From Documentation/revisions.txt:
'<describeOutput>', e.g. 'v1.7.4.2-679-g3bee7fb'::
Output from `git describe`; i.e. a closest tag, optionally
followed by a dash and a number of commits, followed by a dash, a
'g', and an abbreviated object name.
which means that output of the format
${REFNAME}-${INTEGER}-g${HASH}
should parse to fully expanded ${HASH}. This is fine. However, we
currently don't validate any of ${REFNAME}-${INTEGER}, we only parse
-g${HASH} and assume the rest is valid. That is problematic, since it
breaks things like
git cat-file -p branchname:path/to/file/named/i-gaffed
which, when commit (or tree or blob) affed exists, will not return us
information about the file we are looking for but will instead
erroneously tell us about object affed.
A few additional notes:
- This is a slight backward incompatibility break, because we used
to allow ${GARBAGE}-g${HASH} as a way to spell ${HASH}. However,
a backward incompatible break is necessary, because there is no
other way for someone to be more specific and disambiguate that they
want the blob master:path/to/who-gabbed instead of the object abbed.
- There is a possibility that check_refname_format() rules change in
the future. However, we can only realistically loosen the rules
for what that function accepts rather than tighten. If we were to
tighten the rules, some real world repositories may already have
refnames that suddenly become unacceptable and we break those
repositories. As such, any describe-like syntax of the form
${VALID_FOR_A_REFNAME}-${INTEGER}-g${HASH} that is valid with the
changes in this commit will remain valid in the future.
- The fact that check_refname_format() rules could loosen in the
future is probably also an important reason to make this change. If
the rules loosen, there might be additional cases within
${GARBAGE}-g${HASH} that become ambiguous in the future. While
abbreviated hashes can be disambiguated by abbreviating less, it may
well be that these alternative object names have no way of being
disambiguated (much like pathnames cannot be). Accepting all random
${GARBAGE} thus makes it difficult for us to allow future
extensions to object naming.
So, tighten up the parsing to make sure ${REFNAME} and ${INTEGER} are
present in the string, and would be considered a valid ref and
non-negative integer.
Also, add a few tests for git describe using object names of the form
${REVISION_NAME}${MODIFIERS}
since an early version of this patch failed on constructs like
git describe v2.48.0-rc2-161-g6c2274cdbc^0
Reported-by: Gabriel Amaral <gabriel-amaral@github.com>
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git describe" optimization.
* jk/describe-perf:
describe: split "found all tags" and max_candidates logic
describe: stop traversing when we run out of names
describe: stop digging for max_candidates+1
t/perf: add tests for git-describe
t6120: demonstrate weakness in disjoint-root handling
Commit a30154187a (describe: stop traversing when we run out of names,
2024-10-31) taught git-describe to automatically reduce the
max_candidates setting to match the total number of possible names. This
lets us break out of the traversal rather than fruitlessly searching for
more candidates when there are no more to be found.
However, setting max_candidates to 0 (e.g., if the repo has no tags)
overlaps with the --exact-match option, which explicitly uses the same
value. And this causes a regression with --always, which is ignored in
exact-match mode. We used to get this in a repo with no tags:
$ git describe --always HEAD
b2f0a7f
and now we get:
$ git describe --always HEAD
fatal: no tag exactly matches 'b2f0a7f47f5f2aebe1e7fceff19a57de20a78c06'
The reason is that we bail early in describe_commit() when
max_candidates is set to 0. This logic goes all the way back to
2c33f75754 (Teach git-describe --exact-match to avoid expensive tag
searches, 2008-02-24).
We should obviously fix this regression, but there are two paths,
depending on what you think:
$ git describe --always --exact-match
and
$ git describe --always --candidates=0
should do. Since the "--always" option was added, it has always been
ignored in --exact-match (or --candidates=0) mode. I.e., we treat
--exact-match as a true exact match of a tag, and never fall back to
using --always, even if it was requested.
If we think that's a bug (or at least a misfeature), then the right
solution is to fix it by removing the early bail-out from 2c33f75754,
letting the noop algorithm run and then hitting the --always fallback
output. And then our regression naturally goes away, because it follows
the same path.
If we think that the current "--exact-match --always" behavior is the
right thing, then we have to differentiate the case where we
automatically reduced max_candidates to 0 from the case where the user
asked for it specifically. That's possible to do with a flag, but we can
also just reimplement the logic from a30154187a to explicitly break out
of the traversal when we run out of candidates (rather than relying on
the existing max_candidates check).
My gut feeling is along the lines of option 1 (it's a bug, and people
would be happy for "--exact-match --always" to give the fallback rather
than ignoring "--always"). But the documentation can be interpreted in
the other direction, and we've certainly lived with the existing
behavior for many years. So it's possible that changing it now is the
wrong thing.
So this patch fixes the regression by taking the second option,
retaining the "--exact-match" behavior as-is. There are two new tests.
