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714 Commits

Author SHA1 Message Date
Junio C Hamano 909d5b646e Merge branch 'vd/mv-refresh-stat'
"git mv" failed to refresh the cached stat information for the
entry it moved.

* vd/mv-refresh-stat:
  mv: refresh stat info for moved entry
2022-04-04 10:56:24 -07:00
Victoria Dye b7f9130a06 mv: refresh stat info for moved entry
Update the stat info of the moved index entry in 'rename_index_entry_at()'
if the entry is up-to-date with the index. Internally, 'git mv' uses
'rename_index_entry_at()' to move the source index entry to the destination.
However, it directly copies the stat info of the original cache entry, which
will not reflect the 'ctime' of the file renaming operation that happened as
part of the move. If a file is otherwise up-to-date with the index, that
difference in 'ctime' will make the entry appear out-of-date until the next
index-refreshing operation (e.g., 'git status').

Some commands, such as 'git reset', use the cached stat information to
determine whether a file is up-to-date; if this information is incorrect,
the command will fail when it should pass. In order to ensure a moved entry
is evaluated as 'up-to-date' when appropriate, refresh the destination index
entry's stat info in 'git mv' if and only if the file is up-to-date.

Note that the test added in 't7001-mv.sh' requires a "sleep 1" to ensure the
'ctime' of the file creation will be definitively older than the 'ctime' of
the renamed file in 'git mv'.

Reported-by: Maximilian Reichel <reichemn@icloud.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-29 09:45:02 -07:00
Junio C Hamano eb804cd405 Merge branch 'ns/core-fsyncmethod'
Replace core.fsyncObjectFiles with two new configuration variables,
core.fsync and core.fsyncMethod.

* ns/core-fsyncmethod:
  core.fsync: documentation and user-friendly aggregate options
  core.fsync: new option to harden the index
  core.fsync: add configuration parsing
  core.fsync: introduce granular fsync control infrastructure
  core.fsyncmethod: add writeout-only mode
  wrapper: make inclusion of Windows csprng header tightly scoped
2022-03-25 16:38:24 -07:00
Junio C Hamano 430883a70c Merge branch 'ab/object-file-api-updates'
Object-file API shuffling.

* ab/object-file-api-updates:
  object-file API: pass an enum to read_object_with_reference()
  object-file.c: add a literal version of write_object_file_prepare()
  object-file API: have hash_object_file() take "enum object_type"
  object API: rename hash_object_file_literally() to write_*()
  object-file API: split up and simplify check_object_signature()
  object API users + docs: check <0, not !0 with check_object_signature()
  object API docs: move check_object_signature() docs to cache.h
  object API: correct "buf" v.s. "map" mismatch in *.c and *.h
  object-file API: have write_object_file() take "enum object_type"
  object-file API: add a format_object_header() function
  object-file API: return "void", not "int" from hash_object_file()
  object-file.c: split up declaration of unrelated variables
2022-03-16 17:53:08 -07:00
Neeraj Singh ba95e96d4c core.fsync: new option to harden the index
This commit introduces the new ability for the user to harden
the index. In the event of a system crash, the index must be
durable for the user to actually find a file that has been added
to the repo and then deleted from the working tree.

We use the presence of the COMMIT_LOCK flag and absence of the
alternate_index_output as a proxy for determining whether we're
updating the persistent index of the repo or some temporary
index. We don't sync these temporary indexes.

Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-10 15:10:22 -08:00
Neeraj Singh 020406eaa5 core.fsync: introduce granular fsync control infrastructure
This commit introduces the infrastructure for the core.fsync
configuration knob. The repository components we want to sync
are identified by flags so that we can turn on or off syncing
for specific components.

If core.fsyncObjectFiles is set and the core.fsync configuration
also includes FSYNC_COMPONENT_LOOSE_OBJECT, we will fsync any
loose objects. This picks the strictest data integrity behavior
if core.fsync and core.fsyncObjectFiles are set to conflicting values.

This change introduces the currently unused fsync_component
helper, which will be used by a later patch that adds fsyncing to
the refs backend.

Actual configuration and documentation of the fsync components
list are in other patches in the series to separate review of
the underlying mechanism from the policy of how it's configured.

Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-03-10 15:10:22 -08:00
Ævar Arnfjörð Bjarmason c80d226a04 object-file API: have write_object_file() take "enum object_type"
Change the write_object_file() function to take an "enum object_type"
instead of a "const char *type". Its callers either passed
{commit,tree,blob,tag}_type and can pass the corresponding OBJ_* type
instead, or were hardcoding strings like "blob".

This avoids the back & forth fragility where the callers of
write_object_file() would have the enum type, and convert it
themselves via type_name(). We do have to now do that conversion
ourselves before calling write_object_file_prepare(), but those
codepaths will be similarly adjusted in subsequent commits.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-02-25 17:16:31 -08:00
Junio C Hamano 2f45f3e2bc Merge branch 'vd/sparse-clean-etc'
"git update-index", "git checkout-index", and "git clean" are
taught to work better with the sparse checkout feature.

