Commit Graph

60803 Commits

Author SHA1 Message Date
Luke Diamand
677fa8d115 git-p4 unshelve: adding a commit breaks git-p4 unshelve
git-p4 unshelve uses HEAD^$n to find the parent commit, which
fails if there is an additional commit.

Signed-off-by: Luke Diamand <luke@diamand.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-19 13:44:54 -07:00
René Scharfe
389cf68caf pack-write: use hashwrite_be32() in write_idx_file()
Call hashwrite_be32() instead of open-coding it.  This shortens the code
a bit and makes it easier to read.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-19 12:15:36 -07:00
Junio C Hamano
385c171a01 Fifteenth batch
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18 17:58:06 -07:00
Junio C Hamano
80cacaec41 Merge branch 'mt/config-fail-nongit-early'
Unlike "git config --local", "git config --worktree" did not fail
early and cleanly when started outside a git repository.

* mt/config-fail-nongit-early:
  config: complain about --worktree outside of a git repo
2020-09-18 17:58:06 -07:00
Junio C Hamano
52bcf6e181 Merge branch 'jc/dist-tarball-tweak'
Allow maintainers to tweak $(TAR) invocations done while making
distribution tarballs.

* jc/dist-tarball-tweak:
  Makefile: allow extra tweaking of distribution tarball
2020-09-18 17:58:05 -07:00
Junio C Hamano
4831c23f75 Merge branch 'mf/submodule-summary-with-correct-repository'
"git diff/show" on a change that involves a submodule used to read
the information on commits in the submodule from a wrong repository
and gave a wrong information when the commit-graph is involved.

* mf/submodule-summary-with-correct-repository:
  submodule: use submodule repository when preparing summary
  revision: use repository from rev_info when parsing commits
2020-09-18 17:58:05 -07:00
Junio C Hamano
9d4e7ec4d9 Merge branch 'jc/quote-path-cleanup'
"git status --short" quoted a path with SP in it when tracked, but
not those that are untracked, ignored or unmerged.  They are all
shown quoted consistently.

* jc/quote-path-cleanup:
  quote: turn 'nodq' parameter into a set of flags
  quote: rename misnamed sq_lookup[] to cq_lookup[]
  wt-status: consistently quote paths in "status --short" output
  quote_path: code clarification
  quote_path: optionally allow quoting a path with SP in it
  quote_path: give flags parameter to quote_path()
  quote_path: rename quote_path_relative() to quote_path()
2020-09-18 17:58:04 -07:00
Junio C Hamano
2ce9d4e5c7 Merge branch 'os/collect-changed-submodules-optim'
Optimization around submodule handling.

* os/collect-changed-submodules-optim:
  submodule: suppress checking for file name and ref ambiguity for object ids
2020-09-18 17:58:04 -07:00
Junio C Hamano
45f462b5c5 Merge branch 'es/wt-add-detach'
"git worktree add" learns that the "-d" is a synonym to "--detach"
option to create a new worktree without being on a branch.

* es/wt-add-detach:
  git-worktree.txt: discuss branch-based vs. throwaway worktrees
  worktree: teach `add` to recognize -d as shorthand for --detach
  git-checkout.txt: document -d short option for --detach
2020-09-18 17:58:04 -07:00
Junio C Hamano
694e517778 Merge branch 'jk/add-i-fixes'
"add -i/-p" fixes.

* jk/add-i-fixes:
  add--interactive.perl: specify --no-color explicitly
  add-patch: fix inverted return code of repo_read_index()
2020-09-18 17:58:04 -07:00
Junio C Hamano
3ad8d3e4f9 Merge branch 'pw/add-p-leakfix'
Leakfix.

* pw/add-p-leakfix:
  add -p: fix memory leak
2020-09-18 17:58:03 -07:00
Junio C Hamano
e96b271d18 Merge branch 'jc/add-i-use-builtin-experimental'
The "add -i/-p" machinery has been written in C but it is not used
by default yet.  It is made default to those who are participating
in feature.experimental experiment.

* jc/add-i-use-builtin-experimental:
  add -i: use the built-in version when feature.experimental is set
2020-09-18 17:58:02 -07:00
Junio C Hamano
e41500ac19 Merge branch 'al/t3200-back-on-a-branch'
Test fix.

