doc: revisions: give headings for the two and three dot notations
While there, also break out the other shorthand notations and
add a title for the revision range summary (which also appears
in git-rev-parse, so keep it mixed case).
We do not quote the notation within the headings as the asciidoc ->
docbook -> groff man viewer toolchain, particularly the docbook-groff
step, does not cope with two font changes, failing to return the heading
font to bold after the quotation of the notation.
Signed-off-by: Philip Oakley <philipoakley@iee.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
When "git rebase" tries to compare set of changes on the updated
upstream and our own branch, it computes patch-id for all of these
changes and attempts to find matches. This has been optimized by
lazily computing the full patch-id (which is expensive) to be
compared only for changes that touch the same set of paths.
* kw/patch-ids-optim:
rebase: avoid computing unnecessary patch IDs
patch-ids: add flag to create the diff patch id using header only data
patch-ids: replace the seen indicator with a commit pointer
patch-ids: stop using a hand-rolled hashmap implementation
"git mv dir non-existing-dir/" did not work in some environments
the same way as existing mainstream platforms. The code now moves
"dir" to "non-existing-dir", without relying on rename("A", "B/")
that strips the trailing slash of '/'.
* js/mv-dir-to-new-directory:
git mv: do not keep slash in `git mv dir non-existing-dir/`
* jk/trace-fixup:
trace: do not fall back to stderr
write_or_die: drop write_or_whine_pipe()
trace: disable key after write error
trace: correct variable name in write() error message
trace: cosmetic fixes for error messages
trace: use warning() for printing trace errors
trace: stop using write_or_whine_pipe()
trace: handle NULL argument in trace_disable()
"import-tars" fast-import script (in contrib/) used to ignore a
hardlink target and replaced it with an empty file, which has been
corrected to record the same blob as the other file the hardlink is
shared with.
* js/import-tars-hardlinks:
import-tars: support hard links
"git difftool <paths>..." started in a subdirectory failed to
interpret the paths relative to that directory, which has been
fixed.
* jk/difftool-in-subdir:
difftool: use Git::* functions instead of passing around state
difftool: avoid $GIT_DIR and $GIT_WORK_TREE
difftool: fix argument handling in subdirs
Merge branch 'jk/reset-ident-time-per-commit' into maint
Not-so-recent rewrite of "git am" that started making internal
calls into the commit machinery had an unintended regression, in
that no matter how many seconds it took to apply many patches, the
resulting committer timestamp for the resulting commits were all
the same.
* jk/reset-ident-time-per-commit:
am: reset cached ident date for each patch
The `rebase` family of Git commands avoid applying patches that were
already integrated upstream. They do that by using the revision walking
option that computes the patch IDs of the two sides of the rebase
(local-only patches vs upstream-only ones) and skipping those local
patches whose patch ID matches one of the upstream ones.
In many cases, this causes unnecessary churn, as already the set of
paths touched by a given commit would suffice to determine that an
upstream patch has no local equivalent.
This hurts performance in particular when there are a lot of upstream
patches, and/or large ones.
Therefore, let's introduce the concept of a "diff-header-only" patch ID,
compare those first, and only evaluate the "full" patch ID lazily.
Please note that in contrast to the "full" patch IDs, those
"diff-header-only" patch IDs are prone to collide with one another, as
adjacent commits frequently touch the very same files. Hence we now
have to be careful to allow multiple hash entries with the same hash.
We accomplish that by using the hashmap_add() function that does not even
test for hash collisions. This also allows us to evaluate the full patch ID
lazily, i.e. only when we found commits with matching diff-header-only
patch IDs.
We add a performance test that demonstrates ~1-6% improvement. In
practice this will depend on various factors such as how many upstream
changes and how big those changes are along with whether file system
caches are cold or warm. As Git's test suite has no way of catching
performance regressions, we also add a regression test that verifies
that the full patch ID computation is skipped when the diff-header-only
computation suffices.
Signed-off-by: Kevin Willford <kcwillford@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit message is long and has lots of background and
numbers. The summary is: the current default of 250 doesn't
save much space, and costs CPU. It's not a good tradeoff.
Read on for details.
The "--aggressive" flag to git-gc does three things:
1. use "-f" to throw out existing deltas and recompute from
scratch
2. use "--window=250" to look harder for deltas
3. use "--depth=250" to make longer delta chains
Items (1) and (2) are good matches for an "aggressive"
repack. They ask the repack to do more computation work in
the hopes of getting a better pack. You pay the costs during
the repack, and other operations see only the benefit.
Item (3) is not so clear. Allowing longer chains means fewer
restrictions on the deltas, which means potentially finding
better ones and saving some space. But it also means that
operations which access the deltas have to follow longer
chains, which affects their performance. So it's a tradeoff,
and it's not clear that the tradeoff is even a good one.
