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Author SHA1 Message Date
Patrick Steinhardt
ade1552598 t0000: fix test if run with TEST_OUTPUT_DIRECTORY
Testcases in t0000 are quite special given that they many of them run
nested testcases to verify that testing functionality itself works as
expected. These nested testcases are realized by writing a new ad-hoc
test script which again sources test-lib.sh, where the new script is
created in a nested subdirectory located beneath the current trash
directory. We then execute the new test script with the nested
subdirectory as current working directory and explicitly re-export
TEST_OUTPUT_DIRECTORY to point to that directory.

While this works as expected in the general case, it falls apart when
the developer has TEST_OUTPUT_DIRECTORY explicitly defined either via
the environment or via config.mak and runs "make test". In that case,
test-lib.sh will clobber the value that we've just carefully set up to
instead contain what the developer has defined. As a result, the
TEST_OUTPUT_DIRECTORY continues to point at the root output directory,
not at the nested one.

This issue causes breakage in the 'test_atexit is run' test case: the
nested test case writes files into "../../", which is assumed to be the
parent's trash directory. But because TEST_OUTPUT_DIRECTORY already
points to to the root output directory, we instead end up writing those
files outside of the output directory. The parent test case will then
try to check whether those files still exist in its own trash directory,
which thus must fail now.

Fix the issue by adding a new TEST_OUTPUT_DIRECTORY_OVERRIDE variable.
If set, then we'll always override the TEST_OUTPUT_DIRECTORY with its
value after sourcing GIT-BUILD-OPTIONS.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-20 09:19:02 -07:00
Taylor Blau
88617d11f9 multi-pack-index: fix potential segfault without sub-command
Since cd57bc41bb (builtin/multi-pack-index.c: display usage on
unrecognized command, 2021-03-30) we have used a "usage" label to avoid
having two separate callers of usage_with_options (one when no arguments
are given, and another for unrecognized sub-commands).

But the first caller has been broken since cd57bc41bb, since it will
happily jump to usage without arguments, and then pass argv[0] to the
"unrecognized subcommand" error.

Many compilers will save us from a segfault here, but the end result is
ugly, since it mentions an unrecognized subcommand when we didn't even
pass one, and (on GCC) includes "(null)" in its output.

Move the "usage" label down past the error about unrecognized
subcommands so that it is only triggered when it should be. While we're
at it, bulk up our test coverage in this area, too.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-19 15:24:01 -07:00
Han-Wen Nienhuys
c510928a25 refs/debug: quote prefix
This makes the empty prefix ("") stand out better.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-19 14:32:34 -07:00
Jeff King
ac223c4047 t0000: clear GIT_SKIP_TESTS before running sub-tests
In t0000, we run several fake "sub-test" suites to verify the behavior
of the test suite. But because we don't clear the parent environment
completely, the sub-tests can be fooled by variables meant for the
parent. For example:

  GIT_SKIP_TESTS=t1234 ./t0000-basic.sh

fails when a sub-test expects its fake t1234 to actually run. This
particular pattern is unlikely in practice; we're running a single
script, and there is no t1234 in the real test suite anyway (not yet, at
least). A more real-world example is:

  GIT_SKIP_TESTS=t[^0]* make test

to run only the t0* tests.

The fix is conceptually simple: we should clear the GIT_SKIP_TESTS
variable when running the sub-tests, because its contents (if any) will
be meant for the main test suite. This is easy to do centrally in our
sub-test helper.

But there's a catch: some of our tests do set GIT_SKIP_TESTS
intentionally to test the feature. We need to allow them to continue to
set it, but clear it for all the other tests. And the sub-test helper
can't tell if the GIT_SKIP_TESTS it sees is from a test or not. We can
handle this by adding a new option to the helper to let callers specify
the skip list.

I considered adding a more general "--eval" option to let callers set up
the env for the sub-test however they like. That would cover this case
and possible future ones. But the quoting gets awkward for the callers
(since we're now 2 layers deep in evals!), so I went with the simpler
more specific solution.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-19 13:26:00 -07:00
Ævar Arnfjörð Bjarmason
64f0109f17 test-lib-functions: use test-tool for [de]packetize()
The shell+perl "[de]packetize()" helper functions were added in
4414a15002 (t/lib-git-daemon: add network-protocol helpers,
2018-01-24), and around the same time we added the "pkt-line" helper
in 74e7002961 (test-pkt-line: introduce a packet-line test helper,
2018-03-14).

For some reason it seems we've mostly used the shell+perl version
instead of the helper since then. There were discussions around
88124ab263 (test-lib-functions: make packetize() more efficient,
2020-03-27) and cacae4329f (test-lib-functions: simplify packetize()
stdin code, 2020-03-29) to improve them and make them more efficient.

There was one good reason to do so, we needed an equivalent of
"test-tool pkt-line pack", but that command wasn't capable of handling
input with "\n" (a feature) or "\0" (just because it happens to be
printf-based under the hood).

Let's add a "pkt-line-raw" helper for that, and expose is at a
packetize_raw() to go with the existing packetize() on the shell
level, this gives us the smallest amount of change to the tests
themselves.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-19 11:53:50 -07:00
Junio C Hamano
daab8a564f The fifth batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-16 17:42:53 -07:00
Junio C Hamano
8e62a85352 Merge branch 'ds/gender-neutral-doc'
Update the documentation not to assume users are of certain gender
and adds to guidelines to do so.

* ds/gender-neutral-doc:
  *: fix typos
  comments: avoid using the gender of our users
  doc: avoid using the gender of other people
2021-07-16 17:42:53 -07:00
Junio C Hamano
8721e2eaed Merge branch 'jt/partial-clone-submodule-1'
Prepare the internals for lazily fetching objects in submodules
from their promisor remotes.

* jt/partial-clone-submodule-1:
  promisor-remote: teach lazy-fetch in any repo
  run-command: refactor subprocess env preparation
  submodule: refrain from filtering GIT_CONFIG_COUNT
  promisor-remote: support per-repository config
  repository: move global r_f_p_c to repo struct
2021-07-16 17:42:53 -07:00
Junio C Hamano
bd4232fac3 Merge branch 'ab/struct-init'
Code cleanup around struct_type_init() functions.

* ab/struct-init:
  string-list.h users: change to use *_{nodup,dup}()
  string-list.[ch]: add a string_list_init_{nodup,dup}()
  dir.[ch]: replace dir_init() with DIR_INIT
  *.c *_init(): define in terms of corresponding *_INIT macro
  *.h: move some *_INIT to designated initializers
2021-07-16 17:42:53 -07:00
Junio C Hamano
832a239b72 Merge branch 'dd/test-stdout-count-lines'
Tiny test clean-up.

* dd/test-stdout-count-lines:
  t6402: preserve git exit status code
  t6400: preserve git ls-files exit status code
  test-lib-functions: introduce test_stdout_line_count
2021-07-16 17:42:52 -07:00
Junio C Hamano
c4670b8a8d Merge branch 'hn/refs-test-cleanup'
Test clean-up.

* hn/refs-test-cleanup:
  t7509: avoid direct file access for writing CHERRY_PICK_HEAD
  t1415: avoid direct filesystem access for writing refs
2021-07-16 17:42:52 -07:00
Junio C Hamano
a91e0bb833 Merge branch 'rs/khash-alloc-cleanup'
Code clean-up.

* rs/khash-alloc-cleanup:
  khash: clarify that allocations never fail
2021-07-16 17:42:52 -07:00
Junio C Hamano
8eb90d385c Merge branch 'ar/help-micro-cleanup'
Tiny code clean-up.

* ar/help-micro-cleanup:
  help: convert git_cmd to page in one place
2021-07-16 17:42:51 -07:00
Junio C Hamano
f90efd9981 Merge branch 'ar/submodule-helper-include-cleanup'
Code clean-up.

* ar/submodule-helper-include-cleanup:
  submodule--helper: remove redundant include
2021-07-16 17:42:51 -07:00
Junio C Hamano
cdeabf513a Merge branch 'ab/bundle-updates'
Code clean-up and leak plugging in "git bundle".

* ab/bundle-updates:
  bundle: remove "ref_list" in favor of string-list.c API
  bundle.c: use a temporary variable for OIDs and names
  bundle cmd: stop leaking memory from parse_options_cmd_bundle()
2021-07-16 17:42:49 -07:00
Junio C Hamano
f0ade787ac Merge branch 'hn/refs-iterator-peel-returns-boolean'
Tiny API tweak.

* hn/refs-iterator-peel-returns-boolean:
  refs: make explicit that ref_iterator_peel returns boolean
2021-07-16 17:42:49 -07:00
Junio C Hamano
3cc43bff9c Merge branch 'ab/mktag-tests'
Fill test gaps.

* ab/mktag-tests:
  mktag tests: test fast-export
  mktag tests: test for-each-ref
  mktag tests: test update-ref and reachable fsck
  mktag tests: test hash-object --literally and unreachable fsck
  mktag tests: invert --no-strict test
  mktag tests: parse out options in helper
2021-07-16 17:42:48 -07:00
Junio C Hamano
1fb3445658 Merge branch 'ab/show-branch-tests'
Fill test gaps.

* ab/show-branch-tests:
  show-branch tests: add missing tests
  show-branch: don't <COLOR></RESET> for space characters
  show-branch tests: modernize test code
  show-branch tests: rename the one "show-branch" test file
2021-07-16 17:42:48 -07:00
Junio C Hamano
b2fc822629 Merge branch 'ab/fetch-negotiate-segv-fix'
Code recently added to support common ancestry negotiation during
"git push" did not sanity check its arguments carefully enough.

* ab/fetch-negotiate-segv-fix:
  fetch: fix segfault in --negotiate-only without --negotiation-tip=*
  fetch: document the --negotiate-only option
  send-pack.c: move "no refs in common" abort earlier
2021-07-16 17:42:48 -07:00
Junio C Hamano
368cab75c1 Merge branch 'ab/make-delete-on-error'
Use ".DELETE_ON_ERROR" pseudo target to simplify our Makefile.

* ab/make-delete-on-error:
  Makefile: add and use the ".DELETE_ON_ERROR" flag
2021-07-16 17:42:47 -07:00
Junio C Hamano
a93c6fd677 Merge branch 'ew/mmap-failures'
Error message update.

* ew/mmap-failures:
  xmmap: inform Linux users of tuning knobs on ENOMEM
2021-07-16 17:42:47 -07:00
Junio C Hamano
fba551379e Merge branch 'js/config-mak-windows-pcre-fix'
Whitespace fix.

* js/config-mak-windows-pcre-fix:
  config.mak.uname: PCRE1 cleanup
2021-07-16 17:42:47 -07:00
Junio C Hamano
bc34e5227b Merge branch 'js/gfw-system-config-loc-fix'
Update the location of system-side configuration file on Windows.

* js/gfw-system-config-loc-fix:
  config: normalize the path of the system gitconfig
  cmake(windows): set correct path to the system Git config
  mingw: move Git for Windows' system config where users expect it
2021-07-16 17:42:46 -07:00
Junio C Hamano
508416d95c Merge branch 'ks/submodule-cleanup'
Code cleanup.

* ks/submodule-cleanup:
  submodule: remove unnecessary `prefix` based option logic
2021-07-16 17:42:46 -07:00
Junio C Hamano
3b57e72c0c Merge branch 'tb/midx-use-checksum'
When rebuilding the multi-pack index file reusing an existing one,
we used to blindly trust the existing file and ended up carrying
corrupted data into the updated file, which has been corrected.

* tb/midx-use-checksum:
  midx: report checksum mismatches during 'verify'
  midx: don't reuse corrupt MIDXs when writing
  commit-graph: rewrite to use checksum_valid()
  csum-file: introduce checksum_valid()
2021-07-16 17:42:46 -07:00
Junio C Hamano
d3b88be1b4 Merge branch 'en/merge-dir-rename-corner-case-fix'
The merge code had funny interactions between content based rename
detection and directory rename detection.

* en/merge-dir-rename-corner-case-fix:
  merge-recursive: handle rename-to-self case
  merge-ort: ensure we consult df_conflict and path_conflicts
  t6423: test directory renames causing rename-to-self
2021-07-16 17:42:45 -07:00
Junio C Hamano
fdbcdfcf61 Merge branch 'en/ort-perf-batch-13'
Performance tweaks of "git merge -sort" around lazy fetching of objects.

* en/ort-perf-batch-13:
  merge-ort: add prefetching for content merges
  diffcore-rename: use a different prefetch for basename comparisons
  diffcore-rename: allow different missing_object_cb functions
  t6421: add tests checking for excessive object downloads during merge
  promisor-remote: output trace2 statistics for number of objects fetched
2021-07-16 17:42:45 -07:00
Junio C Hamano
89efac81c7 Merge branch 'en/ort-perf-batch-12'
More fix-ups and optimization to "merge -sort".

* en/ort-perf-batch-12:
  merge-ort: miscellaneous touch-ups
  Fix various issues found in comments
  diffcore-rename: avoid unnecessary strdup'ing in break_idx
  merge-ort: replace string_list_df_name_compare with faster alternative
2021-07-16 17:42:45 -07:00
Junio C Hamano
5b1cd37e44 CodingGuidelines: recommend gender-neutral description
Technical writing seeks to convey information with minimal
friction. One way that a reader can experience friction is if they
encounter a description of "a user" that is later simplified using a
gendered pronoun. If the reader does not consider that pronoun to
apply to them, then they can experience cognitive dissonance that
removes focus from the information.