* al/t3200-back-on-a-branch:
  t3200: clean side effect of git checkout --orphan
2020-09-18 17:58:02 -07:00
Junio C Hamano
711f5b3ce2 Merge branch 'hn/refs-ref-log-only-bit'
A bit of API reshuffling to make sure stuff common to all backends
are not defined only in files backend.

* hn/refs-ref-log-only-bit:
  refs: move REF_LOG_ONLY to refs-internal.h
2020-09-18 17:58:01 -07:00
Junio C Hamano
e1dd499513 Merge branch 'ea/blame-use-oideq'
Code cleanup.

* ea/blame-use-oideq:
  blame.c: replace instance of !oidcmp for oideq
2020-09-18 17:58:01 -07:00
Junio C Hamano
4f4cb66b09 Merge branch 'pb/clang-json-compilation-database'
Developer support.

* pb/clang-json-compilation-database:
  Makefile: add support for generating JSON compilation database
2020-09-18 17:58:00 -07:00
Junio C Hamano
e46544454a Merge branch 'so/log-tree-diff-cleanup'
Code cleanup.

* so/log-tree-diff-cleanup:
  log_tree_diff: get rid of extra check for NULL
  log_tree_diff: get rid of code duplication for first_parent_only
2020-09-18 17:58:00 -07:00
Junio C Hamano
2496da4211 Merge branch 'rs/parallel-read-cache-fix'
A follow-up fix to a topic already in 'master'.

* rs/parallel-read-cache-fix:
  read-cache: fix mem-pool allocation for multi-threaded index loading
2020-09-18 17:58:00 -07:00
Junio C Hamano
21de7e9c50 Merge branch 'rs/refspec-leakfix'
Leakfix.

* rs/refspec-leakfix:
  refspec: add and use refspec_appendf()
  push: release strbufs used for refspec formatting
2020-09-18 17:58:00 -07:00
Junio C Hamano
9b8074427b Merge branch 'rs/misc-cleanups'
Misc cleanups.

* rs/misc-cleanups:
  pack-bitmap-write: use hashwrite_be32() in write_hash_cache()
  midx: use hashwrite_u8() in write_midx_header()
  fast-import: use write_pack_header()
2020-09-18 17:58:00 -07:00
Aaron Lipman
b59cdffd7e Doc: prefer more specific file name
Change filters.txt to ref-reachability-filters.txt in order to avoid
squatting on a file name that might be useful for another purpose.

Signed-off-by: Aaron Lipman <alipman88@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18 15:41:56 -07:00
Aaron Lipman
a1b19aa5d4 ref-filter: make internal reachable-filter API more precise
The internal reachable-filter API is a bit loose and imprecise; it
also bleeds unnecessarily into the public header. Tighten the API
by:

* renaming do_merge_filter() to reach_filter()

* separating parameters to explicitly identify what data is used
  by the function instead of passing an entire ref_filter_cbdata
  struct

* renaming and moving internal constants from header to source
  file

Signed-off-by: Aaron Lipman <alipman88@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18 15:41:55 -07:00
Taylor Blau
d356d5debe commit-graph: introduce 'commitGraph.maxNewFilters'
Introduce a configuration variable to specify a default value for the
recently-introduce '--max-new-filters' option of 'git commit-graph
write'.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18 10:39:22 -07:00
Taylor Blau
809e0327f5 builtin/commit-graph.c: introduce '--max-new-filters=<n>'
Introduce a command-line flag to specify the maximum number of new Bloom
filters that a 'git commit-graph write' is willing to compute from
scratch.

Prior to this patch, a commit-graph write with '--changed-paths' would
compute Bloom filters for all selected commits which haven't already
been computed (i.e., by a previous commit-graph write with '--split'
such that a roll-up or replacement is performed).

This behavior can cause prohibitively-long commit-graph writes for a
variety of reasons:

  * There may be lots of filters whose diffs take a long time to
    generate (for example, they have close to the maximum number of
    changes, diffing itself takes a long time, etc).

  * Old-style commit-graphs (which encode filters with too many entries
    as not having been computed at all) cause us to waste time
    recomputing filters that appear to have not been computed only to
    discover that they are too-large.

This can make the upper-bound of the time it takes for 'git commit-graph
write --changed-paths' to be rather unpredictable.

