cb99a34e23
The previous commit includes a failing test for an issue around
fetch.writeCommitGraph and fetching in a repo with a submodule. Here, we
fix that bug and set the test to "test_expect_success".
The problem arises with this set of commands when the remote repo at
<url> has a submodule. Note that --recurse-submodules is not needed to
demonstrate the bug.
$ git clone <url> test
$ cd test
$ git -c fetch.writeCommitGraph=true fetch origin
Computing commit graph generation numbers: 100% (12/12), done.
BUG: commit-graph.c:886: missing parent <hash1> for commit <hash2>
Aborted (core dumped)
As an initial fix, I converted the code in builtin/fetch.c that calls
write_commit_graph_reachable() to instead launch a "git commit-graph
write --reachable --split" process. That code worked, but is not how we
want the feature to work long-term.
That test did demonstrate that the issue must be something to do with
internal state of the 'git fetch' process.
The write_commit_graph() method in commit-graph.c ensures the commits we
plan to write are "closed under reachability" using close_reachable().
This method walks from the input commits, and uses the UNINTERESTING
flag to mark which commits have already been visited. This allows the
walk to take O(N) time, where N is the number of commits, instead of
O(P) time, where P is the number of paths. (The number of paths can be
exponential in the number of commits.)
However, the UNINTERESTING flag is used in lots of places in the
codebase. This flag usually means some barrier to stop a commit walk,
such as in revision-walking to compare histories. It is not often
cleared after the walk completes because the starting points of those
walks do not have the UNINTERESTING flag, and clear_commit_marks() would
stop immediately.
This is happening during a 'git fetch' call with a remote. The fetch
negotiation is comparing the remote refs with the local refs and marking
some commits as UNINTERESTING.
I tested running clear_commit_marks_many() to clear the UNINTERESTING
flag inside close_reachable(), but the tips did not have the flag, so
that did nothing.
It turns out that the calculate_changed_submodule_paths() method is at
fault. Thanks, Peff, for pointing out this detail! More specifically,
for each submodule, the collect_changed_submodules() runs a revision
walk to essentially do file-history on the list of submodules. That
revision walk marks commits UNININTERESTING if they are simplified away
by not changing the submodule.
Instead, I finally arrived on the conclusion that I should use a flag
that is not used in any other part of the code. In commit-reach.c, a
number of flags were defined for commit walk algorithms. The REACHABLE
flag seemed like it made the most sense, and it seems it was not
actually used in the file. The REACHABLE flag was used in early versions
of commit-reach.c, but was removed by
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| gitweb | ||
| mergetools | ||
| negotiator | ||
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| refs | ||
| sha1collisiondetection@855827c583 | ||
| sha1dc | ||
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| COPYING | ||
| GIT-VERSION-GEN | ||
| INSTALL | ||
| LGPL-2.1 | ||
| Makefile | ||
| README.md | ||
| RelNotes | ||
| abspath.c | ||
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| banned.h | ||
| base85.c | ||
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| blob.c | ||
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| builtin.h | ||
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| check-builtins.sh | ||
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| color.c | ||
| color.h | ||
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| column.h | ||
| combine-diff.c | ||
| command-list.txt | ||
| commit-graph.c | ||
| commit-graph.h | ||
| commit-reach.c | ||
| commit-reach.h | ||
| commit-slab-decl.h | ||
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| commit-slab.h | ||
| commit.c | ||
| commit.h | ||
| common-main.c | ||
| config.c | ||
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| configure.ac | ||
| connect.c | ||
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| copy.c | ||
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| credential-store.c | ||
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| credential.h | ||
| csum-file.c | ||
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| ctype.c | ||
| daemon.c | ||
| date.c | ||
| decorate.c | ||
| decorate.h | ||
| delta-islands.c | ||
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| delta.h | ||
| detect-compiler | ||
| diff-delta.c | ||
| diff-lib.c | ||
| diff-no-index.c | ||
| diff.c | ||
| diff.h | ||
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| diffcore-pickaxe.c | ||
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| diffcore.h | ||
| dir-iterator.c | ||
