 'js/rebase-i-break'

"git rebase -i" learned a new insn, 'break', that the user can
insert in the to-do list. Upon hitting it, the command returns
control back to the user.

* js/rebase-i-break:
rebase -i: introduce the 'break' command
rebase -i: clarify what happens on a failed `exec`

Merge branch 'js/rebase-autostash-fix'

"git rebase" that has recently been rewritten in C had a few issues
in its "--autstash" feature, which have been corrected.

* js/rebase-autostash-fix:
rebase --autostash: fix issue with dirty submodules
rebase --autostash: demonstrate a problem with dirty submodules
rebase (autostash): use an explicit OID to apply the stash
rebase (autostash): store the full OID in <state-dir>/autostash
rebase (autostash): avoid duplicate call to state_dir_path()

Merge branch 'cb/printf-empty-format'

Build fix for a topic in flight.

* cb/printf-empty-format:
sequencer: cleanup for gcc warning in non developer mode

Merge branch 'jc/rebase-in-c-5-test-typofix'

Typofix.

* jc/rebase-in-c-5-test-typofix:
rebase: fix typoes in error messages

Merge branch 'pk/rebase-in-c-6-final'

The final step of rewriting "rebase -i" in C.

* pk/rebase-in-c-6-final:
rebase: default to using the builtin rebase

Merge branch 'js/rebase-in-c-5.5-work-with-rebase-i-in-c'

"rebase" that has been rewritten learns the new calling convention
used by "rebase -i" that was rewritten in C, tying the loose end
between two GSoC topics that stomped on each other's toes.

* js/rebase-in-c-5.5-work-with-rebase-i-in-c:
builtin rebase: prepare for builtin rebase -i

Merge branch 'pk/rebase-in-c-5-test'

Rewrite "git rebase" in C.

* pk/rebase-in-c-5-test:
builtin rebase: error out on incompatible option/mode combinations
builtin rebase: use no-op editor when interactive is "implied"
builtin rebase: show progress when connected to a terminal
builtin rebase: fast-forward to onto if it is a proper descendant
builtin rebase: optionally pass custom reflogs to reset_head()
builtin rebase: optionally auto-detect the upstream

Merge branch 'pk/rebase-in-c-4-opts'

Rewrite "git rebase" in C.

* pk/rebase-in-c-4-opts:
builtin rebase: support --root
builtin rebase: add support for custom merge strategies
builtin rebase: support `fork-point` option
merge-base --fork-point: extract libified function
builtin rebase: support --rebase-merges[=[no-]rebase-cousins]
builtin rebase: support `--allow-empty-message` option
builtin rebase: support `--exec`
builtin rebase: support `--autostash` option
builtin rebase: support `-C` and `--whitespace=<type>`
builtin rebase: support `--gpg-sign` option
builtin rebase: support `--autosquash`
builtin rebase: support `keep-empty` option
builtin rebase: support `ignore-date` option
builtin rebase: support `ignore-whitespace` option
builtin rebase: support --committer-date-is-author-date
builtin rebase: support --rerere-autoupdate
builtin rebase: support --signoff
builtin rebase: allow selecting the rebase "backend"

Merge branch 'pk/rebase-in-c-3-acts'

Rewrite "git rebase" in C.

* pk/rebase-in-c-3-acts:
builtin rebase: stop if `git am` is in progress
builtin rebase: actions require a rebase in progress
builtin rebase: support --edit-todo and --show-current-patch
builtin rebase: support --quit
builtin rebase: support --abort
builtin rebase: support --skip
builtin rebase: support --continue

Merge branch 'pk/rebase-in-c-2-basic'

Rewrite "git rebase" in C.