To make this command behave more predictably, introduce
'--max-new-filters=<n>' to allow computing at most '<n>' Bloom filters
from scratch. This lets "computing" already-known filters proceed
quickly, while bounding the number of slow tasks that Git is willing to
do.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18 10:35:39 -07:00
Taylor Blau
98bb796191 commit-graph: rename 'split_commit_graph_opts'
In the subsequent commit, additional options will be added to the
commit-graph API which have nothing to do with splitting.

Rename the 'split_commit_graph_opts' structure to the more-generic
'commit_graph_opts' to encompass both. Likewise, rename the 'flags'
member to instead be 'split_flags' to clarify that it only has to do
with the behavior implied by '--split'.

Suggested-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 21:55:50 -07:00
Taylor Blau
59f0d5073f bloom: encode out-of-bounds filters as non-empty
When a changed-path Bloom filter has either zero, or more than a
certain number (commonly 512) of entries, the commit-graph machinery
encodes it as "missing". More specifically, it sets the indices adjacent
in the BIDX chunk as equal to each other to indicate a "length 0"
filter; that is, that the filter occupies zero bytes on disk.

This has heretofore been fine, since the commit-graph machinery has no
need to care about these filters with too few or too many changed paths.
Both cases act like no filter has been generated at all, and so there is
no need to store them.

In a subsequent commit, however, the commit-graph machinery will learn
to only compute Bloom filters for some commits in the current
commit-graph layer. This is a change from the current implementation
which computes Bloom filters for all commits that are in the layer being
written. Critically for this patch, only computing some of the Bloom
filters means adding a third state for length 0 Bloom filters: zero
entries, too many entries, or "hasn't been computed".

It will be important for that future patch to distinguish between "not
representable" (i.e., zero or too-many changed paths), and "hasn't been
computed". In particular, we don't want to waste time recomputing
filters that have already been computed.

To that end, change how we store Bloom filters in the "computed but not
representable" category:

  - Bloom filters with no entries are stored as a single byte with all
    bits low (i.e., all queries to that Bloom filter will return
    "definitely not")

  - Bloom filters with too many entries are stored as a single byte with
    all bits set high (i.e., all queries to that Bloom filter will
    return "maybe").

These rules are sufficient to not incur a behavior change by changing
the on-disk representation of these two classes. Likewise, no
specification changes are necessary for the commit-graph format, either:

  - Filters that were previously empty will be recomputed and stored
    according to the new rules, and

  - old clients reading filters generated by new clients will interpret
    the filters correctly and be none the wiser to how they were
    generated.

Clients will invoke the Bloom machinery in more cases than before, but
this can be addressed by returning a NULL filter when all bits are set
high. This can be addressed in a future patch.

Note that this does increase the size of on-disk commit-graphs, but far
less than other proposals. In particular, this is generally more
efficient than storing a bitmap for which commits haven't computed their
Bloom filters. Storing a bitmap incurs a penalty of one bit per commit,
whereas storing explicit filters as above incurs a penalty of one byte
per too-large or empty commit.

In practice, these boundary commits likely occupy a small proportion of
the overall number of commits, and so the size penalty is likely smaller
than storing a bitmap for all commits.

See, for example, these relative proportions of such boundary commits
(collected by SZEDER Gábor):

                  |     Percentage of     |    commit-graph   |           |
                  |   commits modifying   |     file size     |           |
                  ├────────┬──────────────┼───────────────────┤    pct.   |
                  | 0 path | >= 512 paths | before  |  after  |   change  |
 ┌────────────────┼────────┼──────────────┼─────────┼─────────┼───────────┤
 | android-base   | 13.20% |        0.13% | 37.468M | 37.534M | +0.1741 % |
 | cmssw          |  0.15% |        0.23% | 17.118M | 17.119M | +0.0091 % |
 | cpython        |  3.07% |        0.01% |  7.967M |  7.971M | +0.0423 % |
 | elasticsearch  |  0.70% |        1.00% |  8.833M |  8.835M | +0.0128 % |
 | gcc            |  0.00% |        0.08% | 16.073M | 16.074M | +0.0030 % |
 | gecko-dev      |  0.14% |        0.64% | 59.868M | 59.874M | +0.0105 % |
 | git            |  0.11% |        0.02% |  3.895M |  3.895M | +0.0020 % |
 | glibc          |  0.02% |        0.10% |  3.555M |  3.555M | +0.0021 % |
 | go             |  0.00% |        0.07% |  3.186M |  3.186M | +0.0018 % |
 | homebrew-cask  |  0.40% |        0.02% |  7.035M |  7.035M | +0.0065 % |
 | homebrew-core  |  0.01% |        0.01% | 11.611M | 11.611M | +0.0002 % |
 | jdk            |  0.26% |        5.64% |  5.537M |  5.540M | +0.0590 % |
 | linux          |  0.01% |        0.51% | 63.735M | 63.740M | +0.0073 % |
 | llvm-project   |  0.12% |        0.03% | 25.515M | 25.516M | +0.0050 % |
 | rails          |  0.10% |        0.10% |  6.252M |  6.252M | +0.0027 % |
 | rust           |  0.07% |        0.17% |  9.364M |  9.364M | +0.0033 % |
 | tensorflow     |  0.09% |        1.02% |  7.009M |  7.010M | +0.0158 % |
 | webkit         |  0.05% |        0.31% | 17.405M | 17.406M | +0.0047 % |

(where the above increase is determined by computing a non-split
commit-graph before and after this patch).

Given that these projects are all "large" by commit count, the storage
cost by writing these filters explicitly is negligible. In the most
extreme example, android-base (which has 494,848 commits at the time of
writing) would have its commit-graph increase by a modest 68.4 KB.

Finally, a test to exercise filters which contain too many changed path
entries will be introduced in a subsequent patch.

Suggested-by: SZEDER Gábor <szeder.dev@gmail.com>
Suggested-by: Jakub Narębski <jnareb@gmail.com>
Helped-by: Derrick Stolee <dstolee@microsoft.com>
Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 21:55:50 -07:00
Denton Liu
93ab00bd85 contrib/completion: complete options that take refs for format-patch
The completion for format-patch currently suggests --base=, --interdiff=
and --range-diff= as options. However, with these `=` forms of the
options, there is no space and we'd enter the `--*` case which means we
don't call the __git_complete_revlist() at the end.

Teach _git_format_patch() to complete refs in the case of --base=,
--interdiff= and --range-diff=.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 15:23:22 -07:00
Christian Schlack
5a07c6c3c2 remote: don't show success message when set-head fails
Suppress the message 'origin/HEAD set to master' in case of an error.

  $ git remote set-head origin -a
  error: Not a valid ref: refs/remotes/origin/master
  origin/HEAD set to master

Signed-off-by: Christian Schlack <christian@backhub.co>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:40:17 -07:00
Jeff King
67bb65de5d packfile: actually set approximate_object_count_valid
The approximate_object_count() function tries to compute the count only
once per process. But ever since it was introduced in 8e3f52d778
(find_unique_abbrev: move logic out of get_short_sha1(), 2016-10-03), we
failed to actually set the "valid" flag, meaning we'd compute it fresh
on every call.

This turns out not to be _too_ bad, because we're only iterating through
the packed_git list, and not making any system calls. But since it may
get called for every abbreviated hash we output, even this can add up if
you have many packs.

Here are before-and-after timings for a new perf test which just asks
rev-list to abbreviate each commit hash (the test repo is linux.git,
with commit-graphs):

  Test                            origin              HEAD
  ----------------------------------------------------------------------------
  5303.3: rev-list (1)            28.91(28.46+0.44)   29.03(28.65+0.38) +0.4%
  5303.4: abbrev-commit (1)       1.18(1.06+0.11)     1.17(1.02+0.14) -0.8%
  5303.7: rev-list (50)           28.95(28.56+0.38)   29.50(29.17+0.32) +1.9%
  5303.8: abbrev-commit (50)      3.67(3.56+0.10)     3.57(3.42+0.15) -2.7%
  5303.11: rev-list (1000)        30.34(29.89+0.43)   30.82(30.35+0.46) +1.6%
  5303.12: abbrev-commit (1000)   86.82(86.52+0.29)   77.82(77.59+0.22) -10.4%
  5303.15: load 10,000 packs      0.08(0.02+0.05)     0.08(0.02+0.06) +0.0%

It doesn't help at all when we have 1 pack (5303.4), but we get a 10%
speedup when there are 1000 packs (5303.12). That's a modest speedup for
a case that's already slow and we'd hope to avoid in general (note how
slow it is even after, because we have to look in each of those packs
for abbreviations). But it's a one-line change that clearly matches the
original intent, so it seems worth doing.