* vd/sparse-clean-etc:
  update-index: reduce scope of index expansion in do_reupdate
  update-index: integrate with sparse index
  update-index: add tests for sparse-checkout compatibility
  checkout-index: integrate with sparse index
  checkout-index: add --ignore-skip-worktree-bits option
  checkout-index: expand sparse checkout compatibility tests
  clean: integrate with sparse index
  reset: reorder wildcard pathspec conditions
  reset: fix validation in sparse index test
2022-02-17 16:25:05 -08:00
Junio C Hamano 1b82b936e3 Merge branch 'js/sparse-vs-split-index'
Mark in various places in the code that the sparse index and the
split index features are mutually incompatible.

* js/sparse-vs-split-index:
  split-index: it really is incompatible with the sparse index
  t1091: disable split index
  sparse-index: sparse index is disallowed when split index is active
2022-02-09 14:21:01 -08:00
Junio C Hamano c70bc338e9 Merge branch 'ab/config-based-hooks-2'
More "config-based hooks".

* ab/config-based-hooks-2:
  run-command: remove old run_hook_{le,ve}() hook API
  receive-pack: convert push-to-checkout hook to hook.h
  read-cache: convert post-index-change to use hook.h
  commit: convert {pre-commit,prepare-commit-msg} hook to hook.h
  git-p4: use 'git hook' to run hooks
  send-email: use 'git hook run' for 'sendemail-validate'
  git hook run: add an --ignore-missing flag
  hooks: convert worktree 'post-checkout' hook to hook library
  hooks: convert non-worktree 'post-checkout' hook to hook library
  merge: convert post-merge to use hook.h
  am: convert applypatch-msg to use hook.h
  rebase: convert pre-rebase to use hook.h
  hook API: add a run_hooks_l() wrapper
  am: convert {pre,post}-applypatch to use hook.h
  gc: use hook library for pre-auto-gc hook
  hook API: add a run_hooks() wrapper
  hook: add 'run' subcommand
2022-02-09 14:21:00 -08:00
Johannes Schindelin 451b66c533 split-index: it really is incompatible with the sparse index
... at least for now. So let's error out if we are even trying to
initialize the split index when the index is sparse, or when trying to
write the split index extension for a sparse index.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-23 17:06:23 -08:00
Victoria Dye c35e9f5ecd update-index: integrate with sparse index
Enable use of the sparse index with `update-index`. Most variations of
`update-index` work without explicitly expanding the index or making any
other updates in or outside of `update-index.c`.

The one usage requiring additional changes is `--cacheinfo`; if a file
inside a sparse directory was specified, the index would not be expanded
until after the cache tree is invalidated, leading to a mismatch between the
index and cache tree. This scenario is handled by rearranging
`add_index_entry_with_check`, allowing `index_name_stage_pos` to expand the
index *before* attempting to invalidate the relevant cache tree path,
avoiding cache tree/index corruption.

Signed-off-by: Victoria Dye <vdye@github.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-13 13:49:45 -08:00
Emily Shaffer dbb1c61365 read-cache: convert post-index-change to use hook.h
Move the post-index-change hook away from run-command.h to and over to
the new hook.h library.

This removes the last direct user of "run_hook_ve()" outside of
run-command.c ("run_hook_le()" still uses it). So we can make the
function static now. A subsequent commit will remove this code
entirely when "run_hook_le()" itself goes away.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Emily Shaffer <emilyshaffer@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-07 15:19:35 -08:00
Marc Strapetz 2ede073fd2 update-index: refresh should rewrite index in case of racy timestamps
'git update-index --refresh' and '--really-refresh' should force writing
of the index file if racy timestamps have been encountered, as
'git status' already does [1].

Note that calling 'git update-index --refresh' still does not guarantee
that there will be no more racy timestamps afterwards (the same holds
true for 'git status'):

- calling 'git update-index --refresh' immediately after touching and
  adding a file may still leave racy timestamps if all three operations
  occur within the racy-tolerance (usually 1 second unless USE_NSEC has
  been defined)

- calling 'git update-index --refresh' for timestamps which are set into
  the future will leave them racy

To guarantee that such racy timestamps will be resolved would require to
wait until the system clock has passed beyond these timestamps and only
then write the index file. Especially for future timestamps, this does
not seem feasible because of possibly long delays/hangs.

[1] https://lore.kernel.org/git/d3dd805c-7c1d-30a9-6574-a7bfcb7fc013@syntevo.com/

Signed-off-by: Marc Strapetz <marc.strapetz@syntevo.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-01-07 12:37:31 -08:00
Junio C Hamano f0850875fd Merge branch 'vd/sparse-reset'
Various operating modes of "git reset" have been made to work
better with the sparse index.

* vd/sparse-reset:
  unpack-trees: improve performance of next_cache_entry
  reset: make --mixed sparse-aware
  reset: make sparse-aware (except --mixed)
  reset: integrate with sparse index
  reset: expand test coverage for sparse checkouts
  sparse-index: update command for expand/collapse test
  reset: preserve skip-worktree bit in mixed reset
  reset: rename is_missing to !is_in_reset_tree
2021-12-10 14:35:12 -08:00
Junio C Hamano 5396d7b298 Merge branch 'vd/sparse-sparsity-fix-on-read'
Ensure that the sparseness of the in-core index matches the
index.sparse configuration specified by the repository immediately
after the on-disk index file is read.