* pk/rebase-in-c-2-basic:
builtin rebase: support `git rebase <upstream> <switch-to>`
builtin rebase: only store fully-qualified refs in `options.head_name`
builtin rebase: start a new rebase only if none is in progress
builtin rebase: support --force-rebase
builtin rebase: try to fast forward when possible
builtin rebase: require a clean worktree
builtin rebase: support the `verbose` and `diffstat` options
builtin rebase: support --quiet
builtin rebase: handle the pre-rebase hook and --no-verify
builtin rebase: support `git rebase --onto A...B`
builtin rebase: support --onto

Merge branch 'ag/rebase-i-in-c'

Rewrite of the remaining "rebase -i" machinery in C.

* ag/rebase-i-in-c:
rebase -i: move rebase--helper modes to rebase--interactive
rebase -i: remove git-rebase--interactive.sh
rebase--interactive2: rewrite the submodes of interactive rebase in C
rebase -i: implement the main part of interactive rebase as a builtin
rebase -i: rewrite init_basic_state() in C
rebase -i: rewrite write_basic_state() in C
rebase -i: rewrite the rest of init_revisions_and_shortrevisions() in C
rebase -i: implement the logic to initialize $revisions in C
rebase -i: remove unused modes and functions
rebase -i: rewrite complete_action() in C
t3404: todo list with commented-out commands only aborts
sequencer: change the way skip_unnecessary_picks() returns its result
sequencer: refactor append_todo_help() to write its message to a buffer
rebase -i: rewrite checkout_onto() in C
rebase -i: rewrite setup_reflog_action() in C
sequencer: add a new function to silence a command, except if it fails
rebase -i: rewrite the edit-todo functionality in C
editor: add a function to launch the sequence editor
rebase -i: rewrite append_todo_help() in C
sequencer: make three functions and an enum from sequencer.c public

Merge branch 'pk/rebase-in-c'

Rewrite of the "rebase" machinery in C.

* pk/rebase-in-c:
builtin/rebase: support running "git rebase <upstream>"
rebase: refactor common shell functions into their own file
rebase: start implementing it as a builtin

fetch: replace string-list used as a look-up table with a hashmap

In find_non_local_tags() helper function (used to implement the
"follow tags"), we use string_list_has_string() on two string lists
as a way to see if a refname has already been processed, etc.

All this code predates more modern in-core lookup API like hashmap;
replace them with two hashmaps and one string list---the hashmaps
are used for look-ups and the string list is to keep the order of
items in the returned result stable (which is the only single thing
hashmap does worse than lookups on string-list).

Similarly, get_ref_map() uses another string-list as a look-up table
for existing refs. Replace it with a hashmap.

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

rev-parse: clear --exclude list after 'git rev-parse --all'

Commit [1] added the --exclude option to revision.c. The --all,
--branches, --tags, --remotes, and --glob options clear the exclude
list. Shortly therafter, commit [2] added the same to 'git rev-parse',
but without clearing the exclude list for the --all option.

[1] e7b432c52 ("revision: introduce --exclude=<glob> to tame wildcards", 2013-08-30)
[2] 9dc01bf06 ("rev-parse: introduce --exclude=<glob> to tame wildcards", 2013-11-01)

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

fetch-pack: be more precise in parsing v2 response

Each section in a protocol v2 response is followed by either a DELIM
packet (indicating more sections to follow) or a FLUSH packet
(indicating none to follow). But when parsing the "acknowledgments"
section, do_fetch_pack_v2() is liberal in accepting both, but determines
whether to continue reading or not based solely on the contents of the
"acknowledgments" section, not on whether DELIM or FLUSH was read.

There is no issue with a protocol-compliant server, but can result in
confusing error messages when communicating with a server that
serves unexpected additional sections. Consider a server that sends
"new-section" after "acknowledgments":

- client writes request
- client reads the "acknowledgments" section which contains no "ready",
then DELIM
- since there was no "ready", client needs to continue negotiation, and
writes request
- client reads "new-section", and reports to the end user "expected
'acknowledgments', received 'new-section'"

For the person debugging the involved Git implementation(s), the error
message is confusing in that "new-section" was not received in response
to the latest request, but to the first one.