The included perf test may also be useful for keeping an eye on any
regressions in the overall abbreviation code.

Reported-by: Rasmus Villemoes <rv@rasmusvillemoes.dk>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:36:14 -07:00
Derrick Stolee
25914c4fde maintenance: add trace2 regions for task execution
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Derrick Stolee
4ddc79b2da maintenance: add auto condition for commit-graph task
Instead of writing a new commit-graph in every 'git maintenance run
--auto' process (when maintenance.commit-graph.enalbed is configured to
be true), only write when there are "enough" commits not in a
commit-graph file.

This count is controlled by the maintenance.commit-graph.auto config
option.

To compute the count, use a depth-first search starting at each ref, and
leaving markers using the SEEN flag. If this count reaches the limit,
then terminate early and start the task. Otherwise, this operation will
peel every ref and parse the commit it points to. If these are all in
the commit-graph, then this is typically a very fast operation. Users
with many refs might feel a slow-down, and hence could consider updating
their limit to be very small. A negative value will force the step to
run every time.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Derrick Stolee
916d0626c2 maintenance: use pointers to check --auto
The 'git maintenance run' command has an '--auto' option. This is used
by other Git commands such as 'git commit' or 'git fetch' to check if
maintenance should be run after adding data to the repository.

Previously, this --auto option was only used to add the argument to the
'git gc' command as part of the 'gc' task. We will be expanding the
other tasks to perform a check to see if they should do work as part of
the --auto flag, when they are enabled by config.

First, update the 'gc' task to perform the auto check inside the
maintenance process. This prevents running an extra 'git gc --auto'
command when not needed. It also shows a model for other tasks.

Second, use the 'auto_condition' function pointer as a signal for
whether we enable the maintenance task under '--auto'. For instance, we
do not want to enable the 'fetch' task in '--auto' mode, so that
function pointer will remain NULL.

Now that we are not automatically calling 'git gc', a test in
t5514-fetch-multiple.sh must be changed to watch for 'git maintenance'
instead.

We continue to pass the '--auto' option to the 'git gc' command when
necessary, because of the gc.autoDetach config option changes behavior.
Likely, we will want to absorb the daemonizing behavior implied by
gc.autoDetach as a maintenance.autoDetach config option.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Derrick Stolee
65d655b52d maintenance: create maintenance.<task>.enabled config
Currently, a normal run of "git maintenance run" will only run the 'gc'
task, as it is the only one enabled. This is mostly for backwards-
compatible reasons since "git maintenance run --auto" commands replaced
previous "git gc --auto" commands after some Git processes. Users could
manually run specific maintenance tasks by calling "git maintenance run
--task=<task>" directly.

Allow users to customize which steps are run automatically using config.
The 'maintenance.<task>.enabled' option then can turn on these other
tasks (or turn off the 'gc' task).

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Derrick Stolee
d7514f6ed5 maintenance: take a lock on the objects directory
Performing maintenance on a Git repository involves writing data to the
.git directory, which is not safe to do with multiple writers attempting
the same operation. Ensure that only one 'git maintenance' process is
running at a time by holding a file-based lock. Simply the presence of
the .git/maintenance.lock file will prevent future maintenance. This
lock is never committed, since it does not represent meaningful data.
Instead, it is only a placeholder.

If the lock file already exists, then no maintenance tasks are
attempted. This will become very important later when we implement the
'prefetch' task, as this is our stop-gap from creating a recursive process
loop between 'git fetch' and 'git maintenance run --auto'.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Derrick Stolee
090511bc0b maintenance: add --task option
A user may want to only run certain maintenance tasks in a certain
order. Add the --task=<task> option, which allows a user to specify an
ordered list of tasks to run. These cannot be run multiple times,
however.

Here is where our array of maintenance_task pointers becomes critical.
We can sort the array of pointers based on the task order, but we do not
want to move the struct data itself in order to preserve the hashmap
references. We use the hashmap to match the --task=<task> arguments into
the task struct data.