* vd/sparse-sparsity-fix-on-read:
  sparse-index: update do_read_index to ensure correct sparsity
  sparse-index: add ensure_correct_sparsity function
  sparse-index: avoid unnecessary cache tree clearing
  test-read-cache.c: prepare_repo_settings after config init
2021-12-10 14:35:01 -08:00
Victoria Dye 20ec2d034c reset: make sparse-aware (except --mixed)
Remove `ensure_full_index` guard on `prime_cache_tree` and update
`prime_cache_tree_rec` to correctly reconstruct sparse directory entries in
the cache tree. While processing a tree's entries, `prime_cache_tree_rec`
must determine whether a directory entry is sparse or not by searching for
it in the index (*without* expanding the index). If a matching sparse
directory index entry is found, no subtrees are added to the cache tree
entry and the entry count is set to 1 (representing the sparse directory
itself). Otherwise, the tree is assumed to not be sparse and its subtrees
are recursively added to the cache tree.

Helped-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-29 12:51:26 -08:00
Victoria Dye 7ca4fc8819 sparse-index: update do_read_index to ensure correct sparsity
Unless `command_requires_full_index` forces index expansion, ensure in-core
index sparsity matches config settings on read by calling
`ensure_correct_sparsity`. This makes the behavior of the in-core index more
consistent between different methods of updating sparsity: manually changing
the `index.sparse` config setting vs. executing
`git sparse-checkout --[no-]sparse-index init`

Although index sparsity is normally updated with `git sparse-checkout init`,
ensuring correct sparsity after a manual `index.sparse` change has some
practical benefits:

1. It allows for command-by-command sparsity toggling with
   `-c index.sparse=<true|false>`, e.g. when troubleshooting issues with the
   sparse index.
2. It prevents users from experiencing abnormal slowness after setting
   `index.sparse` to `true` due to use of a full index in all commands until
   the on-disk index is updated.

Helped-by: Junio C Hamano <gitster@pobox.com>
Co-authored-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Victoria Dye <vdye@github.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-24 16:32:39 -08:00
Junio C Hamano 6ffb5fc069 Merge branch 'rs/add-dry-run-without-objects'
Stop "git add --dry-run" from creating new blob and tree objects.

* rs/add-dry-run-without-objects:
  add: don't write objects with --dry-run
2021-10-25 16:06:57 -07:00
Junio C Hamano a86ed75f32 Merge branch 'rs/make-verify-path-really-verify-again'
Recent sparse-index work broke safety against attempts to add paths
with trailing slashes to the index, which has been corrected.

* rs/make-verify-path-really-verify-again:
  read-cache: let verify_path() reject trailing dir separators again
  read-cache: add verify_path_internal()
  t3905: show failure to ignore sub-repo
2021-10-18 15:47:58 -07:00
René Scharfe e578d0311d add: don't write objects with --dry-run
When the option --dry-run/-n is given, "git add" doesn't change the
index, but still writes out new object files.  Only hash the latter
without writing instead to make the run as dry as possible.

Use this opportunity to also make the hash_flags variable unsigned,
to match the index_path() parameter it is used as.

Reported-by: git.mexon@spamgourmet.com
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-12 13:15:49 -07:00
Junio C Hamano ed4d535342 Merge branch 'sg/test-split-index-fix'
Test updates.

* sg/test-split-index-fix:
  read-cache: fix GIT_TEST_SPLIT_INDEX
  tests: disable GIT_TEST_SPLIT_INDEX for sparse index tests
  read-cache: look for shared index files next to the index, too
  t1600-index: disable GIT_TEST_SPLIT_INDEX
  t1600-index: don't run git commands upstream of a pipe
  t1600-index: remove unnecessary redirection
2021-10-11 10:21:47 -07:00
René Scharfe c8ad9d04c6 read-cache: let verify_path() reject trailing dir separators again
6e773527b6 (sparse-index: convert from full to sparse, 2021-03-30) made
verify_path() accept trailing directory separators for directories,
which is necessary for sparse directory entries.  This clemency causes
"git stash" to stumble over sub-repositories, though, and there may be
more unintended side-effects.

Avoid them by restoring the old verify_path() behavior and accepting
trailing directory separators only in places that are supposed to handle
sparse directory entries.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-07 17:52:26 -07:00
René Scharfe 2a1ae649a4 read-cache: add verify_path_internal()
Turn verify_path() into an internal function that distinguishes between
valid paths and those with trailing directory separators and rename it
to verify_path_internal().  Provide a wrapper with the old behavior
under the old name.  No functional change intended.  The new function
will be used in the next patch.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-10-07 17:49:39 -07:00
Junio C Hamano d8d33378ed Merge branch 'ab/repo-settings-cleanup'
Code cleanup.

* ab/repo-settings-cleanup:
  repository.h: don't use a mix of int and bitfields
  repo-settings.c: simplify the setup
  read-cache & fetch-negotiator: check "enum" values in switch()
  environment.c: remove test-specific "ignore_untracked..." variable
  wrapper.c: add x{un,}setenv(), and use xsetenv() in environment.c
2021-10-06 13:40:11 -07:00
Ævar Arnfjörð Bjarmason 3050b6dfc7 repo-settings.c: simplify the setup
Simplify the setup code in repo-settings.c in various ways, making the
code shorter, easier to read, and requiring fewer hacks to do the same
thing as it did before:

Since 7211b9e753 (repo-settings: consolidate some config settings,
2019-08-13) we have memset() the whole "settings" structure to -1 in
prepare_repo_settings(), and subsequently relied on the -1 value.