One solution is to always continue reading after DELIM, but in this
case, we can do better. We know from the protocol that "ready" means at
least the packfile section is coming (hence, DELIM) and that no "ready"
means that no sections are to follow (hence, FLUSH). So teach
process_acks() to enforce this.

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

sequencer: use read_author_script()

Use the new function added in the last commit to read the author
script, updating read_env_script() and read_author_ident(). We now
have a single code path that reads the author script for am and all
flavors of rebase. This changes the behavior of read_env_script() as
previously it would set any environment variables that were in the
author-script file. Now it is an error if the file contains other
variables or any of GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL and
GIT_AUTHOR_DATE are missing. This is what am and the non interactive
version of rebase have been doing for several years so hopefully it
will not cause a problem for interactive rebase users. The advantage
is that we are reusing existing code from am which uses sq_dequote()
to properly dequote variables. This fixes potential problems with user
edited scripts as read_env_script() which did not track quotes
properly.

This commit also removes the fallback code for checking for a broken
author script after git is upgraded when a rebase is stopped. Now that
the parsing uses sq_dequote() it will reliably return an error if the
quoting is broken and the user will have to abort the rebase and
restart. This isn't ideal but it's a corner case and the detection of
the broken quoting could be confused by user edited author scripts.

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

add read_author_script() to libgit

Add read_author_script() to sequencer.c based on the implementation in
builtin/am.c and update read_am_author_script() to use
read_author_script(). The sequencer code that reads the author script
will be updated in the next commit.

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

am: rename read_author_script()

Rename read_author_script() in preparation for adding a shared
read_author_script() function to libgit.

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

am: improve author-script error reporting

If there are errors in a user edited author-script there was no
indication of what was wrong. This commit adds some specific error messages
depending on the problem. It also relaxes the requirement that the
variables appear in a specific order in the file to match the behavior
of 'rebase --interactive'.

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

am: don't die in read_author_script()

The caller is already prepared to handle errors returned from this
function so there is no need for it to die if it cannot read the file.

Suggested-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>

t/helper: add test-submodule-nested-repo-config

Add a test tool to exercise config_from_gitmodules(), in particular for
the case of nested submodules.

Add also a test to document that reading the submoudles config of nested
submodules does not work yet when the .gitmodules file is not in the
working tree but it still in the index.

This is because the git API does not always make it possible access the
object store of an arbitrary repository (see get_oid() usage in
config_from_gitmodules()).

When this git limitation gets fixed the aforementioned use case will be
supported too.

Signed-off-by: Antonio Ospite <ao2@ao2.it>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

submodule: support reading .gitmodules when it's not in the working tree

When the .gitmodules file is not available in the working tree, try
using the content from the index and from the current branch. This
covers the case when the file is part of the repository but for some
reason it is not checked out, for example because of a sparse checkout.

This makes it possible to use at least the 'git submodule' commands
which *read* the gitmodules configuration file without fully populating
the working tree.

Writing to .gitmodules will still require that the file is checked out,
so check for that before calling config_set_in_gitmodules_file_gently.

Add a similar check also in git-submodule.sh::cmd_add() to anticipate
the eventual failure of the "git submodule add" command when .gitmodules
is not safely writeable; this prevents the command from leaving the
repository in a spurious state (e.g. the submodule repository was cloned
but .gitmodules was not updated because
config_set_in_gitmodules_file_gently failed).

Moreover, since config_from_gitmodules() now accesses the global object
store, it is necessary to protect all code paths which call the function
against concurrent access to the global object store. Currently this
only happens in builtin/grep.c::grep_submodules(), so call
grep_read_lock() before invoking code involving
config_from_gitmodules().

Finally, add t7418-submodule-sparse-gitmodules.sh to verify that reading
from .gitmodules succeeds and that writing to it fails when the file is
not checked out.

NOTE: there is one rare case where this new feature does not work
properly yet: nested submodules without .gitmodules in their working
tree. This has been documented with a warning and a test_expect_failure
item in t7814, and in this case the current behavior is not altered: no
config is read.