Keep in mind that the 'enabled' member of the maintenance_task struct is
a placeholder for a future 'maintenance.<task>.enabled' config option.
Thus, we use the 'enabled' member to specify which tasks are run when
the user does not specify any --task=<task> arguments. The 'enabled'
member should be ignored if --task=<task> appears.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Derrick Stolee
663b2b1b90 maintenance: add commit-graph task
The first new task in the 'git maintenance' builtin is the
'commit-graph' task. This updates the commit-graph file
incrementally with the command

	git commit-graph write --reachable --split

By writing an incremental commit-graph file using the "--split"
option we minimize the disruption from this operation. The default
behavior is to merge layers until the new "top" layer is less than
half the size of the layer below. This provides quick writes most
of the time, with the longer writes following a power law
distribution.

Most importantly, concurrent Git processes only look at the
commit-graph-chain file for a very short amount of time, so they
will verly likely not be holding a handle to the file when we try
to replace it. (This only matters on Windows.)

If a concurrent process reads the old commit-graph-chain file, but
our job expires some of the .graph files before they can be read,
then those processes will see a warning message (but not fail).
This could be avoided by a future update to use the --expire-time
argument when writing the commit-graph.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Derrick Stolee
3103e9848f maintenance: initialize task array
In anticipation of implementing multiple maintenance tasks inside the
'maintenance' builtin, use a list of structs to describe the work to be
done.

The struct maintenance_task stores the name of the task (as given by a
future command-line argument) along with a function pointer to its
implementation and a boolean for whether the step is enabled.

A list these structs are initialized with the full list of implemented
tasks along with a default order. For now, this list only contains the
"gc" task. This task is also the only task enabled by default.

The run subcommand will return a nonzero exit code if any task fails.
However, it will attempt all tasks in its loop before returning with the
failure. Also each failed task will print an error message.

Helped-by: Taylor Blau <me@ttaylorr.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Derrick Stolee
a95ce12430 maintenance: replace run_auto_gc()
The run_auto_gc() method is used in several places to trigger a check
for repo maintenance after some Git commands, such as 'git commit' or
'git fetch'.

To allow for extra customization of this maintenance activity, replace
the 'git gc --auto [--quiet]' call with one to 'git maintenance run
--auto [--quiet]'. As we extend the maintenance builtin with other
steps, users will be able to select different maintenance activities.

Rename run_auto_gc() to run_auto_maintenance() to be clearer what is
happening on this call, and to expose all callers in the current diff.
Rewrite the method to use a struct child_process to simplify the calls
slightly.

Since 'git fetch' already allows disabling the 'git gc --auto'
subprocess, add an equivalent option with a different name to be more
descriptive of the new behavior: '--[no-]maintenance'. Update the
documentation to include these options at the same time.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Derrick Stolee
3ddaad0e06 maintenance: add --quiet option
Maintenance activities are commonly used as steps in larger scripts.
Providing a '--quiet' option allows those scripts to be less noisy when
run on a terminal window. Turn this mode on by default when stderr is
not a terminal.

Pipe the option to the 'git gc' child process.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:05 -07:00
Derrick Stolee
2057d75038 maintenance: create basic maintenance runner
The 'gc' builtin is our current entrypoint for automatically maintaining
a repository. This one tool does many operations, such as repacking the
repository, packing refs, and rewriting the commit-graph file. The name
implies it performs "garbage collection" which means several different
things, and some users may not want to use this operation that rewrites
the entire object database.

Create a new 'maintenance' builtin that will become a more general-
purpose command. To start, it will only support the 'run' subcommand,
but will later expand to add subcommands for scheduling maintenance in
the background.

For now, the 'maintenance' builtin is a thin shim over the 'gc' builtin.
In fact, the only option is the '--auto' toggle, which is handed
directly to the 'gc' builtin. The current change is isolated to this
simple operation to prevent more interesting logic from being lost in
all of the boilerplate of adding a new builtin.

Use existing builtin/gc.c file because we want to share code between the
two builtins. It is possible that we will have 'maintenance' replace the
'gc' builtin entirely at some point, leaving 'git gc' as an alias for
some specific arguments to 'git maintenance run'.