The existing "250" numbers for "--aggressive" come
originally from this thread:
So when I said "--depth=250 --window=250", I chose those
numbers more as an example of extremely aggressive
packing, and I'm not at all sure that the end result is
necessarily wonderfully usable. It's going to save disk
space (and network bandwidth - the delta's will be re-used
for the network protocol too!), but there are definitely
downsides too, and using long delta chains may
simply not be worth it in practice.
There are some numbers in that thread, but they're mostly
focused on the improved window size, and measure the
improvement from --depth=250 and --window=250 together.
E.g.:
talks about the improved run-time of "git-blame", which
comes from the reduced pack size. But most of that reduction
is coming from --window=250, whereas most of the extra costs
come from --depth=250. There's a link in that thread showing
that increasing the depth beyond 50 doesn't seem to help
much with the size:
we have more numbers, with the conclusion that going past 50
does not help size much, and hurts the speed of normal
operations.
So from that, we might guess that 50 is actually a sweet
spot, even for aggressive, if we interpret aggressive to
"spend time now to make a better pack". It is not clear that
"--depth=250" is actually a better pack. It may be slightly
_smaller_, but it carries a run-time penalty.
Here are some more recent timings I did to verify that. They
show three things:
- the size of the resulting pack (so disk saved to store,
bandwidth saved on clones/fetches)
- the cost of "rev-list --objects --all", which shows the
effect of the delta chains on trees (commits typically
don't delta, and the command doesn't touch the blobs at
all)
- the cost of "log -Sfoo", which will additionally access
each blob
All cases were repacked with "git repack -adf --depth=$d
--window=250" (so basically, what would happen if we tweaked
the "gc --aggressive" default depth).
The timings are all wall-clock best-of-3. The machine itself
has plenty of RAM compared to the repositories (which is
probably typical of most workstations these days), so we're
really measuring CPU usage, as the whole thing will be in
disk cache after the first run.
The core.deltaBaseCacheLimit is at its default of 96MiB.
It's possible that tweaking it would have some impact on the
tests, as some of them (especially "log -S" on a large repo)
are likely to overflow that. But bumping that carries a
run-time memory cost, so for these tests, I focused on what
we could do just with the on-disk pack tradeoffs.
Each test is done for four depths: 250 (the current value),
50 (the current default that tested well previously), 100
(to show something on the larger side, which previous tests
showed was not a good tradeoff), and 10 (the very old
default, which previous tests showed was worse than 50).
You can see that that the CPU savings for regular operations improves as we
decrease the depth. The savings are less for "rev-list" on a smaller repository
than they are for blob-accessing operations, or even rev-list on a larger
repository. This may mean that a larger delta cache would help (though setting
core.deltaBaseCacheLimit by itself doesn't).
But we can also see that the space savings are not that great as the depth goes
higher. Saving 5-10% between 10 and 50 is probably worth the CPU tradeoff.
Saving 1% to go from 50 to 100, or another 0.5% to go from 100 to 250 is
probably not.
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git am -3" calls "git merge-recursive" when it needs to fall back
to a three-way merge; this call has been turned into an internal
subroutine call instead of spawning a separate subprocess.
* js/am-3-merge-recursive-direct:
merge-recursive: flush output buffer even when erroring out
merge_trees(): ensure that the callers release output buffer
merge-recursive: offer an option to retain the output in 'obuf'
merge-recursive: write the commit title in one go
merge-recursive: flush output buffer before printing error messages
am -3: use merge_recursive() directly again
merge-recursive: switch to returning errors instead of dying
merge-recursive: handle return values indicating errors
merge-recursive: allow write_tree_from_memory() to error out
merge-recursive: avoid returning a wholesale struct
merge_recursive: abort properly upon errors
prepare the builtins for a libified merge_recursive()
merge-recursive: clarify code in was_tracked()
die(_("BUG")): avoid translating bug messages
die("bug"): report bugs consistently
t5520: verify that `pull --rebase` shows the helpful advice when failing
"git push --force-with-lease" already had enough logic to allow
ensuring that such a push results in creation of a ref (i.e. the
receiving end did not have another push from sideways that would be
discarded by our force-pushing), but didn't expose this possibility
to the users. It does so now.
* jk/push-force-with-lease-creation:
t5533: make it pass on case-sensitive filesystems
push: allow pushing new branches with --force-with-lease
push: add shorthand for --force-with-lease branch creation
Documentation/git-push: fix placeholder formatting
Not-so-recent rewrite of "git am" that started making internal
calls into the commit machinery had an unintended regression, in
that no matter how many seconds it took to apply many patches, the
resulting committer timestamp for the resulting commits were all
the same.
* jk/reset-ident-time-per-commit:
am: reset cached ident date for each patch
The API documentation for hashmap was unclear if hashmap_entry
can be safely discarded without any other consideration. State
that it is safe to do so.
* jc/hashmap-doc-init:
hashmap: clarify that hashmap_entry can safely be discarded
FreeBSD can lie when asked mtime of a directory, which made the
untracked cache code to fall back to a slow-path, which in turn
caused tests in t7063 to fail because it wanted to verify the
behaviour of the fast-path.
* nd/fbsd-lazy-mtime:
t7063: work around FreeBSD's lazy mtime update feature
Merge branch 'jk/diff-do-not-reuse-wtf-needs-cleaning' into maint
There is an optimization used in "git diff $treeA $treeB" to borrow
an already checked-out copy in the working tree when it is known to
be the same as the blob being compared, expecting that open/mmap of
such a file is faster than reading it from the object store, which
involves inflating and applying delta. This however kicked in even
when the checked-out copy needs to go through the convert-to-git
conversion (including the clean filter), which defeats the whole
point of the optimization. The optimization has been disabled when
the conversion is necessary.
* jk/diff-do-not-reuse-wtf-needs-cleaning:
diff: do not reuse worktree files that need "clean" conversion
Merge branch 'pm/build-persistent-https-with-recent-go' into maint
The build procedure for "git persistent-https" helper (in contrib/)
has been updated so that it can be built with more recent versions
of Go.
* pm/build-persistent-https-with-recent-go:
contrib/persistent-https: use Git version for build label
contrib/persistent-https: update ldflags syntax for Go 1.7+
Merge branch 'da/subtree-2.9-regression' into maint
"git merge" in Git v2.9 was taught to forbid merging an unrelated
lines of history by default, but that is exactly the kind of thing
the "--rejoin" mode of "git subtree" (in contrib/) wants to do.
"git subtree" has been taught to use the "--allow-unrelated-histories"
option to override the default.
Users of the parse_options_concat() API function need to allocate
extra slots in advance and fill them with OPT_END() when they want
to decide the set of supported options dynamically, which makes the
code error-prone and hard to read. This has been corrected by tweaking
the API to allocate and return a new copy of "struct option" array.
* jk/parse-options-concat:
parse_options: allocate a new array when concatenating
Existing autoconf generated test for the need to link with pthread
library did not check all the functions from pthread libraries;
recent FreeBSD has some functions in libc but not others, and we
mistakenly thought linking with libc is enough when it is not.
* ew/autoconf-pthread:
configure.ac: stronger test for pthread linkage
On OSX `wc` prefixes the output of numbers with whitespace, such
that the `commit_count` would be "SP <NUMBER>". When using that in
git submodule update --init --depth=$commit_count
the depth would be empty and the number is interpreted as the
pathspec. Fix this by not using `wc` and rather instruct rev-list
to count.
Another way to fix this is to remove the `=` sign after the
`--depth` argument as then we are allowed to have more than just one
whitespace between `--depth` and the actual number. Prefer the
solution of rev-list counting as that is expected to be slightly
faster and more self-contained within Git.
Reported-by: Lars Schneider <larsxschneider@gmail.com> Helped-by: Junio C Hamano <gitster@pobox.com>, Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Avoid waking up the readers for unnecessary context switches for
each line of header data being written, as all the headers are
written in short succession.
It is unlikely any HTTP/1.x server would want to read a CGI
response one-line-at-a-time and trickle each to the client.
Instead, I'd expect HTTP servers want to minimize syscall and
TCP/IP framing overhead by trying to send all of its response
headers in a single syscall or even combining the headers and
first chunk of the body with MSG_MORE or writev.
Verified by strace-ing response parsing on the CGI side.
Signed-off-by: Eric Wong <e@80x24.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
submodule--helper: use parallel processor correctly
When developing another patch series I had a temporary state in
which git-clone would segfault, when the call was prepared in
prepare_to_clone_next_submodule. This lead to the call failing,
i.e. in `update_clone_task_finished` the task was scheduled to be
tried again. The second call to prepare_to_clone_next_submodule
would return 0, as the segfaulted clone did create the .git file
already, such that was not considered to need to be cloned again. I
was seeing the "BUG: ce was a submodule before?\n" message, which
was the correct behavior at the time as my local code was
buggy. When trying to debug this failure, I tried to use printing
messages into the strbuf that is passed around, but these messages
were never printed as the die(..) doesn't flush the `err` strbuf.
When implementing the die() in 665b35ecc (2016-06-09, "submodule--helper:
initial clone learns retry logic"), I considered this condition to be
a severe condition, which should lead to an immediate abort as we do not
trust ourselves any more. However the queued messages in `err` are valuable
so let's not toss them out by immediately dying, but a graceful return.