Signed-off-by: Antonio Ospite <ao2@ao2.it>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

read_istream_pack_non_delta(): document input handling

Twice now we have scratched our heads about why the loose streaming code
needs the protection added by 692f0bc7ae (avoid infinite loop in
read_istream_loose, 2013-03-25), but the similar code in its pack
counterpart does not.

The short answer is that use_pack() will die before it lets us run out
of bytes. Note that this could mean reading garbage (including the
trailing hash) from the packfile in some cases of corruption, but that's
OK. zlib will notice and complain (and if not, certainly the end result
will not match the object hash we expect).

Let's leave a comment this time to document our findings.

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

ls-remote: pass heads/tags prefixes to transport

Unlike its arbitrary text patterns, the --heads and --tags
options to ls-remote are true prefixes. We can pass this
information to the transport code. If the v2 protocol is in
use, that will reduce the size of the ref advertisement.

Note that the test added here succeeds both before and after
the patch. This is an optimization, not a bug-fix; it's just
making sure we didn't break anything.

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

ls-remote: do not send ref prefixes for patterns

Since b4be74105f (ls-remote: pass ref prefixes when requesting a
remote's refs, 2018-03-15), "ls-remote foo" will pass "refs/heads/foo",
"refs/tags/foo", etc to the transport code in an attempt to let the
other side reduce the size of its advertisement.

Unfortunately this is not correct, as ls-remote patterns do not follow
the usual ref lookup rules, and are in fact tail-matched. So we could
find "refs/heads/foo" or "refs/heads/a/much/deeper/foo" or even
"refs/another/hierarchy/foo".

Since we can't pass a prefix and there's not yet a v2 extension for
matching wildcards, we must disable this feature to keep the same
behavior as v1.

Reported-by: Jon Simons <jon@jonsimons.org>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Adjust for 2.19.x series

* jk/detect-truncated-zlib-input
cat-file: handle streaming failures consistently
check_stream_sha1(): handle input underflow
t1450: check large blob in trailing-garbage test

cat-file: handle streaming failures consistently

There are three ways to convince cat-file to stream a blob:

- cat-file -p $blob

- cat-file blob $blob

- echo $batch | cat-file --batch

In the first two, we simply exit with the error code of
streaw_blob_to_fd(). That means that an error will cause us
to exit with "-1" (which we try to avoid) without printing
any kind of error message (which is confusing to the user).

Instead, let's match the third case, which calls die() on an
error. Unfortunately we cannot be more specific, as
stream_blob_to_fd() does not tell us whether the problem was
on reading (e.g., a corrupt object) or on writing (e.g.,
ENOSPC). That might be an opportunity for future work, but
for now we will at least exit with a sane message and exit
code.

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

check_stream_sha1(): handle input underflow

This commit fixes an infinite loop when fscking large
truncated loose objects.

The check_stream_sha1() function takes an mmap'd loose
object buffer and streams 4k of output at a time, checking
its sha1. The loop quits when we've output enough bytes (we
know the size from the object header), or when zlib tells us
anything except Z_OK or Z_BUF_ERROR.

The latter is expected because zlib may run out of room in
our 4k buffer, and that is how it tells us to process the
output and loop again.

But Z_BUF_ERROR also covers another case: one in which zlib
cannot make forward progress because it needs more _input_.
This should never happen in this loop, because though we're
streaming the output, we have the entire deflated input
available in the mmap'd buffer. But since we don't check
this case, we'll just loop infinitely if we do see a
truncated object, thinking that zlib is asking for more
output space.

It's tempting to fix this by checking stream->avail_in as
part of the loop condition (and quitting if all of our bytes
have been consumed). But that assumes that once zlib has
consumed the input, there is nothing left to do. That's not
necessarily the case: it may have read our input into its
internal state, but still have bytes to output.

Instead, let's continue on Z_BUF_ERROR only when we see the
case we're expecting: the previous round filled our output
buffer completely. If it didn't (and we still saw
Z_BUF_ERROR), we know something is wrong and should break
out of the loop.

The bug comes from commit f6371f9210 (sha1_file: add
read_loose_object() function, 2017-01-13), which
reimplemented some of the existing loose object functions.
So it's worth checking if this bug was inherited from any of
those. The answers seems to be no. The two obvious
candidates are both OK:

1. unpack_sha1_rest(); this doesn't need to loop on
Z_BUF_ERROR at all, since it allocates the expected
output buffer in advance (which we can't do since we're
explicitly streaming here)

2. check_object_signature(); the streaming path relies on
the istream interface, which uses read_istream_loose()
for this case. That function uses a similar "is our
output buffer full" check with Z_BUF_ERROR (which is
where I stole it from for this patch!)

Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t1450: check large blob in trailing-garbage test

Commit cce044df7f (fsck: detect trailing garbage in all
object types, 2017-01-13) added two tests of trailing
garbage in a loose object file: one with a commit and one
with a blob. The point of having two is that blobs would
follow a different code path that streamed the contents,
instead of loading it into a buffer as usual.

At the time, merely being a blob was enough to trigger the
streaming code path. But since 7ac4f3a007 (fsck: actually
fsck blob data, 2018-05-02), we now only stream blobs that
are actually large. So since then, the streaming code path
is not tested at all for this case.

We can restore the original intent of the test by tweaking
core.bigFileThreshold to make our small blob seem large.
There's no easy way to externally verify that we followed
the streaming code path, but I did check before/after using
a temporary debug statement.

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

mingw: fix isatty() after dup2()

Since a9b8a09c3c30 (mingw: replace isatty() hack, 2016-12-22), we handle
isatty() by special-casing the stdin/stdout/stderr file descriptors,
caching the return value. However, we missed the case where dup2()
overrides the respective file descriptor.

That poses a problem e.g. where the `show` builtin asks for a pager very
early, the `setup_pager()` function sets the pager depending on the
return value of `isatty()` and then redirects stdout. Subsequently,
`cmd_log_init_finish()` calls `setup_pager()` *again*. What should
happen now is that `isatty()` reports that stdout is *not* a TTY and
consequently stdout should be left alone.

Let's override dup2() to handle this appropriately.

This fixes https://github.com/git-for-windows/git/issues/1077

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

mingw: unset PERL5LIB by default

Git for Windows ships with its own Perl interpreter, and insists on
using it, so it will most likely wreak havoc if PERL5LIB is set before
launching Git.

Let's just unset that environment variables when spawning processes.

To make this feature extensible (and overrideable), there is a new
config setting `core.unsetenvvars` that allows specifying a
comma-separated list of names to unset before spawning processes.

Reported by Gabriel Fuhrmann.

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

config: move Windows-specific config settings into compat/mingw.c

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

config: allow for platform-specific core.* config settings

In the Git for Windows project, we have ample precendent for config
settings that apply to Windows, and to Windows only.

Let's formalize this concept by introducing a platform_core_config()
function that can be #define'd in a platform-specific manner.

This will allow us to contain platform-specific code better, as the
corresponding variables no longer need to be exported so that they can
be defined in environment.c and be set in config.c

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

config: rename `dummy` parameter to `cb` in git_default_config()

This is the convention elsewhere (and prepares for the case where we may
need to pass callback data).

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

mingw: reencode environment variables on the fly (UTF-16 <-> UTF-8)

On Windows, the authoritative environment is encoded in UTF-16. In Git
for Windows, we convert that to UTF-8 (because UTF-16 is *such* a
foreign idea to Git that its source code is unprepared for it).

Previously, out of performance concerns, we converted the entire
environment to UTF-8 in one fell swoop at the beginning, and upon
putenv() and run_command() converted it back.

Having a private copy of the environment comes with its own perils: when
a library used by Git's source code tries to modify the environment, it
does not really work (in Git for Windows' case, libcurl, see
https://github.com/git-for-windows/git/compare/bcad1e6d58^...bcad1e6d58^2
for a glimpse of the issues).

Hence, it makes our environment handling substantially more robust if we
switch to on-the-fly-conversion in `getenv()`/`putenv()` calls. Based
on an initial version in the MSVC context by Jeff Hostetler, this patch
makes it so.

Surprisingly, this has a *positive* effect on speed: at the time when
the current code was written, we tested the performance, and there were
*so many* `getenv()` calls that it seemed better to convert everything
in one go. In the meantime, though, Git has obviously been cleaned up a
bit with regards to `getenv()` calls so that the Git processes spawned
by the test suite use an average of only 40 `getenv()`/`putenv()` calls
over the process lifetime.

Speaking of the entire test suite: the total time spent in the
re-encoding in the current code takes about 32.4 seconds (out of 113
minutes runtime), whereas the code introduced in this patch takes only
about 8.2 seconds in total. Not much, but it proves that we need not be
concerned about the performance impact introduced by this patch.

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

t7800: fix quoting

When passing a command-line to call an external diff command to the
difftool, we must be prepared for paths containing special characters,
e.g. backslashes in the temporary directory's path on Windows.

This patch is needed in preparation for the next commit, which will
make the MinGW version of Git *not* rewrite TMP to use forward slashes
instead of backslashes.

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

worktree: rename is_worktree_locked to worktree_lock_reason

A function prefixed with 'is_' would be expected to return a boolean,
however this function returns a string.

Signed-off-by: Nickolai Belakovski <nbelakovski@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

worktree: update documentation for lock_reason and lock_reason_valid

Clarify that these fields are to be considered implementation details
and direct the reader to use the is_worktree_locked function to retrieve
said information.

Signed-off-by: Nickolai Belakovski <nbelakovski@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

index-pack tests: don't leave test repo dirty at end

Change a test added in 51054177b3 ("index-pack: detect local
corruption in collision check", 2017-04-01) so that the repository
isn't left dirty at the end.

Due to the caveats explained in 720dae5a19 ("config doc: elaborate on
fetch.fsckObjects security", 2018-07-27) even a "fetch" that fails
will write to the local object store, so let's copy the bit-error test
directory before running this test.

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

pack-objects tests: don't leave test .git corrupt at end

Change the pack-objects tests to not leave their .git directory
corrupt and the end.

In 2fca19fbb5 ("fix multiple issues with t5300", 2010-02-03) a comment
was added warning against adding any subsequent tests, but since
4614043c8f ("index-pack: use streaming interface for collision test on
large blobs", 2012-05-24) the comment has drifted away from the code,
mentioning two test, when we actually have three.

Instead of having this warning let's just create a new .git directory
specifically for these tests.

As an aside, it would be interesting to instrument the test suite to
run a "git fsck" at the very end (in "test_done"). That would have
errored before this change, and may find other issues #leftoverbits.

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

pack-objects test: modernize style

Modernize the quoting and indentation style of two tests added in
8685da4256 ("don't ever allow SHA1 collisions to exist by fetching a
pack", 2007-03-20), and of a subsequent one added in
4614043c8f ("index-pack: use streaming interface for collision test on
large blobs", 2012-05-24) which had copied the style of the first two.

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

sequencer: break out of loop explicitly

It came up in review [1, 2] that this non-idiomatic loop is a bit tricky.
When we find a space, we set `len = i`, which gives us the answer we are
looking for, but which also breaks out of the loop.

It turns out that this loop can confuse compilers as well. My copy of
gcc 7.3.0 realizes that we are essentially evaluating `(len + 1) < len`
and warns that the behavior is undefined if `len` is `INT_MAX`. (Because
the assignment `len = i` is guaranteed to decrease `len`, such undefined
behavior is not actually possible.)

Rewrite the loop to a more idiomatic variant which doesn't muck with
`len` in the loop body. That should help compilers and human readers
figure out what is going on here. But do note that we need to update
`len` since it is not only used just after this loop (where we could
have used `i` directly), but also later in this function.