Create a new test_subcommand helper that allows us to test if a certain
subcommand was run. It requires storing the GIT_TRACE2_EVENT logs in a
file. A negation mode is available that will be used in later tests.

Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 11:30:04 -07:00
Derrick Stolee
b16a827764 bloom/diff: properly short-circuit on max_changes
Commit e3696980 (diff: halt tree-diff early after max_changes,
2020-03-30) intended to create a mechanism to short-circuit a diff
calculation after a certain number of paths were modified. By
incrementing a "num_changes" counter throughout the recursive
ll_diff_tree_paths(), this was supposed to match the number of changes
that would be written into the changed-path Bloom filters.
Unfortunately, this was not implemented correctly and instead misses
simple cases like file modifications. This then does not stop very
large changed-path filters from being written (unless they add or remove
many files).

To start, change the implementation in ll_diff_tree_paths() to instead
use the global diff_queue_diff struct's 'nr' member as the count. This
is a way to simplify the logic instead of making more mistakes in the
complicated diff code.

This has a drawback: the diff_queue_diff struct only lists the paths
corresponding to blob changes, not their leading directories. Thus,
get_or_compute_bloom_filter() needs an additional check to see if the
hashmap with the leading directories becomes too large.

One reason why this was not caught by test cases was that the test in
t4216-log-bloom.sh that was supposed to check this "too many changes"
condition only checked this on the initial commit of a repository. The
old logic counted these values correctly. Update this test in a few
ways:

1. Use GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS to reduce the limit,
   allowing smaller commits to engage with this logic.

2. Create several interesting cases of edits, adds, removes, and mode
   changes (in the second commit). By testing both sides of the
   inequality with the *_MAX_CHANGED_PATHS variable, we can see that
   the count is exactly correct, so none of these changes are missed
   or over-counted.

3. Use the trace2 data value filter_found_large to verify that these
   commits are on the correct side of the limit.

Another way to verify the behavior is correct is through performance
tests. By testing on my local copies of the Git repository and the Linux
kernel repository, I could measure the effect of these short-circuits
when computing a fresh commit-graph file with changed-path Bloom filters
using the command

  GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS=N time \
    git commit-graph write --reachable --changed-paths

and reporting the wall time and resulting commit-graph size.

For Git, the results are

|        |      N=1       |       N=10     |      N=512     |
|--------|----------------|----------------|----------------|
| HEAD~1 | 10.90s  9.18MB | 11.11s  9.34MB | 11.31s  9.35MB |
| HEAD   |  9.21s  8.62MB | 11.11s  9.29MB | 11.29s  9.34MB |

For Linux, the results are

|        |       N=1      |     N=20      |     N=512     |
|--------|----------------|---------------|---------------|
| HEAD~1 | 61.28s  64.3MB | 76.9s  72.6MB | 77.6s  72.6MB |
| HEAD   | 49.44s  56.3MB | 68.7s  65.9MB | 69.2s  65.9MB |

Naturally, the improvement becomes much less as the limit grows, as
fewer commits satisfy the short-circuit.

Reported-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 09:31:25 -07:00
Taylor Blau
9a7a9ed10d bloom: use provided 'struct bloom_filter_settings'
When 'get_or_compute_bloom_filter()' needs to compute a Bloom filter
from scratch, it looks to the default 'struct bloom_filter_settings' in
order to determine the maximum number of changed paths, number of bits
per entry, and so on.

All of these values have so far been constant, and so there was no need
to pass in a pointer from the caller (eg., the one that is stored in the
'struct write_commit_graph_context').

Start passing in a 'struct bloom_filter_settings *' instead of using the
default values to respect graph-specific settings (eg., in the case of
setting 'GIT_TEST_BLOOM_SETTINGS_MAX_CHANGED_PATHS').

In order to have an initialized value for these settings, move its
initialization to earlier in the commit-graph write.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 09:31:25 -07:00
Taylor Blau
312cff5207 bloom: split 'get_bloom_filter()' in two
'get_bloom_filter' takes a flag to control whether it will compute a
Bloom filter if the requested one is missing. In the next patch, we'll
add yet another parameter to this method, which would force all but one
caller to specify an extra 'NULL' parameter at the end.