Another thing to note: The error message itself was misleading. A return
value of 0 doesn't indicate the passed in `ce` is not a submodule any more,
but just that we do not consider cloning it any more.
Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
completion: add completion for --submodule=* diff option
Teach git-completion.bash to complete --submodule= for git commands
which take diff options. Also teach completion for git-log to support
--diff-algorithms as well.
Signed-off-by: Jacob Keller <jacob.keller@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
commit-slab.h: avoid duplicated global static variables
The gigantic define_commit_slab() macro repeats the definition of a
static variable that occurs earlier in the macro text. The purpose of
the repeated definition at the end of the macro is that it takes the
semicolon that occurs where the macro is used.
We cannot just remove the first definition of the variable because it
is referenced elsewhere in the macro text, and defining the macro later
would produce undefined identifier errors. We cannot have a "forward"
declaration, either. (This works only with "extern" global variables.)
The solution is to use a declaration of a struct that is already defined
earlier. This language construct can serve the same purpose as the
duplicated static variable definition, but without the confusion.
Signed-off-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
config.c: avoid duplicated global static variables
Repeating the definition of a static variable seems to be valid in C.
Nevertheless, it is bad style because it can cause confusion, definitely
when it becomes necessary to change the type.
d64ec16 (git config: reorganize to use parseopt, 2009-02-21) added two
static variables near the top of the file config.c without removing the
definitions of the two variables that occurs later in the file.
The two variables were needed earlier in the file in the newly
introduced parseopt structure. These references were removed later in d0e08d6 (config: fix parsing of "git config --get-color some.key -1",
2014-11-20).
Remove the redundant, younger, definitions near the top of the file and
keep the original definitions that occur later.
Signed-off-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
The API documentation for hashmap was unclear if hashmap_entry
can be safely discarded without any other consideration. State
that it is safe to do so.
* jc/hashmap-doc-init:
hashmap: clarify that hashmap_entry can safely be discarded
The build procedure learned PAGER_ENV knob that lists what default
environment variable settings to export for popular pagers. This
mechanism is used to tweak the default settings to MORE on FreeBSD.
* ew/build-time-pager-tweaks:
pager: move pager-specific setup into the build
FreeBSD can lie when asked mtime of a directory, which made the
untracked cache code to fall back to a slow-path, which in turn
caused tests in t7063 to fail because it wanted to verify the
behaviour of the fast-path.
* nd/fbsd-lazy-mtime:
t7063: work around FreeBSD's lazy mtime update feature
An entry "git log --decorate" for the tip of the current branch is
shown as "HEAD -> name" (where "name" is the name of the branch);
paint the arrow in the same color as "HEAD", not in the color for
commits.
* nd/log-decorate-color-head-arrow:
log: decorate HEAD -> branch with the same color for arrow and HEAD
The t3700 test about "add --chmod=-x" have been made a bit more
robust and generally cleaned up.
* ib/t3700-add-chmod-x-updates:
t3700: add a test_mode_in_index helper function
t3700: merge two tests into one
t3700: remove unwanted leftover files before running new tests
"git pack-objects" has a few options that tell it not to pack
objects found in certain packfiles, which require it to scan .idx
files of all available packs. The codepaths involved in these
operations have been optimized for a common case of not having any
non-local pack and/or any .kept pack.
* jk/pack-objects-optim:
pack-objects: compute local/ignore_pack_keep early
pack-objects: break out of want_object loop early
find_pack_entry: replace last_found_pack with MRU cache
add generic most-recently-used list
sha1_file: drop free_pack_by_name
t/perf: add tests for many-pack scenarios
"git difftool <paths>..." started in a subdirectory failed to
interpret the paths relative to that directory, which has been
fixed.
* jk/difftool-in-subdir:
difftool: use Git::* functions instead of passing around state
difftool: avoid $GIT_DIR and $GIT_WORK_TREE
difftool: fix argument handling in subdirs
Tests for "git svn" have been taught to reuse the lib-httpd test
infrastructure when testing the subversion integration that
interacts with subversion repositories served over the http://
protocol.
* ew/git-svn-http-tests:
git svn: migrate tests to use lib-httpd
t/t91*: do not say how to avoid the tests
Merge branch 'rs/submodule-config-code-cleanup' into maint
Code cleanup.
* rs/submodule-config-code-cleanup:
submodule-config: fix test binary crashing when no arguments given
submodule-config: combine early return code into one goto
submodule-config: passing name reference for .gitmodule blobs
submodule-config: use explicit empty string instead of strbuf in config_from()
* nd/test-helpers:
t/test-lib.sh: fix running tests with --valgrind
Makefile: use VCSSVN_LIB to refer to svn library
Makefile: drop extra dependencies for test helpers