While at it, reduce the scope of `i`.

[1] https://public-inbox.org/git/CAPig+cQbG2s-LrAo9+7C7=dXifbWFJ3SzuNa-QePHDk7egK=jg@mail.gmail.com/

[2] https://public-inbox.org/git/CAPig+cRjU6niXpT2FrDWZ0x1HmGf1ojVZj3uk2qXEGe-S7i_HQ@mail.gmail.com/

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Seventh batch for 2.20

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

Merge branch 'jk/uploadpack-packobjectshook-fix'

Code clean-up that results in a small bugfix.

* jk/uploadpack-packobjectshook-fix:
upload-pack: fix broken if/else chain in config callback

Merge branch 'uk/merge-subtree-doc-update'

Belated documentation update to adjust to a new world order that
happened a yew years ago.

* uk/merge-subtree-doc-update:
howto/using-merge-subtree: mention --allow-unrelated-histories

Merge branch 'cb/compat-mmap-is-private-read-only'

Code tightening.

* cb/compat-mmap-is-private-read-only:
compat: make sure git_mmap is not expected to write

Merge branch 'dl/mergetool-gui-option'

"git mergetool" learned to take the "--[no-]gui" option, just like
"git difftool" does.

* dl/mergetool-gui-option:
doc: document diff/merge.guitool config keys
completion: support `git mergetool --[no-]gui`
mergetool: accept -g/--[no-]gui as arguments

Merge branch 'js/mingw-load-sys-dll'

The way DLLs are loaded on the Windows port has been improved.

* js/mingw-load-sys-dll:
mingw: load system libraries the recommended way

Merge branch 'js/mingw-getcwd'

The way the Windows port figures out the current directory has been
improved.

* js/mingw-getcwd:
mingw: fix getcwd when the parent directory cannot be queried
mingw: ensure `getcwd()` reports the correct case

Merge branch 'cb/khash-maybe-unused-function'

Build fix.

* cb/khash-maybe-unused-function:
khash: silence -Wunused-function for delta-islands
commit-slabs: move MAYBE_UNUSED out

Merge branch 'jc/cocci-preincr'

Code cleanup.

* jc/cocci-preincr:
fsck: s/++i > 1/i++/
cocci: simplify "if (++u > 1)" to "if (u++)"

Merge branch 'ss/rename-tests'

Reorganize some tests and rename them; "ls t/" now gives a better
overview of what is tested for these scripts than before.

* ss/rename-tests:
t7501: rename commit test to comply with naming convention
t7500: rename commit tests script to comply with naming convention
t7502: rename commit test script to comply with naming convention
t7509: cleanup description and filename
t2000: rename and combine checkout clash tests

Merge branch 'ah/doc-updates'

Doc updates.

* ah/doc-updates:
doc: fix formatting in git-update-ref
doc: fix indentation of listing blocks in gitweb.conf.txt
doc: fix descripion for 'git tag --format'
doc: fix inappropriate monospace formatting
doc: fix ASCII art tab spacing
doc: clarify boundaries of 'git worktree list --porcelain'

Merge branch 'ds/reachable'

Trivial bugfix.

* ds/reachable:
commit-reach: fix cast in compare_commits_by_gen()

Merge branch 'jc/receive-deny-current-branch-fix'

The receive.denyCurrentBranch=updateInstead codepath kicked in even
when the push should have been rejected due to other reasons, such
as it does not fast-forward or the update-hook rejects it, which
has been corrected.

* jc/receive-deny-current-branch-fix:
receive: denyCurrentBranch=updateinstead should not blindly update

Merge branch 'ds/ci-commit-graph-and-midx'

One of our CI tests to run with "unusual/experimental/random"
settings now also uses commit-graph and midx.

* ds/ci-commit-graph-and-midx:
ci: add optional test variables

Merge branch 'jk/unused-function'

Developer support.