Instead of doing this, split 'get_bloom_filter' into two functions:
'get_bloom_filter' and 'get_or_compute_bloom_filter'. The former only
looks up a Bloom filter (and does not compute one if it's missing,
thus dropping the 'compute_if_not_present' flag). The latter does
compute missing Bloom filters, with an additional parameter to store
whether or not it needed to do so.

This simplifies many call-sites, since the majority of existing callers
to 'get_bloom_filter' do not want missing Bloom filters to be computed
(so they can drop the parameter entirely and use the simpler version of
the function).

While we're at it, instrument the new 'get_or_compute_bloom_filter()'
with counters in the 'write_commit_graph_context' struct which store
the number of filters that we did and didn't compute, as well as filters
that were truncated.

It would be nice to drop the 'compute_if_not_present' flag entirely,
since all remaining callers of 'get_or_compute_bloom_filter' pass it as
'1', but this will change in a future patch and hence cannot be removed.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 09:31:25 -07:00
Taylor Blau
97ffa4fab5 commit-graph.c: store maximum changed paths
For now, we assume that there is a fixed constant describing the
maximum number of changed paths we are willing to store in a Bloom
filter.

Prepare for that to (at least partially) not be the case by making it a
member of the 'struct bloom_filter_settings'. This will be helpful in
the subsequent patches by reducing the size of test cases that exercise
storing too many changed paths, as well as preparing for an eventual
future in which this value might change.

This patch alone does not cause newly generated Bloom filters to use
a custom upper-bound on the maximum number of changed paths a single
Bloom filter can hold, that will occur in a later patch.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17 09:29:22 -07:00
Lin Sun
dbd8c09bfe mergetool: allow auto-merge for meld to follow the vim-diff behavior
Make the mergetool used with "meld" backend behave similarly to "vimdiff" by
telling it to auto-merge non-conflicting parts and highlight the conflicting
parts when `mergetool.meld.useAutoMerge` is configured with `true`, or `auto`
for detecting the `--auto-merge` option automatically.

Helped-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Helped-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Lin Sun <lin.sun@zoom.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-16 17:11:20 -07:00
Ævar Arnfjörð Bjarmason
872977b10d remote-mediawiki doc: link to MediaWiki's current version
Amend a comment in the test.config file to point to the latest
upstream version, which makes it easier for the user to tweak this.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-16 16:11:53 -07:00
Ævar Arnfjörð Bjarmason
442f5aaccc remote-mediawiki doc: correct link to GitHub project
Change the link to the canonical one, the old link redirects to the
new one.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-16 16:11:53 -07:00
Aaron Lipman
21bf933928 ref-filter: allow merged and no-merged filters
Enable ref-filter to process multiple merged and no-merged filters, and
extend functionality to git branch, git tag and git for-each-ref. This
provides an easy way to check for branches that are "graduation
candidates:"

$ git branch --no-merged master --merged next

If passed more than one merged (or more than one no-merged) filter, refs
must be reachable from any one of the merged commits, and reachable from
none of the no-merged commits.

Signed-off-by: Aaron Lipman <alipman88@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-16 12:38:10 -07:00
Aaron Lipman
415af72b17 Doc: cover multiple contains/no-contains filters
Update documentation for "git branch", "git for-each-ref" and "git tag"
with notes explaining what happens when passed multiple --contains or
--no-contains filters.

This behavior is useful to document prior to enabling multiple
merged/no-merged filters, in order to demonstrate consistent behavior
between merged/no-merged and contains/no-contains filters.

Signed-off-by: Aaron Lipman <alipman88@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-16 12:38:09 -07:00
Aaron Lipman
b775d8122e t3201: test multiple branch filter combinations
Add tests covering the behavior of passing multiple contains/no-contains
filters to git branch, e.g.:

$ git branch --contains feature_a --contains feature_b
$ git branch --no-contains feature_a --no-contains feature_b

When passed more than one contains (or no-contains) filter, the tips of
the branches returned must be reachable from any of the contains commits
and from none of the the no-contains commits.

This logic is useful to describe prior to enabling multiple
merged/no-merged filters, so that future tests will demonstrate
consistent behavior between merged/no-merged and contains/no-contains
filters.

Signed-off-by: Aaron Lipman <alipman88@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-16 12:38:09 -07:00