The first shows that the regression is fixed (we don't even need a new
repo without tags; a restrictive --match is enough to create the
situation that there are no candidate names).
The second test confirms that the "--exact-match --always" behavior
remains unchanged and continues to die when there is no tag pointing at
the specified commit. It's possible we may reconsider this in the
future, but this shows that the approach described above is implemented
faithfully.
We can also run the perf tests in p6100 to see that we've retained the
speedup that a30154187a was going for:
Test HEAD^ HEAD
--------------------------------------------------------------------------------------
6100.2: describe HEAD 0.72(0.64+0.07) 0.72(0.66+0.06) +0.0%
6100.3: describe HEAD with one max candidate 0.01(0.00+0.00) 0.01(0.00+0.00) +0.0%
6100.4: describe HEAD with one tag 0.01(0.01+0.00) 0.01(0.01+0.00) +0.0%
Reported-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that the default value for TEST_PASSES_SANITIZE_LEAK is `true` there
is no longer a need to have that variable declared in all of our tests.
Drop it.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 30b1c7ad9d (describe: don't abort too early when searching tags,
2020-02-26) tried to fix a problem that happens when there are disjoint
histories: to accurately compare the counts for different tags, we need
to keep walking the history longer in order to find a common base.
But its fix misses a case: we may still bail early if we hit the
max_candidates limit, producing suboptimal output. You can see this in
action by adding "--candidates=2" to the tests; we'll stop traversing as
soon as we see the second tag and will produce the wrong answer. I hit
this in practice while trying to teach git-describe not to keep looking
for candidates after we've seen all tags in the repo (effectively adding
--candidates=2, since these toy repos have only two tags each).
This is probably fixable by continuing to walk after hitting the
max-candidates limit, all the way down to a common ancestor of all
candidates. But it's not clear in practice what the preformance
implications would be (it would depend on how long the branches that
hold the candidates are).
So I'm punting on that for now, but I'd like to adjust the tests to be
more resilient, and to document the findings. So this patch:
1. Adds an extra tag at the bottom of history. This shouldn't change
the output, but does mean we are more resilient to low values of
--candidates (e.g., if we start reducing it to the total number of
tags). This is arguably closer to the real world anyway, where
you're not going to have just 2 tags, but an arbitrarily long
history going back in time, possibly with multiple irrelevant tags
in it (I called the new tag "H" here for "history").
2. Run the same tests with --candidates=2, which shows that even with
the current code they can fail if we end the traversal early. That
leaves a trail for anybody interested in trying to improve the
behavior.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are several structures that we don't release after
`cmd_name_rev()` is done. Plug those leaks.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When describe is run with 'dirty' flag, we refresh the index
to make sure it is in sync with the filesystem before
determining if the working tree is dirty. However, this is
not done for the codepath where the 'broken' flag is used.
This causes `git describe --broken --dirty` to false
positively report the worktree being dirty if a file has
different stat info than what is recorded in the index.
Running `git update-index -q --refresh` to refresh the index
before running diff-index fixes the problem.
Also add tests to deliberately update stat info of a
file before running describe to verify it behaves correctly.
Reported-by: Paul Millar <paul.millar@desy.de>
Suggested-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Phillip Wood <phillip.wood123@gmail.com>
Signed-off-by: Abhijeet Sonar <abhijeet.nkt@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
They are equivalents and the former still exists, so as long as the
only change this commit makes are to rewrite test_i18ngrep to
test_grep, there won't be any new bug, even if there still are
callers of test_i18ngrep remaining in the tree, or when merged to
other topics that add new uses of test_i18ngrep.
This patch was produced more or less with
git grep -l -e 'test_i18ngrep ' 't/t[0-9][0-9][0-9][0-9]-*.sh' |
xargs perl -p -i -e 's/test_i18ngrep /test_grep /'
and a good way to sanity check the result yourself is to run the
above in a checkout of c4603c1c (test framework: further deprecate
test_i18ngrep, 2023-10-31) and compare the resulting working tree
contents with the result of applying this patch to the same commit.
You'll see that test_i18ngrep in a few t/lib-*.sh files corrected,
in addition to the manual reproduction.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Since 2c33f75754 (Teach git-describe --exact-match to avoid expensive
tag searches, 2008-02-24) git describe accepts --no-exact-match, but it
does the same as --exact-match, an alias for --candidates=0. That's
because it's defined using OPT_SET_INT with a value of 0, which sets 0
when negated as well.
Let --no-exact-match set the number of candidates to the default value
instead. Users that need a more specific lack of exactitude can specify
their preferred value using --candidates, as before.
The "--no-exact-match" option was not covered in the tests, so let's
add a few. Also add a case where --exact-match option is used on a
commit that cannot be described without distance from tags and make
sure the command fails.
Signed-off-by: René Scharfe <l.s.r@web.de>
[jc: added trivial tests]
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 7550424804 ("name-rev: include taggerdate in considering the best
name", 2016-04-22) introduced the idea of using taggerdate in the
criteria for selecting the best name. At the time, a certain commit in
linux.git -- namely, aed06b9cfcab -- was being named by name-rev as
v4.6-rc1~9^2~792
which, while correct, was very suboptimal. Some investigation found
that tweaking the MERGE_TRAVERSAL_WEIGHT to lower it could give
alternate answers such as
v3.13-rc7~9^2~14^2~42
or
v3.13~5^2~4^2~2^2~1^2~42
A manual solution involving looking at tagger dates came up with
v3.13-rc1~65^2^2~42
which is much nicer. That workaround was then implemented in name-rev.
Unfortunately, the taggerdate heuristic is causing bugs. I was pointed
to a case in a private repository where name-rev reports a name of the
form
v2022.10.02~86
when users expected to see one of the form
v2022.10.01~2
(I've modified the names and numbers a bit from the real testcase.) As
you can probably guess, v2022.10.01 was created after v2022.10.02 (by a
few hours), even though it pointed to an older commit. While the
condition is unusual even in the repository in question, it is not the
only problematic set of tags in that repository. The taggerdate logic
is causing problems.
Further, it turns out that this taggerdate heuristic isn't even helping
anymore. Due to the fix to naming logic in 3656f84278 ("name-rev:
prefer shorter names over following merges", 2021-12-04), we get
improved names without the taggerdate heuristic. For the original
commit of interest in linux.git, a modern git without the taggerdate
heuristic still provides the same optimal answer of interest, namely:
v3.13-rc1~65^2^2~42
So, the taggerdate is no longer providing benefit, and it is causing
problems. Simply get rid of it.
However, note that "taggerdate" as a variable is used to store things
besides a taggerdate these days. Ever since commit ef1e74065c
("name-rev: favor describing with tags and use committer date to
tiebreak", 2017-03-29), this has been used to store committer dates and
there it is used as a fallback tiebreaker (as opposed to a primary
criteria overriding effective distance calculations). We do not want to
remove that fallback tiebreaker, so not all instances of "taggerdate"
are removed in this change.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If a commit in a sequence of linear history has a non-monotonically
increasing commit timestamp, git name-rev might not properly name the
commit.
This occurs because name-rev uses a heuristic of the commit date to
avoid searching down tags which lead to commits that are older than the
named commit. This is intended to avoid work on larger repositories.
This heuristic impacts git name-rev, and by extension git describe
--contains which is built on top of name-rev.
Further more, if --all or --annotate-stdin is used, the heuristic is not
enabled because the full history has to be analyzed anyways. This
results in some confusion if a user sees that --annotate-stdin works but
a normal name-rev does not.
If the repository has a commit graph, we can use the generation numbers
instead of using the commit dates. This is essentially the same check
except that generation numbers make it exact, where the commit date
heuristic could be incorrect due to clock errors.
Since we're extending the notion of cutoff to more than one variable,
create a series of functions for setting and checking the cutoff. This
avoids duplication and moves access of the global cutoff and
generation_cutoff to as few functions as possible.
Add several test cases including a test that covers the new commitGraph
behavior, as well as tests for --all and --annotate-stdin with and
without commitGraphs.
Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git name-rev --stdin" does not behave like usual "--stdin" at
all. Start the process of renaming it to "--annotate-stdin".
* jc/name-rev-stdin:
name-rev.c: use strbuf_getline instead of limited size buffer
name-rev: deprecate --stdin in favor of --annotate-stdin
Introduce a --annotate-stdin that is functionally equivalent of --stdin.
--stdin does not behave as --stdin in other subcommands, such as
pack-objects whereby it takes one argument per line. Since --stdin can
be a confusing and misleading name, rename it to --annotate-stdin.
This change adds a warning to --stdin warning that it will be removed in
the future.
Signed-off-by: "John Cai" <johncai86@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Failures within `for` and `while` loops can go unnoticed if not detected
and signaled manually since the loop itself does not abort when a
contained command fails, nor will a failure necessarily be detected when
the loop finishes since the loop returns the exit code of the last
command it ran on the final iteration, which may not be the command
which failed. Therefore, detect and signal failures manually within
loops using the idiom `|| return 1` (or `|| exit 1` within subshells).
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The top-level &&-chain checker built into t/test-lib.sh causes tests to
magically exit with code 117 if the &&-chain is broken. However, it has
the shortcoming that the magic does not work within `{...}` groups,
`(...)` subshells, `$(...)` substitutions, or within bodies of compound
statements, such as `if`, `for`, `while`, `case`, etc. `chainlint.sed`
partly fills in the gap by catching broken &&-chains in `(...)`
subshells, but bugs can still lurk behind broken &&-chains in the other
cases.
Fix broken &&-chains in compound statements in order to reduce the
number of possible lurking bugs.