Most of the fields did not need to be initialized to -1, and because
we were doing that we had the enum labels "UNTRACKED_CACHE_UNSET" and
"FETCH_NEGOTIATION_UNSET" purely to reflect the resulting state
created this memset() in prepare_repo_settings(). No other code used
or relied on them, more on that below.

For the rest most of the subsequent "are we -1, then read xyz" can
simply be removed by re-arranging what we read first. E.g. when
setting the "index.version" setting we should have first read
"feature.experimental", so that it (and "feature.manyfiles") can
provide a default for our "index.version".

Instead the code setting it, added when "feature.manyFiles"[1] was
created, was using the UPDATE_DEFAULT_BOOL() macro added in an earlier
commit[2]. That macro is now gone, since it was only needed for this
pattern of reading things in the wrong order.

This also fixes an (admittedly obscure) logic error where we'd
conflate an explicit "-1" value in the config with our own earlier
memset() -1.

We can also remove the UPDATE_DEFAULT_BOOL() wrapper added in
[3]. Using it is redundant to simply using the return value from
repo_config_get_bool(), which is non-zero if the provided key exists
in the config.

Details on edge cases relating to the memset() to -1, continued from
"more on that below" above:

 * UNTRACKED_CACHE_KEEP:

   In [4] the "unset" and "keep" handling for core.untrackedCache was
   consolidated. But it while we understand the "keep" value, we don't
   handle it differently than the case of any other unknown value.

   So let's retain UNTRACKED_CACHE_KEEP and remove the
   UNTRACKED_CACHE_UNSET setting (which was always implicitly
   UNTRACKED_CACHE_KEEP before). We don't need to inform any code
   after prepare_repo_settings() that the setting was "unset", as far
   as anyone else is concerned it's core.untrackedCache=keep. if
   "core.untrackedcache" isn't present in the config.

 * FETCH_NEGOTIATION_UNSET & FETCH_NEGOTIATION_NONE:

   Since these two two enum fields added in [5] don't rely on the
   memzero() setting them to "-1" anymore we don't have to provide
   them with explicit values.

1. c6cc4c5afd (repo-settings: create feature.manyFiles setting,
   2019-08-13)
2. 31b1de6a09 (commit-graph: turn on commit-graph by default,
   2019-08-13)
3. 31b1de6a09 (commit-graph: turn on commit-graph by default,
   2019-08-13)
4. ad0fb65999 (repo-settings: parse core.untrackedCache,
   2019-08-13)
5. aaf633c2ad (repo-settings: create feature.experimental setting,
   2019-08-13)

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-22 13:15:00 -07:00
Ævar Arnfjörð Bjarmason f1bee82873 read-cache & fetch-negotiator: check "enum" values in switch()
Change tweak_untracked_cache() in "read-cache.c" to use a switch() to
have the compiler assert that we checked all possible values in the
"enum untracked_cache_setting" type, and likewise remove the "default"
case in fetch_negotiator_init() in favor of checking for
"FETCH_NEGOTIATION_UNSET" and "FETCH_NEGOTIATION_NONE".

As will be discussed in a subsequent we'll only ever have either of
these set to FETCH_NEGOTIATION_NONE, FETCH_NEGOTIATION_UNSET and
UNTRACKED_CACHE_UNSET within the prepare_repo_settings() function
itself. In preparation for fixing that code let's add a BUG() here to
mark this as unreachable code.

See ad0fb65999 (repo-settings: parse core.untrackedCache, 2019-08-13)
for when the "unset" and "keep" handling for core.untrackedCache was
consolidated, and aaf633c2ad (repo-settings: create
feature.experimental setting, 2019-08-13) for the addition of the
"default" pattern in "fetch-negotiator.c".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-22 13:15:00 -07:00
SZEDER Gábor e8ffd034c8 read-cache: fix GIT_TEST_SPLIT_INDEX
Running tests with GIT_TEST_SPLIT_INDEX=1 is supposed to turn on the
split index feature and trigger index splitting (mostly) randomly.
Alas, this has been broken since 6e37c8ed3c (read-cache.c: fix writing
"link" index ext with null base oid, 2019-02-13), and
GIT_TEST_SPLIT_INDEX=1 hasn't triggered any index splitting since
then.

This patch makes GIT_TEST_SPLIT_INDEX work again, though it doesn't
restore the pre-6e37c8ed3c behavior.  To understand the bug, the fix,
and the behavior change we first have to look at how
GIT_TEST_SPLIT_INDEX used to work before 6e37c8ed3c:

  There are two places where we check the value of
  GIT_TEST_SPLIT_INDEX, and before 6e37c8ed3c they worked like this:

    1) In the lower-level do_write_index(), where, if
       GIT_TEST_SPLIT_INDEX is enabled, we call init_split_index().
       This call merely allocates and zero-initializes
       'istate->split_index', but does nothing else (i.e. doesn't fill
       the base/shared index with cache entries, doesn't actually
       write a shared index file, etc.).  Pertinent to this issue, the
       hash of the base index remains all zeroed out.