Give some basic tips to guide us avoid unnecessary uses of gendered
description.

Using a gendered pronoun is appropriate when referring to a specific
person.

There are acceptable existing uses of gendered pronouns within the
Git codebase, such as:

* References to real people (e.g. Linus Torvalds, "the Git maintainer").
  Do not misgender real people. If there is any doubt to the gender of a
  person, then avoid using pronouns.

* References to fictional people with clear genders (e.g. Alice and
  Bob).

* Sample text used in test cases (e.g t3702, t6432).

* The official text of the GPL license contains uses of "he or she",
  but using singular "they" (or modifying the text in some other
  way) is not within the scope of the Git project.

* Literal email messages in Documentation/howto/ should not be edited
  for grammatical concerns such as this, unless we update the entire
  document to fit the standard documentation format. If such an effort is
  taken on, then the authorship would change and no longer refer to the
  exact mail message.

* External projects consumed in contrib/ should not deviate solely for
  style reasons. Recommended edits should be contributed to those
  projects directly.

Other cases within the Git project were cleaned up by the previous
changes.

Co-authored-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-16 11:35:46 -07:00
Philippe Blain
ca2d62b787 parse-options: don't complete option aliases by default
Since 'OPT_ALIAS' was created in 5c387428f1 (parse-options: don't emit
"ambiguous option" for aliases, 2019-04-29), 'git clone
--git-completion-helper', which is used by the Bash completion script to
list options accepted by clone (via '__gitcomp_builtin'), lists both
'--recurse-submodules' and its alias '--recursive', which was not the
case before since '--recursive' had the PARSE_OPT_HIDDEN flag set, and
options with this flag are skipped by 'parse-options.c::show_gitcomp',
which implements 'git <cmd> --git-completion-helper'.

This means that typing 'git clone --recurs<TAB>' will yield both
'--recurse-submodules' and '--recursive', which is not ideal since both
do the same thing, and so the completion should directly complete the
canonical option.

At the point where 'show_gitcomp' is called in 'parse_options_step',
'preprocess_options' was already called in 'parse_options', so any
aliases are now copies of the original options with a modified help text
indicating they are aliases.

Helpfully, since 64cc539fd2 (parse-options: don't leak alias help
messages, 2021-03-21) these copies have the PARSE_OPT_FROM_ALIAS flag
set, so check that flag early in 'show_gitcomp' and do not print them,
unless the user explicitely requested that *all* completion be shown (by
setting 'GIT_COMPLETION_SHOW_ALL'). After all, if we want to encourage
the use of '--recurse-submodules' over '--recursive', we'd better just
suggest the former.

The only other options alias is 'log' and friends' '--mailmap', which is
an alias for '--use-mailmap', but the Bash completion helpers for these
commands do not use '__gitcomp_builtin', and thus are unnaffected by
this change.

Test the new behaviour in t9902-completion.sh. As a side effect, this
also tests the correct behaviour of GIT_COMPLETION_SHOW_ALL, which was
not tested before. Note that since '__gitcomp_builtin' caches the
options it shows, we need to re-source the completion script to clear
that cache for the second test.

Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-16 11:31:44 -07:00
Elijah Newren
94b82d5686 rename: bump limit defaults yet again
These were last bumped in commit 92c57e5c1d (bump rename limit
defaults (again), 2011-02-19), and were bumped both because processors
had gotten faster, and because people were getting ugly merges that
caused problems and reporting it to the mailing list (suggesting that
folks were willing to spend more time waiting).

Since that time:
  * Linus has continued recommending kernel folks to set
    diff.renameLimit=0 (maps to 32767, currently)
  * Folks with repositories with lots of renames were happy to set
    merge.renameLimit above 32767, once the code supported that, to
    get correct cherry-picks
  * Processors have gotten faster
  * It has been discovered that the timing methodology used last time
    probably used too large example files.

The last point is probably worth explaining a bit more:

  * The "average" file size used appears to have been average blob size
    in the linux kernel history at the time (probably v2.6.25 or
    something close to it).
  * Since bigger files are modified more frequently, such a computation
    weights towards larger files.
  * Larger files may be more likely to be modified over time, but are
    not more likely to be renamed -- the mean and median blob size
    within a tree are a bit higher than the mean and median of blob
    sizes in the history leading up to that version for the linux
    kernel.
  * The mean blob size in v2.6.25 was half the average blob size in
    history leading to that point
  * The median blob size in v2.6.25 was about 40% of the mean blob size
    in v2.6.25.
  * Since the mean blob size is more than double the median blob size,
    any file as big as the mean will not be compared to any files of
    median size or less (because they'd be more than 50% dissimilar).
  * Since it is the number of files compared that provides the O(n^2)
    behavior, median-sized files should matter more than mean-sized
    ones.

The combined effect of the above is that the file size used in past
calculations was likely about 5x too large.  Combine that with a CPU
performance improvement of ~30%, and we can increase the limits by
a factor of sqrt(5/(1-.3)) = 2.67, while keeping the original stated
time limits.

Keeping the same approximate time limit probably makes sense for
diff.renameLimit (there is no progress feedback in e.g. git log -p),
but the experience above suggests merge.renameLimit could be extended
significantly.  In fact, it probably would make sense to have an
unlimited default setting for merge.renameLimit, but that would
likely need to be coupled with changes to how progress is displayed.
(See https://lore.kernel.org/git/YOx+Ok%2FEYvLqRMzJ@coredump.intra.peff.net/
for details in that area.)  For now, let's just bump the approximate
time limit from 10s to 1m.

(Note: We do not want to use actual time limits, because getting results
that depend on how loaded your system is that day feels bad, and because
we don't discover that we won't get all the renames until after we've
put in a lot of work rather than just upfront telling the user there are
too many files involved.)

Using the original time limit of 2s for diff.renameLimit, and bumping
merge.renameLimit from 10s to 60s, I found the following timings using
the simple script at the end of this commit message (on an AWS c5.xlarge
which reports as "Intel(R) Xeon(R) Platinum 8124M CPU @ 3.00GHz"):

      N   Timing
   1300    1.995s
   7100   59.973s

So let's round down to nice even numbers and bump the limits from
400->1000, and from 1000->7000.

Here is the measure_rename_perf script (adapted from
https://lore.kernel.org/git/20080211113516.GB6344@coredump.intra.peff.net/
in particular to avoid triggering the linear handling from
basename-guided rename detection):

    #!/bin/bash

    n=$1; shift

    rm -rf repo
    mkdir repo && cd repo
    git init -q -b main

    mkdata() {
      mkdir $1
      for i in `seq 1 $2`; do
        (sed "s/^/$i /" <../sample
         echo tag: $1
        ) >$1/$i
      done
    }

    mkdata initial $n
    git add .
    git commit -q -m initial

    mkdata new $n
    git add .
    cd new
    for i in *; do git mv $i $i.renamed; done
    cd ..
    git rm -q -rf initial
    git commit -q -m new

    time git diff-tree -M -l0 --summary HEAD^ HEAD

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-15 16:54:34 -07:00
Elijah Newren
9dd29dbef0 diffcore-rename: treat a rename_limit of 0 as unlimited
In commit 89973554b5 (diffcore-rename: make diff-tree -l0 mean
-l<large>, 2017-11-29), -l0 was given a special magical "large" value,
but one which was not large enough for some uses (as can be seen from
commit 9f7e4bfa3b (diff: remove silent clamp of renameLimit,
2017-11-13).  Make 0 (or a negative value) be treated as unlimited
instead and update the documentation to mention this.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-15 16:54:24 -07:00
Elijah Newren
6623a528e0 doc: clarify documentation for rename/copy limits
A few places in the docs implied that rename/copy detection is always
quadratic or that all (unpaired) files were involved in the quadratic
portion of rename/copy detection.  The following two commits each
introduced an exception to this:

    9027f53cb5 (Do linear-time/space rename logic for exact renames,
                  2007-10-25)
    bd24aa2f97 (diffcore-rename: guide inexact rename detection based
                  on basenames, 2021-02-14)

(As a side note, for copy detection, the basename guided inexact rename
detection is turned off and the exact renames will only result in
sources (without the dests) being removed from the set of files used in
quadratic detection.  So, for copy detection, the documentation was
closer to correct.)

Avoid implying that all files involved in rename/copy detection are
subject to the full quadratic algorithm.  While at it, also note the
default values for all these settings.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-15 16:54:24 -07:00
Elijah Newren
05d2c61c67 diff: correct warning message when renameLimit exceeded
The warning when quadratic rename detection was skipped referred to
"inexact rename detection".  For years, the only linear portion of
rename detection was looking for exact renames, so "inexact rename
detection" was an accurate way to refer to the quadratic portion of
rename detection.  However, that changed with commit bd24aa2f97
(diffcore-rename: guide inexact rename detection based on basenames,
2021-02-14).  Let's instead use the term "exhaustive rename detection"
to refer to the quadratic portion.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-15 16:54:24 -07:00
Stephen Manz
0db4961c49 worktree: teach add to accept --reason <string> with --lock
The default reason stored in the lock file, "added with --lock",
is unlikely to be what the user would have given in a separate
`git worktree lock` command. Allowing `--reason` to be specified
along with `--lock` when adding a working tree gives the user control
over the reason for locking without needing a second command.