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change a subshell added in a preceding commit to instead use a new
"-C" option to "check_describe". The idiom for this is copied as-is
from the "test_commit" function in test-lib-functions.sh
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix a nested invocation of "test_expect_success", the
"check_describe()" function is a wrapper for calling
test_expect_success, and therefore needs to be called outside the body
of another "test_expect_success".
The two tests added in 30b1c7ad9d (describe: don't abort too early
when searching tags, 2020-02-26) were not testing for anything due to
this logic error. Without this fix reverting the C code changes in
that commit still has all tests passing, with this fix we're actually
testing the "describe" output. This is because "test_expect_success"
calls "test_finish_", whose last statement happens to be true.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the one test that relied on the "err.actual" file produced by
check_describe() to instead do its own check of "git describe"
output.
This means that the two tests won't have an inter-dependency (e.g. if
the earlier test is skipped).
An earlier version of this patch instead asserted that no other test
had any output on stderr. We're not doing that here out of fear that
"gc --auto" or another future change to "git describe" will cause it
to legitimately emit output on stderr unexpectedly[1].
I'd think that inverting the test added in 3291fe4072 (Add
git-describe test for "verify annotated tag names on output",
2008-03-03) to make checking that we don't have warnings the rule
rather than the exception would be the sort of thing the describe
tests should be catching, but for now let's leave it as it is.
1. http://lore.kernel.org/git/xmqqwnuqo8ze.fsf@gitster.c.googlers.com
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Change the glob matching via a "case" statement to a "test_cmp" after
we've stripped out the hash-specific g<hash-abbrev>
suffix. 5312ab11fb (Add describe test., 2007-01-13).
This means that we can use test_cmp to compare the output. I could
omit the "-8" change of e.g. "A-*" to "A-8-gHASH", but I think it
makes sense to test that here explicitly. It means you need to add new
tests to the bottom of the file, but that's not a burden in this case.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Improve tests added in 9f67d2e827 (Teach "git describe" --dirty
option, 2009-10-21) and 2ed5c8e174 (describe: setup working tree for
--dirty, 2019-02-03) so that they make sense in combination with each
other.
The "check_describe" being removed here was the earlier test, we then
later added these --work-tree tests which really just wanted to check
if we got the exact same output from "describe", but the test wasn't
structured to test for that.
Let's change it to do that, which both improves test coverage and
makes it more obvious what's going on here.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert the setup of the describe tests to use test_commit when
possible. This makes use of the new --annotate option to test_commit.
Some of the setup here could simply be removed since the data being
created wasn't important to any of the subsequent tests, so I've done
so. E.g. assigning to the "one" variable was always useless, and just
checking that we can describe HEAD after the first commit wasn't
useful.
In the case of the "two" variable we could instead use the tag we just
created. See 5312ab11fb (Add describe test., 2007-01-13) for the
initial version of this code. There's other cases here like redundant
"test_tick" invocations, or the simplification of not echoing "X" to a
file we're about to tag as "x", now we just use "x" in both cases.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As a follow-up to d162b25f95 (tests: remove support for
GIT_TEST_GETTEXT_POISON, 2021-01-20) remove most uses of test_i18ncmp
via a simple s/test_i18ncmp/test_cmp/g search-replacement.
I'm leaving t6300-for-each-ref.sh out due to a conflict with in-flight
changes between "master" and "seen", as well as the prerequisite
itself due to other changes between "master" and "next/seen" which add
new test_i18ncmp uses.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Carefully excluding t6300, which sees independent development elsewhere
at the time of writing, we use `main` as the default branch name in
t6[0-3]*. This trick was performed via
$ (cd t &&
sed -i -e 's/master/main/g' -e 's/MASTER/MAIN/g' \
-e 's/Master/Main/g' -- t6[0-3]*.sh &&
git checkout HEAD -- t6300\*)
This allows us to define `GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main`
for those tests.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In addition to the manual adjustment to let the `linux-gcc` CI job run
the test suite with `master` and then with `main`, this patch makes sure
that GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME is set in all test scripts
that currently rely on the initial branch name being `master by default.
To determine which test scripts to mark up, the first step was to
force-set the default branch name to `master` in
- all test scripts that contain the keyword `master`,
- t4211, which expects `t/t4211/history.export` with a hard-coded ref to
initialize the default branch,
- t5560 because it sources `t/t556x_common` which uses `master`,
- t8002 and t8012 because both source `t/annotate-tests.sh` which also
uses `master`)
This trick was performed by this command:
$ sed -i '/^ *\. \.\/\(test-lib\|lib-\(bash\|cvs\|git-svn\)\|gitweb-lib\)\.sh$/i\
GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=master\
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME\
' $(git grep -l master t/t[0-9]*.sh) \
t/t4211*.sh t/t5560*.sh t/t8002*.sh t/t8012*.sh
After that, careful, manual inspection revealed that some of the test
scripts containing the needle `master` do not actually rely on a
specific default branch name: either they mention `master` only in a
comment, or they initialize that branch specificially, or they do not
actually refer to the current default branch. Therefore, the
aforementioned modification was undone in those test scripts thusly:
$ git checkout HEAD -- \
t/t0027-auto-crlf.sh t/t0060-path-utils.sh \
t/t1011-read-tree-sparse-checkout.sh \
t/t1305-config-include.sh t/t1309-early-config.sh \
t/t1402-check-ref-format.sh t/t1450-fsck.sh \
t/t2024-checkout-dwim.sh \
t/t2106-update-index-assume-unchanged.sh \
t/t3040-subprojects-basic.sh t/t3301-notes.sh \
t/t3308-notes-merge.sh t/t3423-rebase-reword.sh \
t/t3436-rebase-more-options.sh \
t/t4015-diff-whitespace.sh t/t4257-am-interactive.sh \
t/t5323-pack-redundant.sh t/t5401-update-hooks.sh \
t/t5511-refspec.sh t/t5526-fetch-submodules.sh \
t/t5529-push-errors.sh t/t5530-upload-pack-error.sh \
t/t5548-push-porcelain.sh \
t/t5552-skipping-fetch-negotiator.sh \
t/t5572-pull-submodule.sh t/t5608-clone-2gb.sh \
t/t5614-clone-submodules-shallow.sh \
t/t7508-status.sh t/t7606-merge-custom.sh \
t/t9302-fast-import-unpack-limit.sh
We excluded one set of test scripts in these commands, though: the range
of `git p4` tests. The reason? `git p4` stores the (foreign) remote
branch in the branch called `p4/master`, which is obviously not the
default branch. Manual analysis revealed that only five of these tests
actually require a specific default branch name to pass; They were
modified thusly:
$ sed -i '/^ *\. \.\/lib-git-p4\.sh$/i\
GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=master\
export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME\
' t/t980[0167]*.sh t/t9811*.sh
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When "git describe C" finds an annotated tag with tagname A to be
the best name to explain commit C, and the tag is stored in a
"wrong" place in the refs/tags hierarchy, e.g. refs/tags/B, the
command gave a warning message but used A (not B) to describe C.
If C is exactly at the tag, the describe output would be "A", but
"git rev-parse A^0" would not be equal as "git rev-parse C^0". The
behavior of the command has been changed to use the "long" form
i.e. A-0-gOBJECTNAME, which is correctly interpreted by rev-parse.
* jc/describe-misnamed-annotated-tag:
describe: force long format for a name based on a mislocated tag
When searching the commit graph for tag candidates, `git-describe`
will stop as soon as there is only one active branch left and
it already found an annotated tag as a candidate.
This works well as long as all branches eventually connect back
to a common root, but if the tags are found across branches
with no common ancestor
B
o----.
\
o-----o---o----x
A
it can happen that the search on one branch terminates prematurely
because a tag was found on another, independent branch. This scenario
isn't quite as obscure as it sounds, since cloning with a limited
depth often introduces many independent "dead ends" into the commit
graph.
The help text of `git-describe` states pretty clearly that when
describing a commit D, the number appended to the emitted tag X should
correspond to the number of commits found by `git log X..D`.
Thus, this commit modifies the stopping condition to only abort
the search when only one branch is left to search *and* all current
best candidates are descendants from that branch.
For repositories with a single root, this condition is always
true: When the search is reduced to a single active branch, the
current commit must be an ancestor of *all* tag candidates. This
means that in the common case, this change will have no negative
performance impact since the same number of commits as before will
be traversed.
Signed-off-by: Benno Evers <benno@bmevers.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An annotated tag has two names: where it sits in the refs/tags
hierarchy and the tagname recorded in the "tag" field in the object
itself. They usually should match.
Since 212945d4 ("Teach git-describe to verify annotated tag names
before output", 2008-02-28), a commit described using an annotated
tag bases its name on the tagname from the object. While this was a
deliberate design decision to make it easier to converse about tags
with others, even if the tags happen to be fetched to a different
name than it was given by its creator, it had one downside.
The output from "git describe", at least in the modern Git, should
be usable as an object name to name the exact commit given to the
"git describe" command. Using the tagname, when two names differ,
breaks this property, when describing a commit that is directly
pointed at by such a tag. An annotated tag Bob made as "v1.0" may
sit at "refs/tags/v1.0-bob" in the ref hierarchy, and output from
"git describe v1.0-bob^0" would say "v1.0", but there may not be
any tag at "refs/tags/v1.0" locally or there may be another tag that
points at a different object.
Note that this won't be a problem if a commit being described is not
directly pointed at by such a mislocated tag. In the example in the
previous paragraph, describing a commit whose parent is v1.0-bob
would result in "v1.0" (i.e. the tagname taken from the tag object)
followed by "-1-gXXXXX" where XXXXX is the abbreviated object name,
and a string that ends with "-g" followed by a hexadecimal string is
an object name for the object whose name begins with hexadecimal
string (as long as it is unique), so it does not matter if the
leading part is "v1.0" or "v1.0-bob".
Show the name in the long format, i.e. with "-0-gXXXXX" suffix, when
the name we give is based on a mislocated annotated tag to ensure
that the output can be used as the object name for the object
originally given to the command to fix the issue.
While at it, remove an overly cautious dead code to protect against
an annotated tag object without the tagname. Such a tag is filtered
out much earlier in the codeflow, and will not reach this part of
the code.
Helped-by: Matheus Tavares <matheus.bernardino@usp.br>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The name_rev() function calls itself recursively for each interesting
parent of the commit it got as parameter, and, consequently, it can
segfault when processing a deep history if it exhausts the available
stack space. E.g. running 'git name-rev --all' and 'git name-rev
HEAD~100000' in the gcc, gecko-dev, llvm, and WebKit repositories
results in segfaults on my machine ('ulimit -s' reports 8192kB of
stack size limit), and nowadays the former segfaults in the Linux repo
as well (it reached the necessasry depth sometime between v5.3-rc4 and
-rc5).
Eliminate the recursion by inserting the interesting parents into a
LIFO 'prio_queue' [1] and iterating until the queue becomes empty.
Note that the parent commits must be added in reverse order to the
LIFO 'prio_queue', so their relative order is preserved during
processing, i.e. the first parent should come out first from the
queue, because otherwise performance greatly suffers on mergy
histories [2].
The stacksize-limited test 'name-rev works in a deep repo' in
't6120-describe.sh' demonstrated this issue and expected failure. Now
the recursion is gone, so flip it to expect success. Also gone are
the dmesg entries logging the segfault of that segfaulting 'git
name-rev' process on every execution of the test suite.
Note that this slightly changes the order of lines in the output of
'git name-rev --all', usually swapping two lines every 35 lines in
git.git or every 150 lines in linux.git. This shouldn't matter in
practice, because the output has always been unordered anyway.
This patch is best viewed with '--ignore-all-space'.
[1] Early versions of this patch used a 'commit_list', resulting in
~15% performance penalty for 'git name-rev --all' in 'linux.git',
presumably because of the memory allocation and release for each
insertion and removal. Using a LIFO 'prio_queue' has basically no
effect on performance.
[2] We prefer shorter names, i.e. 'v0.1~234' is preferred over
'v0.1^2~5', meaning that usually following the first parent of a
merge results in the best name for its ancestors. So when later
we follow the remaining parent(s) of a merge, and reach an already
named commit, then we usually find that we can't give that commit
a better name, and thus we don't have to visit any of its
ancestors again.
OTOH, if we were to follow the Nth parent of the merge first, then
the name of all its ancestors would include a corresponding '^N'.
Those are not the best names for those commits, so when later we
reach an already named commit following the first parent of that
merge, then we would have to update the name of that commit and
the names of all of its ancestors as well. Consequently, we would
have to visit many commits several times, resulting in a
significant slowdown.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In 'builtin/name-rev.c' in the name_rev() function there is a loop
iterating over all parents of the given commit, and the loop body
looks like this:
if (parent_number > 1) {
if (generation > 0)
// branch #1
new_name = ...
else
// branch #2
new_name = ...
name_rev(parent, new_name, ...);
} else {
// branch #3
name_rev(...);
}
These conditions are not covered properly in the test suite. As far
as purely test coverage goes, they are all executed several times over
in 't6120-describe.sh'. However, they don't directly influence the
command's output, because the repository used in that test script
contains several branches and tags pointing somewhere into the middle
of the commit DAG, and thus result in a better name for the
to-be-named commit. This can hide bugs: e.g. by replacing the
'new_name' parameter of the first recursive name_rev() call with
'tip_name' (effectively making both branch #1 and #2 a noop) 'git
name-rev --all' shows thousands of bogus names in the Git repository,
but the whole test suite still passes successfully. In an early
version of a later patch in this series I managed to mess up all three
branches (at once!), but the test suite still passed.
So add a new test case that operates on the following history:
A--------------master
\ /
\----------M2
\ /
\---M1-C
\ /
B
and names the commit 'B' to make sure that all three branches are
crucial to determine 'B's name:
- There is only a single ref, so all names are based on 'master',
without any undesired interference from other refs.
- Each time name_rev() follows the second parent of a merge commit,
it appends "^2" to the name. Following 'master's second parent
right at the start ensures that all commits on the ancestry path
from 'master' to 'B' have a different base name from the original
'tip_name' of the very first name_rev() invocation. Currently,
while name_rev() is recursive, it doesn't matter, but it will be
necessary to properly cover all three branches after the recursion
is eliminated later in this series.
- Following 'M2's second parent makes sure that branch #2 (i.e. when
'generation = 0') affects 'B's name.
- Following the only parent of the non-merge commit 'C' ensures that
branch #3 affects 'B's name, and that it increments 'generation'.
- Coming from 'C' 'generation' is 1, thus following 'M1's second
parent makes sure that branch #1 affects 'B's name.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The 'check_describe' helper function runs 'git describe' outside of
'test_expect_success' blocks, with extra hand-rolled code to record
and examine its exit code.
Update this helper and move the 'git describe' invocation inside the
'test_expect_success' block.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
At the top of 't6120-describe.sh' an ASCII graph illustrates the
repository's history used in this test script. This graph is a bit
misleading, because it swapped the second merge commit's first and
second parents.
When describing/naming a commit it does make a difference which parent
is the first and which is the second/Nth, so update this graph to
accurately represent that second merge.
While at it, move this history graph from the 'test_description'
variable to a regular comment.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When 'git name-rev' is invoked with commit-ish parameters, it tries to
save some work, and doesn't visit commits older than the committer
date of the oldest given commit minus a one day worth of slop. Since
our 'timestamp_t' is an unsigned type, this leads to a timestamp
underflow when the committer date of the oldest given commit is within
a day of the UNIX epoch. As a result the cutoff timestamp ends up
far-far in the future, and 'git name-rev' doesn't visit any commits,
and names each given commit as 'undefined'.
Check whether subtracting the slop from the oldest committer date
would lead to an underflow, and use no cutoff in that case. We don't
have a TIME_MIN constant, dddbad728c (timestamp_t: a new data type for
timestamps, 2017-04-26) didn't add one, so do it now.
Note that the type of the cutoff timestamp variable used to be signed
before 5589e87fd8 (name-rev: change a "long" variable to timestamp_t,
2017-05-20). The behavior was still the same even back then, but the
underflow didn't happen when substracting the slop from the oldest
committer date, but when comparing the signed cutoff timestamp with
unsigned committer dates in name_rev(). IOW, this underflow bug is as
old as 'git name-rev' itself.
Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fix widely supported but non-POSIX basic regex syntax introduced in
[1] and [2]. On GNU, NetBSD and FreeBSD the following works:
$ echo xy >f
$ grep 'xy\?' f; echo $?
xy
0
The same goes for "\+". The "?" and "+" syntax is not in the BRE
syntax, just in ERE, but on some implementations it can be invoked by
prefixing the meta-operator with "\", but not on OpenBSD:
$ uname -a
OpenBSD obsd.my.domain 6.2 GENERIC#132 amd64
$ grep --version
grep version 0.9
$ grep 'xy\?' f; echo $?
1
Let's fix this by moving to ERE syntax instead, where "?" and "+" are
universally supported:
$ grep -E 'xy?' f; echo $?
xy
0
1. 2ed5c8e174 ("describe: setup working tree for --dirty", 2019-02-03)
2. c801170b0c ("t6120: test for describe with a bare repository",
2019-02-03)
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git --work-tree=$there --git-dir=$here describe --dirty" did not
work correctly as it did not pay attention to the location of the
worktree specified by the user by mistake, which has been
corrected.
* ss/describe-dirty-in-the-right-directory:
t6120: test for describe with a bare repository
describe: setup working tree for --dirty
This ensures that nothing breaks the basic functionality of describe for
bare repositories. Please note that --broken and --dirty need a working
tree.
Signed-off-by: Sebastian Staudt <koraktor@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We don't use NEED_WORK_TREE when running the git-describe builtin,
since you should be able to describe a commit even in a bare repository.
However, the --dirty flag does need a working tree. Since we don't call
setup_work_tree(), it uses whatever directory we happen to be in. That's
unlikely to match our index, meaning we'd say "dirty" even when the real
working tree is clean.
We can fix that by calling setup_work_tree() once we know that the user
has asked for --dirty.
The --broken option also needs a working tree. But because its
implementation calls git-diff-index we don‘t have to setup the working
tree in the git-describe process.
Signed-off-by: Sebastian Staudt <koraktor@gmail.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Using 'test_must_be_empty' is shorter and more idiomatic than
>empty &&
test_cmp empty out
as it saves the creation of an empty file. Furthermore, sometimes the
expected empty file doesn't have such a descriptive name like 'empty',
and its creation is far away from the place where it's finally used
for comparison (e.g. in 't7600-merge.sh', where two expected empty
files are created in the 'setup' test, but are used only about 500
lines later).
These cases were found by instrumenting 'test_cmp' to error out the
test script when it's used to compare empty files, and then converted
manually.
Note that even after this patch there still remain a lot of cases
where we use 'test_cmp' to check empty files:
- Sometimes the expected output is not hard-coded in the test, but
'test_cmp' is used to ensure that two similar git commands produce
the same output, and that output happens to be empty, e.g. the
test 'submodule update --merge - ignores --merge for new
submodules' in 't7406-submodule-update.sh'.
- Repetitive common tasks, including preparing the expected results
and running 'test_cmp', are often extracted into a helper
function, and some of this helper's callsites expect no output.
- For the same reason as above, the whole 'test_expect_success'
block is within a helper function, e.g. in 't3070-wildmatch.sh'.
- Or 'test_cmp' is invoked in a loop, e.g. the test 'cvs update
(-p)' in 't9400-git-cvsserver-server.sh'.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Switch all uses of $_z40 to $ZERO_OID so that they work correctly with
larger hashes. This commit was created by using the following sed
command to modify all files in the t directory except t/test-lib.sh:
sed -i 's/\$_z40/$ZERO_OID/g'
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git describe $garbage" stopped giving any errors when the garbage
happens to be a string with 40 hexadecimal letters.
* sb/describe-blob:
describe: confirm that blobs actually exist
Prior to 644eb60bd0 (builtin/describe.c: describe a blob,
2017-11-15), we noticed and complained about missing
objects, since they were not valid commits:
$ git describe 0000000000000000000000000000000000000000
fatal: 0000000000000000000000000000000000000000 is not a valid 'commit' object
After that commit, we feed any non-commit to lookup_blob(),
and complain only if it returns NULL. But the lookup_*
functions do not actually look at the on-disk object
database at all. They return an entry from the in-memory
object hash if present (and if it matches the requested
type), and otherwise auto-create a "struct object" of the
requested type.
A missing object would hit that latter case: we create a
bogus blob struct, walk all of history looking for it, and
then exit successfully having produced no output.
One reason nobody may have noticed this is that some related
cases do still work OK:
1. If we ask for a tree by sha1, then the call to
lookup_commit_referecne_gently() would have parsed it,
and we would have its true type in the in-memory object
hash.
2. If we ask for a name that doesn't exist but isn't a
40-hex sha1, then get_oid() would complain before we
even look at the objects at all.
We can fix this by replacing the lookup_blob() call with a
check of the true type via sha1_object_info(). This is not
quite as efficient as we could possibly make this check. We
know in most cases that the object was already parsed in the
earlier commit lookup, so we could call lookup_object(),
which does auto-create, and check the resulting struct's
type (or NULL). However it's not worth the fragility nor
code complexity to save a single object lookup.
The new tests cover this case, as well as that of a
tree-by-sha1 (which does work as described above, but was
not explicitly tested).
Noticed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
An old regression in "git describe --all $annotated_tag^0" has been
fixed.
* dk/describe-all-output-fix:
describe: prepend "tags/" when describing tags with embedded name
The man page of the "git describe" command explains the expected
output when using the --all option, i.e. the full reference path is
shown, including heads/ or tags/ prefix.
When 212945d4a8 ("Teach git-describe
to verify annotated tag names before output") made Git favor the
embedded name of annotated tags, it accidentally changed the output
format when the --all flag is given, only printing the tag's name
without the prefix.
Check if --all was specified and re-add the "tags/" prefix for this
special case to fix the regresssion.
Signed-off-by: Daniel Knittl-Frank <knittl89+git@googlemail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Sometimes users are given a hash of an object and they want to
identify it further (ex.: Use verify-pack to find the largest blobs,
but what are these? or [1])
When describing commits, we try to anchor them to tags or refs, as these
are conceptually on a higher level than the commit. And if there is no ref
or tag that matches exactly, we're out of luck. So we employ a heuristic
to make up a name for the commit. These names are ambiguous, there might
be different tags or refs to anchor to, and there might be different
path in the DAG to travel to arrive at the commit precisely.
When describing a blob, we want to describe the blob from a higher layer
as well, which is a tuple of (commit, deep/path) as the tree objects
involved are rather uninteresting. The same blob can be referenced by
multiple commits, so how we decide which commit to use? This patch
implements a rather naive approach on this: As there are no back pointers
from blobs to commits in which the blob occurs, we'll start walking from
any tips available, listing the blobs in-order of the commit and once we
found the blob, we'll take the first commit that listed the blob. For
example
git describe --tags v0.99:Makefile
conversion-901-g7672db20c2:Makefile
tells us the Makefile as it was in v0.99 was introduced in commit 7672db20.
The walking is performed in reverse order to show the introduction of a
blob rather than its last occurrence.
[1] https://stackoverflow.com/questions/223678/which-commit-has-this-blob
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git describe --match <pattern>" has been taught to play well with
the "--all" option.
* mk/describe-match-with-all:
describe: teach --match to handle branches and remotes
"git describe --match" learned to take multiple patterns in v2.13
series, but the feature ignored the patterns after the first one
and did not work at all. This has been fixed.
* jk/describe-omit-some-refs:
describe: fix matching to actually match all patterns
When `git describe` uses `--match`, it matches only tags, basically
ignoring the `--all` argument even when it is specified.
Fix it by also matching branch name and $remote_name/$remote_branch_name,
for remote-tracking references, with the specified patterns. Update
documentation accordingly and add tests.
Signed-off-by: Max Kirillov <max@max630.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
`git describe --match` with multiple patterns matches only first pattern.
If it fails, next patterns are not tried.
Fix it, add test cases and update existing test which has wrong
expectation.
Signed-off-by: Max Kirillov <max@max630.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Elijah Newren