    2) In the higher-level write_locked_index(), but only when
       'istate->split_index' has already been initialized.  Then, if
       GIT_TEST_SPLIT_INDEX is enabled, it randomly sets the flag that
       triggers index splitting later in this function.  This
       randomness comes from the first byte of the hash of the base
       index via an 'if ((first_byte & 15) < 6)' condition.

       However, if 'istate->split_index' hasn't been initialized (i.e.
       it is still NULL), then write_locked_index() just calls
       do_write_locked_index(), which internally calls the above
       mentioned do_write_index().

  This means that while GIT_TEST_SPLIT_INDEX=1 usually triggered index
  splitting randomly, the first two index writes were always
  deterministic (though I suspect this was unintentional):

    - The initial index write never splits the index.
      During the first index write write_locked_index() is called with
      'istate->split_index' still uninitialized, so the check in 2) is
      not executed.  It still calls do_write_index(), though, which
      then executes the check in 1).  The resulting all zero base
      index hash then leads to the 'link' extension being written to
      '.git/index', though a shared index file is not written:

        $ rm .git/index
        $ GIT_TEST_SPLIT_INDEX=1 git update-index --add file
        $ test-tool dump-split-index .git/index
        own c6ef71168597caec8553c83d9d0048f1ef416170
        base 0000000000000000000000000000000000000000
        100644 d00491fd7e5bb6fa28c517a0bb32b8b506539d4d 0 file
        replacements:
        deletions:
        $ ls -l .git/sharedindex.*
        ls: cannot access '.git/sharedindex.*': No such file or directory

    - The second index write always splits the index.
      When the index written in the previous point is read,
      'istate->split_index' is initialized because of the presence of
      the 'link' extension.  So during the second write
      write_locked_index() does run the check in 2), and the first
      byte of the all zero base index hash always fulfills the
      randomness condition, which in turn always triggers the index
      splitting.

    - Subsequent index writes will find the 'link' extension with a
      real non-zero base index hash, so from then on the check in 2)
      is executed and the first byte of the base index hash is as
      random as it gets (coming from the SHA-1 of index data including
      timestamps and inodes...).

All this worked until 6e37c8ed3c came along, and stopped writing the
'link' extension if the hash of the base index was all zero:

  $ rm .git/index
  $ GIT_TEST_SPLIT_INDEX=1 git update-index --add file
  $ test-tool dump-split-index .git/index
  own abbd6f6458d5dee73ae8e210ca15a68a390c6fd7
  not a split index
  $ ls -l .git/sharedindex.*
  ls: cannot access '.git/sharedindex.*': No such file or directory

So, since the first index write with GIT_TEST_SPLIT_INDEX=1 doesn't
write a 'link' extension, in the second index write
'istate->split_index' remains uninitialized, and the check in 2) is
not executed, and ultimately the index is never split.

Fix this by modifying write_locked_index() to make sure to check
GIT_TEST_SPLIT_INDEX even if 'istate->split_index' is still
uninitialized, and initialize it if necessary.  The check for
GIT_TEST_SPLIT_INDEX and separate init_split_index() call in
do_write_index() thus becomes unnecessary, so remove it.  Furthermore,
add a test to 't1700-split-index.sh' to make sure that
GIT_TEST_SPLIT_INDEX=1 will keep working (though only check the
index splitting on the first index write, because after that it will
be random).

Note that this change does not restore the pre-6e37c8ed3c behaviour,
as it will deterministically split the index already on the first
index write.  Since GIT_TEST_SPLIT_INDEX is purely a developer aid,
there is no backwards compatibility issue here.  The new behaviour did
trigger test failures in 't0003-attributes.sh' and 't1600-index.sh',
though, which have been fixed in preparatory patches in this series.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Acked-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-07 23:28:04 -07:00
SZEDER Gábor 998330ac2e read-cache: look for shared index files next to the index, too
When reading a split index git always looks for its referenced shared
base index in the gitdir of the current repository, even when reading
an alternate index specified via GIT_INDEX_FILE, and even when that
alternate index file is the "main" '.git/index' file of an other
repository.  However, if that split index and its referenced shared
index files were written by a git command running entirely in that
other repository, then, naturally, the shared index file is written to
that other repository's gitdir.  Consequently, a git command
attempting to read that shared index file while running in a different
repository won't be able find it and will error out.

I'm not sure in what use case it is necessary to read the index of one
repository by a git command running in a different repository, but it
is certainly possible to do so, and in fact the test 'bare repository:
check that --cached honors index' in 't0003-attributes.sh' does
exactly that.  If GIT_TEST_SPLIT_INDEX=1 were to split the index in
just the right moment [1], then this test would indeed fail, because
the referenced shared index file could not be found.

Let's look for the referenced shared index file not only in the gitdir
of the current directory, but, if the shared index is not there, right
next to the split index as well.

[1] We haven't seen this issue trigger a failure in t0003 yet,
    because:

      - While GIT_TEST_SPLIT_INDEX=1 is supposed to trigger index
        splitting randomly, the first index write has always been
        deterministic and it has never split the index.

      - That alternate index file in the other repository is written
        only once in the entire test script, so it's never split.

    However, the next patch will fix GIT_TEST_SPLIT_INDEX, and while
    doing so it will slightly change its behavior to always split the
    index already on the first index write, and t0003 would always
    fail without this patch.

Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Acked-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-07 23:23:47 -07:00
Derrick Stolee ce7a9f0141 sparse-index: add SPARSE_INDEX_MEMORY_ONLY flag
The convert_to_sparse() method checks for the GIT_TEST_SPARSE_INDEX
environment variable or the "index.sparse" config setting before
converting the index to a sparse one. This is for ease of use since all
current consumers are preparing to compress the index before writing it
to disk. If these settings are not enabled, then convert_to_sparse()
silently returns without doing anything.

We will add a consumer in the next change that wants to use the sparse
index as an in-memory data structure, regardless of whether the on-disk
format should be sparse.

To that end, create the SPARSE_INDEX_MEMORY_ONLY flag that will skip
these config checks when enabled. All current consumers are modified to
pass '0' in the new 'flags' parameter.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-07 22:41:10 -07:00
Junio C Hamano 31f9acf9ce Merge branch 'ah/plugleaks'
Leak plugging.

* ah/plugleaks:
  reset: clear_unpack_trees_porcelain to plug leak
  builtin/rebase: fix options.strategy memory lifecycle
  builtin/merge: free found_ref when done
  builtin/mv: free or UNLEAK multiple pointers at end of cmd_mv
  convert: release strbuf to avoid leak
  read-cache: call diff_setup_done to avoid leak
  ref-filter: also free head for ATOM_HEAD to avoid leak
  diffcore-rename: move old_dir/new_dir definition to plug leak
  builtin/for-each-repo: remove unnecessary argv copy to plug leak
  builtin/submodule--helper: release unused strbuf to avoid leak
  environment: move strbuf into block to plug leak
  fmt-merge-msg: free newly allocated temporary strings when done
2021-08-04 13:28:52 -07:00
Junio C Hamano 8230107f33 Merge branch 'jt/bulk-prefetch'
"git read-tree" had a codepath where blobs are fetched one-by-one
from the promisor remote, which has been corrected to fetch in bulk.

* jt/bulk-prefetch:
  cache-tree: prefetch in partial clone read-tree
  unpack-trees: refactor prefetching code
2021-08-02 14:06:42 -07:00
Junio C Hamano b271a3034f Merge branch 'ds/status-with-sparse-index'
"git status" codepath learned to work with sparsely populated index
without hydrating it fully.

* ds/status-with-sparse-index:
  t1092: document bad sparse-checkout behavior
  fsmonitor: integrate with sparse index
  wt-status: expand added sparse directory entries
  status: use sparse-index throughout
  status: skip sparse-checkout percentage with sparse-index
  diff-lib: handle index diffs with sparse dirs
  dir.c: accept a directory as part of cone-mode patterns
  unpack-trees: unpack sparse directory entries
  unpack-trees: rename unpack_nondirectories()
  unpack-trees: compare sparse directories correctly
  unpack-trees: preserve cache_bottom
  t1092: add tests for status/add and sparse files
  t1092: expand repository data shape
  t1092: replace incorrect 'echo' with 'cat'
  sparse-index: include EXTENDED flag when expanding
  sparse-index: skip indexes with unmerged entries
2021-07-28 13:18:02 -07:00
Andrzej Hunt 8d833e9337 read-cache: call diff_setup_done to avoid leak
repo_diff_setup() calls through to diff.c's static prep_parse_options(),
which in  turn allocates a new array into diff_opts.parseopts.
diff_setup_done() is responsible for freeing that array, and has the
benefit of verifying diff_opts too - hence we add a call to
diff_setup_done() to avoid leaking parseopts.

Output from the leak as found while running t0090 with LSAN:

Direct leak of 7120 byte(s) in 1 object(s) allocated from:
    #0 0x49a82d in malloc ../projects/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3
    #1 0xa8bf89 in do_xmalloc wrapper.c:41:8
    #2 0x7a7bae in prep_parse_options diff.c:5636:2
    #3 0x7a7bae in repo_diff_setup diff.c:4611:2
    #4 0x93716c in repo_index_has_changes read-cache.c:2518:3
    #5 0x872233 in unclean merge-ort-wrappers.c:12:14
    #6 0x872233 in merge_ort_recursive merge-ort-wrappers.c:53:6
    #7 0x5d5b11 in try_merge_strategy builtin/merge.c:752:12
    #8 0x5d0b6b in cmd_merge builtin/merge.c:1666:9
    #9 0x4ce83e in run_builtin git.c:475:11
    #10 0x4ccafe in handle_builtin git.c:729:3
    #11 0x4cb01c in run_argv git.c:818:4
    #12 0x4cb01c in cmd_main git.c:949:19
    #13 0x6bdc2d in main common-main.c:52:11
    #14 0x7f551eb51349 in __libc_start_main (/lib64/libc.so.6+0x24349)

SUMMARY: AddressSanitizer: 7120 byte(s) leaked in 1 allocation(s)

Signed-off-by: Andrzej Hunt <andrzej@ahunt.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-26 12:19:20 -07:00
Jonathan Tan b2896d2739 unpack-trees: refactor prefetching code
Refactor the prefetching code in unpack-trees.c into its own function,
because it will be used elsewhere in a subsequent commit.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-23 14:21:57 -07:00
Junio C Hamano a93c6fd677 Merge branch 'ew/mmap-failures'
Error message update.

* ew/mmap-failures:
  xmmap: inform Linux users of tuning knobs on ENOMEM
2021-07-16 17:42:47 -07:00
Derrick Stolee d76723ee53 status: use sparse-index throughout
By testing 'git -c core.fsmonitor= status -uno', we can check for the
simplest index operations that can be made sparse-aware. The necessary
implementation details are already integrated with sparse-checkout, so
modify command_requires_full_index to be zero for cmd_status().

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

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

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

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

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

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

Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-14 13:42:49 -07:00
Junio C Hamano 2134c3fb1f Merge branch 'ab/progress-cleanup'
Code clean-up.

* ab/progress-cleanup:
  read-cache.c: don't guard calls to progress.c API
2021-07-08 13:15:05 -07:00
Eric Wong dc05929411 xmmap: inform Linux users of tuning knobs on ENOMEM
Linux users may benefit from additional information on how to
avoid ENOMEM from mmap despite the system having enough RAM to
accomodate them.  We can't reliably unmap pack windows to work
around the issue since malloc and other library routines may
mmap without our knowledge.

Signed-off-by: Eric Wong <e@80x24.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-06-29 23:14:25 -07:00
Ævar Arnfjörð Bjarmason b7b793d1e7 read-cache.c: don't guard calls to progress.c API
Don't guard the calls to the progress.c API with "if (progress)". The
API itself will check this. This doesn't change any behavior, but
makes this code consistent with the rest of the codebase.

See ae9af12287 (status: show progress bar if refreshing the index
takes too long, 2018-09-15) for the commit that added the pattern
we're changing here.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-06-08 10:09:13 +09:00
Derrick Stolee f6e2cd0625 read-cache: delete unused hashing methods
These methods were marked as MAYBE_UNUSED in the previous change to
avoid a complicated diff. Delete them entirely, since we now use the
hashfile API instead of this custom hashing code.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-19 16:41:21 +09:00
Derrick Stolee 410334ed52 read-cache: use hashfile instead of git_hash_ctx
The do_write_index() method in read-cache.c has its own hashing logic
and buffering mechanism. Specifically, the ce_write() method was
introduced by 4990aadc (Speed up index file writing by chunking it
nicely, 2005-04-20) and similar mechanisms were introduced a few months
later in c38138cd (git-pack-objects: write the pack files with a SHA1
csum, 2005-06-26). Based on the timing, in the early days of the Git
codebase, I figured that these roughly equivalent code paths were never
unified only because it got lost in the shuffle. The hashfile API has
since been used extensively in other file formats, such as pack-indexes,
multi-pack-indexes, and commit-graphs. Therefore, it seems prudent to
unify the index writing code to use the same mechanism.

I discovered this disparity while trying to create a new index format
that uses the chunk-format API. That API uses a hashfile as its base, so
it is incompatible with the custom code in read-cache.c.

This rewrite is rather straightforward. It replaces all writes to the
temporary file with writes to the hashfile struct. This takes care of
many of the direct interactions with the_hash_algo.

There are still some git_hash_ctx uses remaining: the extension headers
are hashed for use in the End of Index Entries (EOIE) extension. This
use of the git_hash_ctx is left as-is. There are multiple reasons to not
use a hashfile here, including the fact that the data is not actually
writing to a file, just a hash computation. These hashes do not block
our adoption of the chunk-format API in a future change to the index, so
leave it as-is.

The internals of the algorithms are mostly identical. Previously, the
hashfile API used a smaller 8KB buffer instead of the 128KB buffer from
read-cache.c. The previous change already unified these sizes.

There is one subtle point: we do not pass the CSUM_FSYNC to the
finalize_hashfile() method, which differs from most consumers of the
hashfile API. The extra fsync() call indicated by this flag causes a
significant peformance degradation that is noticeable for quick
commands that write the index, such as "git add". Other consumers can
absorb this cost with their more complicated data structure
organization, and further writing structures such as pack-files and
commit-graphs is rarely in the critical path for common user
interactions.

Some static methods become orphaned in this diff, so I marked them as
MAYBE_UNUSED. The diff is much harder to read if they are deleted during
this change. Instead, they will be deleted in the following change.

In addition to the test suite passing, I computed indexes using the
previous binaries and the binaries compiled after this change, and found
the index data to be exactly equal. Finally, I did extensive performance
testing of "git update-index --force-write" on repos of various sizes,
including one with over 2 million paths at HEAD. These tests
demonstrated less than 1% difference in behavior. As expected, the
performance should be considered unchanged. The previous changes to
increase the hashfile buffer size from 8K to 128K ensured this change
would not create a peformance regression.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-19 16:41:21 +09:00
Junio C Hamano a737e1f1d2 Merge branch 'mt/parallel-checkout-part-3'
The final part of "parallel checkout".

* mt/parallel-checkout-part-3:
  ci: run test round with parallel-checkout enabled
  parallel-checkout: add tests related to .gitattributes
  t0028: extract encoding helpers to lib-encoding.sh
  parallel-checkout: add tests related to path collisions
  parallel-checkout: add tests for basic operations
  checkout-index: add parallel checkout support
  builtin/checkout.c: complete parallel checkout support
  make_transient_cache_entry(): optionally alloc from mem_pool
2021-05-16 21:05:23 +09:00
Junio C Hamano aaa3c8065d Merge branch 'bc/hash-transition-interop-part-1'
SHA-256 transition.

* bc/hash-transition-interop-part-1:
  hex: print objects using the hash algorithm member
  hex: default to the_hash_algo on zero algorithm value
  builtin/pack-objects: avoid using struct object_id for pack hash
  commit-graph: don't store file hashes as struct object_id
  builtin/show-index: set the algorithm for object IDs
  hash: provide per-algorithm null OIDs
  hash: set, copy, and use algo field in struct object_id
  builtin/pack-redundant: avoid casting buffers to struct object_id
  Use the final_oid_fn to finalize hashing of object IDs
  hash: add a function to finalize object IDs
  http-push: set algorithm when reading object ID
  Always use oidread to read into struct object_id
  hash: add an algo member to struct object_id
2021-05-10 16:59:46 +09:00
Junio C Hamano fe069dce62 Merge branch 'mt/add-rm-in-sparse-checkout'
"git add" and "git rm" learned not to touch those paths that are
outside of sparse checkout.

* mt/add-rm-in-sparse-checkout:
  rm: honor sparse checkout patterns
  add: warn when asked to update SKIP_WORKTREE entries
  refresh_index(): add flag to ignore SKIP_WORKTREE entries
  pathspec: allow to ignore SKIP_WORKTREE entries on index matching
  add: make --chmod and --renormalize honor sparse checkouts
  t3705: add tests for `git add` in sparse checkouts
  add: include magic part of pathspec on --refresh error
2021-05-07 12:47:40 +09:00
Junio C Hamano bb2feec17f Merge branch 'ad/cygwin-no-backslashes-in-paths'
Cygwin pathname handling fix.

* ad/cygwin-no-backslashes-in-paths:
  cygwin: disallow backslashes in file names
2021-05-07 12:47:39 +09:00
Matheus Tavares 9616882780 make_transient_cache_entry(): optionally alloc from mem_pool
Allow make_transient_cache_entry() to optionally receive a mem_pool
struct in which it should allocate the entry. This will be used in the
following patch, to store some transient entries which should persist
until parallel checkout finishes.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-05 12:25:25 +09:00
Junio C Hamano 8e97852919 Merge branch 'ds/sparse-index-protections'
Builds on top of the sparse-index infrastructure to mark operations
that are not ready to mark with the sparse index, causing them to
fall back on fully-populated index that they always have worked with.

* ds/sparse-index-protections: (47 commits)
  name-hash: use expand_to_path()
  sparse-index: expand_to_path()
  name-hash: don't add directories to name_hash
  revision: ensure full index
  resolve-undo: ensure full index
  read-cache: ensure full index
  pathspec: ensure full index
  merge-recursive: ensure full index
  entry: ensure full index
  dir: ensure full index
  update-index: ensure full index
  stash: ensure full index
  rm: ensure full index
  merge-index: ensure full index
  ls-files: ensure full index
  grep: ensure full index
  fsck: ensure full index
  difftool: ensure full index
  commit: ensure full index
  checkout: ensure full index
  ...
2021-04-30 13:50:26 +09:00
Adam Dinwoodie bccc37fdc7 cygwin: disallow backslashes in file names
The backslash character is not a valid part of a file name on Windows.
If, in Windows, Git attempts to write a file that has a backslash
character in the filename, it will be incorrectly interpreted as a
directory separator.

This caused CVE-2019-1354 in MinGW, as this behaviour can be manipulated
to cause the checkout to write to files it ought not write to, such as
adding code to the .git/hooks directory.  This was fixed by e1d911dd4c
(mingw: disallow backslash characters in tree objects' file names,
2019-09-12).  However, the vulnerability also exists in Cygwin: while
Cygwin mostly provides a POSIX-like path system, it will still interpret
a backslash as a directory separator.

To avoid this vulnerability, CVE-2021-29468, extend the previous fix to
also apply to Cygwin.

Similarly, extend the test case added by the previous version of the
commit.  The test suite doesn't have an easy way to say "run this test
if in MinGW or Cygwin", so add a new test prerequisite that covers both.

As well as checking behaviour in the presence of paths containing
backslashes, the existing test also checks behaviour in the presence of
paths that differ only by the presence of a trailing ".".  MinGW follows
normal Windows application behaviour and treats them as the same path,
but Cygwin more closely emulates *nix systems (at the expense of
compatibility with native Windows applications) and will create and
distinguish between such paths.  Gate the relevant bit of that test
accordingly.

Reported-by: RyotaK <security@ryotak.me>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Adam Dinwoodie <adam@dinwoodie.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-30 09:49:20 +09:00
brian m. carlson 92e2cab96b Always use oidread to read into struct object_id
In the future, we'll want oidread to automatically set the hash
algorithm member for an object ID we read into it, so ensure we use
oidread instead of hashcpy everywhere we're copying a hash value into a
struct object_id.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-27 16:31:38 +09:00