Signed-off-by: Stephen Manz <smanz@alum.mit.edu>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-15 13:30:59 -07:00
Johannes Schindelin
a066a90db6 ci(check-whitespace): restrict to the intended commits
During a run of the `check-whitespace` we want to verify that the
commits introduced in the Pull Request have no whitespace issues. We
only want to look at those commits, not the upstream commits (because
the contributor cannot do anything about the latter).

However, by using the `-<count>` form in `git log --check`, we run the
risk of looking at the wrong commits. The reason is that the
`actions/checkout` step does _not_ check out the tip commit of the Pull
Request's branch: Instead, it checks out a merge commit that merges that
branch into the target branch. For that reason, we already adjust the
commit count by incrementing it, but that is not enough: if the upstream
branch has newer commits, they are traversed _first_. And obviously we
will then miss some of the commits that we _actually_ wanted to look at.

Therefore, let's be careful to stop assuming a linear, up to date commit
topology in the contributed commits, and instead specify the correct
commit range.

Unfortunately, this means that we no longer can rely on a shallow clone:
There is no way of knowing just how many commits the upstream branch
advanced after the commit from which the PR branch branched off. So
let's just go with a full clone instead, and be safe rather than sorry
(if we have "too shallow" a situation, a commit range `@{u}..` may very
well include a shallow commit itself, and the output of `git show
--check <shallow>` is _not_ pretty).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 15:38:01 -07:00
Johannes Schindelin
cc00362125 ci(check-whitespace): stop requiring a read/write token
As part of some recent security tightening, GitHub introduced the
ability to configure GitHub workflows to be run with a read-only token.
This is much more secure, in particular when working in a public
repository: While the regular read/write token might be restricted to
writing to the current branch, it is not necessarily restricted to
access only the current Pull Request.

However, the `check-whitespace` workflow threw a wrench into this plan:
it _requires_ write access (because it wants to add a PR comment in case
of a whitespace issue).

Let's just skip that PR comment. The user can always click through to
the actual error, even if it is slightly less convenient.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 15:37:59 -07:00
Derrick Stolee
1ba5f45132 checkout: stop expanding sparse indexes
Previous changes did the necessary improvements to unpack-trees.c and
diff-lib.c in order to modify a sparse index based on its comparision
with a tree. The only remaining work is to remove some
ensure_full_index() calls and add tests that verify that the index is
not expanded in our interesting cases. Include 'switch' and 'restore' in
these tests, as they share a base implementation with 'checkout'.

Here are the relevant performance results from
p2000-sparse-operations.sh:

Test                                     HEAD~1           HEAD
--------------------------------------------------------------------------------
2000.18: git checkout -f - (full-v3)     0.49(0.43+0.03)  0.47(0.39+0.05) -4.1%
2000.19: git checkout -f - (full-v4)     0.45(0.37+0.06)  0.42(0.37+0.05) -6.7%
2000.20: git checkout -f - (sparse-v3)   0.76(0.71+0.07)  0.04(0.03+0.04) -94.7%
2000.21: git checkout -f - (sparse-v4)   0.75(0.72+0.04)  0.05(0.06+0.04) -93.3%

It is important to compare the full index case to the sparse index case,
as the previous results for the sparse index were inflated by the index
expansion. For index v4, this is an 88% improvement.

On an internal repository with over two million paths at HEAD and a
sparse-checkout definition containing ~60,000 of those paths, 'git
checkout' went from 3.5s to 297ms with this change. The theoretical
optimum where only those ~60,000 paths exist was 275ms, so the extra
sparse directory entries contribute a 22ms overhead.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 15:05:53 -07:00
Derrick Stolee
f934f1b47f sparse-index: recompute cache-tree
When some commands run with command_requires_full_index=1, then the
index can get in a state where the in-memory cache tree is actually
equal to the sparse index's cache tree instead of the full one.

This results in incorrect entry_count values. By clearing the cache
tree before converting to sparse, we avoid this issue.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 15:05:53 -07:00
Derrick Stolee
daa1acefc5 commit: integrate with sparse-index
Update 'git commit' to allow using the sparse-index in memory without
expanding to a full one. The only place that had an ensure_full_index()
call was in cache_tree_update(). The recursive algorithm for
update_one() was already updated in 2de37c536 (cache-tree: integrate
with sparse directory entries, 2021-03-03) to handle sparse directory
entries in the index.

Most of this change involves testing different command-line options that
allow specifying which on-disk changes should be included in the commit.
This includes no options (only take currently-staged changes), -a (take
all tracked changes), and --include (take a list of specific changes).
To simplify testing that these options do not expand the index, update
the test that previously verified that 'git status' does not expand the
index with a helper method, ensure_not_expanded().

This allows 'git commit' to operate much faster when the sparse-checkout
cone is much smaller than the full list of files at HEAD.

Here are the relevant lines from p2000-sparse-operations.sh:

Test                                      HEAD~1           HEAD
----------------------------------------------------------------------------------
2000.14: git commit -a -m A (full-v3)     0.35(0.26+0.06)  0.36(0.28+0.07) +2.9%
2000.15: git commit -a -m A (full-v4)     0.32(0.26+0.05)  0.34(0.28+0.06) +6.3%
2000.16: git commit -a -m A (sparse-v3)   0.63(0.59+0.06)  0.04(0.05+0.05) -93.7%
2000.17: git commit -a -m A (sparse-v4)   0.64(0.59+0.08)  0.04(0.04+0.04) -93.8%

It is important to compare the full-index case to the sparse-index case,
so the improvement for index version v4 is actually an 88% improvement in
this synthetic example.

In a real repository with over two million files at HEAD and 60,000
files in the sparse-checkout definition, the time for 'git commit -a'
went from 2.61 seconds to 134ms. I compared this to the result if the
index only contained the paths in the sparse-checkout definition and
found the theoretical optimum to be 120ms, so the out-of-cone paths only
add a 12% overhead.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 15:05:53 -07:00
Derrick Stolee
11042ab914 p2000: compress repo names
By using shorter names for the test repos, we will get a slightly more
compressed performance summary without comprimising clarity.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 15:05:53 -07:00
Derrick Stolee
0d53d19946 p2000: add 'git checkout -' test and decrease depth
As we increase our list of commands to test in
p2000-sparse-operations.sh, we will want to have a slightly smaller test
repository. Reduce the size by a factor of four by reducing the depth of
the step that creates a big index around a moderately-sized repository.

Also add a step to run 'git checkout -' on repeat. This requires having
a previous location in the reflog, so add that to the initialization
steps.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 15:05:53 -07:00
Derrick Stolee
e5ca291076 t1092: document bad sparse-checkout behavior
There are several situations where a repository with sparse-checkout
enabled will act differently than a normal repository, and in ways that
are not intentional. The test t1092-sparse-checkout-compatibility.sh
documents some of these deviations, but a casual reader might think
these are intentional behavior changes.

Add comments on these tests that make it clear that these behaviors
should be updated. Using 'NEEDSWORK' helps contributors find that these
are potential areas for improvement.

Helped-by: Elijah Newren <newren@gmail.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 13:42:49 -07:00
Derrick Stolee
f8fe49e539 fsmonitor: integrate with sparse index
If we need to expand a sparse-index into a full one, then the FS Monitor
bitmap is going to be incorrect. Ensure that we start fresh at such an
event.

While this is currently a performance drawback, the eventual hope of the
sparse-index feature is that these expansions will be rare and hence we
will be able to keep the FS Monitor data accurate across multiple Git
commands.

These tests are added to demonstrate that the behavior is the same
across a full index and a sparse index, but also that file modifications
to a tracked directory outside of the sparse cone will trigger
ensure_full_index().

Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 13:42:49 -07:00
Derrick Stolee
fe0d576153 wt-status: expand added sparse directory entries
It is difficult, but possible, to get into a state where we intend to
add a directory that is outside of the sparse-checkout definition. Add a
test to t1092-sparse-checkout-compatibility.sh that demonstrates this
using a combination of 'git reset --mixed' and 'git checkout --orphan'.

This test failed before because the output of 'git status
--porcelain=v2' would not match on the lines for folder1/:

* The sparse-checkout repo (with a full index) would output each path
  name that is intended to be added.

* The sparse-index repo would only output that "folder1/" is staged for
  addition.

The status should report the full list of files to be added, and so this
sparse-directory entry should be expanded to a full list when reaching
it inside the wt_status_collect_changes_initial() method. Use
read_tree_at() to assist.

Somehow, this loop over the cache entries was not guarded by
ensure_full_index() as intended.

Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 13:42:49 -07:00
Derrick Stolee
d76723ee53 status: use sparse-index throughout
By testing 'git -c core.fsmonitor= status -uno', we can check for the
simplest index operations that can be made sparse-aware. The necessary
implementation details are already integrated with sparse-checkout, so
modify command_requires_full_index to be zero for cmd_status().

In refresh_index(), we loop through the index entries to refresh their
stat() information. However, sparse directories have no stat()
information to populate. Ignore these entries.

This allows 'git status' to no longer expand a sparse index to a full
one. This is further tested by dropping the "-uno" option and adding an
untracked file into the worktree.

The performance test p2000-sparse-checkout-operations.sh demonstrates
these improvements:

Test                                  HEAD~1           HEAD
-----------------------------------------------------------------------------
2000.2: git status (full-index-v3)    0.31(0.30+0.05)  0.31(0.29+0.06) +0.0%
2000.3: git status (full-index-v4)    0.31(0.29+0.07)  0.34(0.30+0.08) +9.7%
2000.4: git status (sparse-index-v3)  2.35(2.28+0.10)  0.04(0.04+0.05) -98.3%
2000.5: git status (sparse-index-v4)  2.35(2.24+0.15)  0.05(0.04+0.06) -97.9%

Note that since HEAD~1 was expanding the sparse index by parsing trees,
it was artificially slower than the full index case. Thus, the 98%
improvement is misleading, and instead we should celebrate the 0.34s to
0.05s improvement of 85%. This is more indicative of the peformance
gains we are expecting by using a sparse index.

Note: we are dropping the assignment of core.fsmonitor here. This is not
necessary for the test script as we are not altering the config any
other way. Correct integration with FS Monitor will be validated in
later changes.

Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 13:42:49 -07:00
Derrick Stolee
bf48e5acdb status: skip sparse-checkout percentage with sparse-index
'git status' began reporting a percentage of populated paths when
sparse-checkout is enabled in 051df3cf (wt-status: show sparse
checkout status as well, 2020-07-18). This percentage is incorrect when
the index has sparse directories. It would also be expensive to
calculate as we would need to parse trees to count the total number of
possible paths.

Avoid the expensive computation by simplifying the output to only report
that a sparse checkout exists, without the percentage.

This change is the reason we use 'git status --porcelain=v2' in
t1092-sparse-checkout-compatibility.sh. We don't want to ensure that
this message is equal across both modes, but instead just the important
information about staged, modified, and untracked files are compared.

Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 13:42:49 -07:00
Derrick Stolee
9eb00af562 diff-lib: handle index diffs with sparse dirs
While comparing an index to a tree, we may see a sparse directory entry.
In this case, we should compare that portion of the tree to the tree
represented by that entry. This could include a new tree which needs to
be expanded to a full list of added files. It could also include an
existing tree, in which case all of the changes inside are important to
describe, including the modifications, additions, and deletions. Note
that the case where the tree has a path and the index does not remains
identical to before: the lack of a cache entry is the same with a sparse
index.

Use diff_tree_oid() appropriately to compute the diff.

Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 13:42:49 -07:00
Derrick Stolee
69bdbdb0ee dir.c: accept a directory as part of cone-mode patterns
When we have sparse directory entries in the index, we want to compare
that directory against sparse-checkout patterns. Those pattern matching
algorithms are built expecting a file path, not a directory path. This
is especially important in the "cone mode" patterns which will match
files that exist within the "parent directories" as well as the
recursive directory matches.

If path_matches_pattern_list() is given a directory, we can add a fake
filename ("-") to the directory and get the same results as before,
assuming we are in cone mode. Since sparse index requires cone mode
patterns, this is an acceptable assumption.

Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 13:42:49 -07:00
Derrick Stolee
523506df51 unpack-trees: unpack sparse directory entries
During unpack_callback(), index entries are compared against tree
entries. These are matched according to names and types. One goal is to
decide if we should recurse into subtrees or simply operate on one index
entry.

In the case of a sparse-directory entry, we do not want to recurse into
that subtree and instead simply compare the trees. In some cases, we
might want to perform a merge operation on the entry, such as during
'git checkout <commit>' which wants to replace a sparse tree entry with
the tree for that path at the target commit. We extend the logic within
unpack_single_entry() to create a sparse-directory entry in this case,
and then that is sent to call_unpack_fn().

There are some subtleties in this process. For instance, we need to
update find_cache_entry() to allow finding a sparse-directory entry that
exactly matches a given path. Use the new helper method
sparse_dir_matches_path() for this. We also need to ignore conflict
markers in the case that the entries correspond to directories and we
already have a sparse directory entry.

Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 13:42:49 -07:00