* jk/unused-function:
config.mak.dev: enable -Wunused-function

Merge branch 'cb/remove-dead-init'

Code clean-up.

* cb/remove-dead-init:
multi-pack-index: avoid dead store for struct progress
unpack-trees: avoid dead store for struct progress

Merge branch 'js/diff-notice-has-drive-prefix'

Under certain circumstances, "git diff D:/a/b/c D:/a/b/d" on
Windows would strip initial parts from the paths because they
were not recognized as absolute, which has been corrected.

* js/diff-notice-has-drive-prefix:
diff: don't attempt to strip prefix from absolute Windows paths

Merge branch 'ot/ref-filter-plug-leaks'

Plugging a handful of memory leaks in the ref-filter codepath.

* ot/ref-filter-plug-leaks:
ref-filter: free item->value and item->value->s
ls-remote: release memory instead of UNLEAK
ref-filter: free memory from used_atom

Merge branch 'ds/reachable-first-parent-fix'

Correct performance regression in commit ancestry computation when
generation numbers are involved.

* ds/reachable-first-parent-fix:
commit-reach: fix first-parent heuristic

Merge branch 'rj/header-guards'

Code clean-up.

* rj/header-guards:
headers: normalize the spelling of some header guards

Merge branch 'jk/test-tool-help'

Developer support.

* jk/test-tool-help:
test-tool: show tool list on error

Merge branch 'sg/doc-show-branch-typofix'

Docfix.

* sg/doc-show-branch-typofix:
doc: fix small typo in git show-branch

Merge branch 'sb/submodule-helper-remove-cruft'

Code clean-up.

* sb/submodule-helper-remove-cruft:
builtin/submodule--helper: remove debugging leftover tracing

Merge branch 'js/pack-objects-mutex-init-fix'

A mutex used in "git pack-objects" were not correctly initialized
and this caused "git repack" to dump core on Windows.

* js/pack-objects-mutex-init-fix:
pack-objects (mingw): initialize `packing_data` mutex in the correct spot
pack-objects (mingw): demonstrate a segmentation fault with large deltas
pack-objects: fix typo 'detla' -> 'delta'

Merge branch 'tq/branch-style-fix'

Code clean-up.

* tq/branch-style-fix:
branch: trivial style fix

Merge branch 'tq/branch-create-wo-branch-get'

Code clean-up.

* tq/branch-create-wo-branch-get:
builtin/branch.c: remove useless branch_get

Merge branch 'bc/hash-transition-part-15'

More codepaths are moving away from hardcoded hash sizes.

* bc/hash-transition-part-15:
rerere: convert to use the_hash_algo
submodule: make zero-oid comparison hash function agnostic
apply: rename new_sha1_prefix and old_sha1_prefix
apply: replace hard-coded constants
tag: express constant in terms of the_hash_algo
transport: use parse_oid_hex instead of a constant
upload-pack: express constants in terms of the_hash_algo
refs/packed-backend: express constants using the_hash_algo
packfile: express constants in terms of the_hash_algo
pack-revindex: express constants in terms of the_hash_algo
builtin/fetch-pack: remove constants with parse_oid_hex
builtin/mktree: remove hard-coded constant
builtin/repack: replace hard-coded constants
pack-bitmap-write: use GIT_MAX_RAWSZ for allocation
object_id.cocci: match only expressions of type 'struct object_id'

Merge branch 'sb/strbuf-h-update'

Code clean-up to serve as a BCP example.

* sb/strbuf-h-update:
strbuf.h: format according to coding guidelines

Merge branch 'jk/run-command-notdot'

The implementation of run_command() API on the UNIX platforms had a
bug that caused a command not on $PATH to be found in the current
directory.

* jk/run-command-notdot:
run-command: mark path lookup errors with ENOENT

Merge branch 'tb/filter-alternate-refs'

Test fix.

* tb/filter-alternate-refs:
t5410: use longer path for sample script
Documentation/config.txt: fix typo in core.alternateRefsCommand