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| dir.c | ||
| dir.h | ||
| editor.c | ||
| entry.c | ||
| environment.c | ||
| exec-cmd.c | ||
| exec-cmd.h | ||
| fast-import.c | ||
| fetch-negotiator.c | ||
| fetch-negotiator.h | ||
| fetch-object.c | ||
| fetch-object.h | ||
| fetch-pack.c | ||
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| fmt-merge-msg.h | ||
| fsck.c | ||
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| fsmonitor.c | ||
| fsmonitor.h | ||
| fuzz-commit-graph.c | ||
| fuzz-pack-headers.c | ||
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| generate-cmdlist.sh | ||
| gettext.c | ||
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| git-add--interactive.perl | ||
| git-archimport.perl | ||
| git-bisect.sh | ||
| git-compat-util.h | ||
| git-cvsexportcommit.perl | ||
| git-cvsimport.perl | ||
| git-cvsserver.perl | ||
| git-difftool--helper.sh | ||
| git-filter-branch.sh | ||
| git-instaweb.sh | ||
| git-legacy-stash.sh | ||
| git-merge-octopus.sh | ||
| git-merge-one-file.sh | ||
| git-merge-resolve.sh | ||
| git-mergetool--lib.sh | ||
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| git-p4.py | ||
| git-parse-remote.sh | ||
| git-quiltimport.sh | ||
| git-rebase--preserve-merges.sh | ||
| git-request-pull.sh | ||
| git-send-email.perl | ||
| git-sh-i18n.sh | ||
| git-sh-setup.sh | ||
| git-submodule.sh | ||
| git-svn.perl | ||
| git-web--browse.sh | ||
| git.c | ||
| git.rc | ||
| gpg-interface.c | ||
| gpg-interface.h | ||
| graph.c | ||
| graph.h | ||
| grep.c | ||
| grep.h | ||
| hash.h | ||
| hashmap.c | ||
| hashmap.h | ||
| help.c | ||
| help.h | ||
| hex.c | ||
| http-backend.c | ||
| http-fetch.c | ||
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| http-walker.c | ||
| http.c | ||
| http.h | ||
| ident.c | ||
| imap-send.c | ||
| interdiff.c | ||
| interdiff.h | ||
| iterator.h | ||
| json-writer.c | ||
| json-writer.h | ||
| khash.h | ||
| kwset.c | ||
| kwset.h | ||
| levenshtein.c | ||
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| line-log.c | ||
| line-log.h | ||
| line-range.c | ||
| line-range.h | ||
| linear-assignment.c | ||
| linear-assignment.h | ||
| list-objects-filter-options.c | ||
| list-objects-filter-options.h | ||
| list-objects-filter.c | ||
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| list-objects.c | ||
| list-objects.h | ||
| list.h | ||
| ll-merge.c | ||
| ll-merge.h | ||
| lockfile.c | ||
| lockfile.h | ||
| log-tree.c | ||
| log-tree.h | ||
| ls-refs.c | ||
| ls-refs.h | ||
| mailinfo.c | ||
| mailinfo.h | ||
| mailmap.c | ||
| mailmap.h | ||
| match-trees.c | ||
| mem-pool.c | ||
| mem-pool.h | ||
| merge-blobs.c | ||
| merge-blobs.h | ||
| merge-recursive.c | ||
| merge-recursive.h | ||
| merge.c | ||
| mergesort.c | ||
| mergesort.h | ||
| midx.c | ||
| midx.h | ||
| name-hash.c | ||
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| notes-cache.h | ||
| notes-merge.c | ||
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| notes.c | ||
| notes.h | ||
| object-store.h | ||
| object.c | ||
| object.h | ||
| oidmap.c | ||
| oidmap.h | ||
| oidset.c | ||
| oidset.h | ||
| pack-bitmap-write.c | ||
| pack-bitmap.c | ||
| pack-bitmap.h | ||
| pack-check.c | ||
| pack-objects.c | ||
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| pack-revindex.c | ||
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| pack-write.c | ||
| pack.h | ||
| packfile.c | ||
| packfile.h | ||
| pager.c | ||
| parse-options-cb.c | ||
| parse-options.c | ||
| parse-options.h | ||
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| preload-index.c | ||
| pretty.c | ||
| pretty.h | ||
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| protocol.c | ||
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| reachable.c | ||
| reachable.h | ||
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| revision.c | ||
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| server-info.c | ||
| setup.c | ||
| sh-i18n--envsubst.c | ||
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| sha1-array.h | ||
| sha1-file.c | ||
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| shallow.c | ||
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README.md
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.txt
(man gitcvs-migration or git help cvs-migration if git is
installed).
The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission). To subscribe to the list, send an email with just "subscribe git" in the body to majordomo@vger.kernel.org. The mailing list archives are available at https://public-inbox.org/git/, http://marc.info/?l=git and other archival sites.
Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (depending on your mood):
- random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
- "global information tracker": you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks