git/setup.c, branch v2.28.1

Merge branch 'jn/v0-with-extensions-fix' into master

2020-07-17T00:58:42Z

In 2.28-rc0, we corrected a bug that some repository extensions are honored by mistake even in a version 0 repositories (these configuration variables in extensions.* namespace were supposed to have special meaning in repositories whose version numbers are 1 or higher), but this was a bit too big a change. * jn/v0-with-extensions-fix: repository: allow repository format upgrade with extensions Revert "check_repository_format_gently(): refuse extensions for old repositories"

repository: allow repository format upgrade with extensions

2020-07-16T16:36:39Z

Now that we officially permit repository extensions in repository format v0, permit upgrading a repository with extensions from v0 to v1 as well. For example, this means a repository where the user has set "extensions.preciousObjects" can use "git fetch --filter=blob:none origin" to upgrade the repository to use v1 and the partial clone extension. To avoid mistakes, continue to forbid repository format upgrades in v0 repositories with an unrecognized extension. This way, a v0 user using a misspelled extension field gets a chance to correct the mistake before updating to the less forgiving v1 format. While we're here, make the error message for failure to upgrade the repository format a bit shorter, and present it as an error, not a warning. Reported-by: Huan Huan Chen Signed-off-by: Jonathan Nieder Signed-off-by: Junio C Hamano

Revert "check_repository_format_gently(): refuse extensions for old repositories"

2020-07-16T16:36:37Z

This reverts commit 14c7fa269e42df4133edd9ae7763b678ed6594cd. The core.repositoryFormatVersion field was introduced in ab9cb76f661 (Repository format version check., 2005-11-25), providing a welcome bit of forward compatibility, thanks to some welcome analysis by Martin Atukunda. The semantics are simple: a repository with core.repositoryFormatVersion set to 0 should be comprehensible by all Git implementations in active use; and Git implementations should error out early instead of trying to act on Git repositories with higher core.repositoryFormatVersion values representing new formats that they do not understand. A new repository format did not need to be defined until 00a09d57eb8 (introduce "extensions" form of core.repositoryformatversion, 2015-06-23). This provided a finer-grained extension mechanism for Git repositories. In a repository with core.repositoryFormatVersion set to 1, Git implementations can act on "extensions.*" settings that modify how a repository is interpreted. In repository format version 1, unrecognized extensions settings cause Git to error out. What happens if a user sets an extension setting but forgets to increase the repository format version to 1? The extension settings were still recognized in that case; worse, unrecognized extensions settings do *not* cause Git to error out. So combining repository format version 0 with extensions settings produces in some sense the worst of both worlds. To improve that situation, since 14c7fa269e4 (check_repository_format_gently(): refuse extensions for old repositories, 2020-06-05) Git instead ignores extensions in v0 mode. This way, v0 repositories get the historical (pre-2015) behavior and maintain compatibility with Git implementations that do not know about the v1 format. Unfortunately, users had been using this sort of configuration and this behavior change came to many as a surprise: - users of "git config --worktree" that had followed its advice to enable extensions.worktreeConfig (without also increasing the repository format version) would find their worktree configuration no longer taking effect - tools such as copybara[*] that had set extensions.partialClone in existing repositories (without also increasing the repository format version) would find that setting no longer taking effect The behavior introduced in 14c7fa269e4 might be a good behavior if we were traveling back in time to 2015, but we're far too late. For some reason I thought that it was what had been originally implemented and that it had regressed. Apologies for not doing my research when 14c7fa269e4 was under development. Let's return to the behavior we've had since 2015: always act on extensions.* settings, regardless of repository format version. While we're here, include some tests to describe the effect on the "upgrade repository version" code path. [*] https://github.com/google/copybara/commit/ca76c0b1e13c4e36448d12c2aba4a5d9d98fb6e7 Reported-by: Johannes Schindelin Signed-off-by: Jonathan Nieder Signed-off-by: Junio C Hamano

Merge branch 'bc/sha-256-part-2'

2020-07-07T05:09:13Z

SHA-256 migration work continues. * bc/sha-256-part-2: (44 commits) remote-testgit: adapt for object-format bundle: detect hash algorithm when reading refs t5300: pass --object-format to git index-pack t5704: send object-format capability with SHA-256 t5703: use object-format serve option t5702: offer an object-format capability in the test t/helper: initialize the repository for test-sha1-array remote-curl: avoid truncating refs with ls-remote t1050: pass algorithm to index-pack when outside repo builtin/index-pack: add option to specify hash algorithm remote-curl: detect algorithm for dumb HTTP by size builtin/ls-remote: initialize repository based on fetch t5500: make hash independent serve: advertise object-format capability for protocol v2 connect: parse v2 refs with correct hash algorithm connect: pass full packet reader when parsing v2 refs Documentation/technical: document object-format for protocol v2 t1302: expect repo format version 1 for SHA-256 builtin/show-index: provide options to determine hash algo t5302: modernize test formatting ...

check_repository_format_gently(): refuse extensions for old repositories

2020-06-05T17:13:30Z

Previously, extensions were recognized regardless of repository format version. If the user sets an undefined "extensions" value on a repository of version 0 and that value is used by a future git version, they might get an undesired result. Because all extensions now also upgrade repository versions, tightening the check would help avoid this for future extensions. Signed-off-by: Xin Li Signed-off-by: Junio C Hamano

repository: add a helper function to perform repository format upgrade

2020-06-05T17:13:30Z

In version 1 of repository format, "extensions" gained special meaning and it is safer to avoid upgrading when there are pre-existing extensions. Make list-objects-filter to use the helper function instead of setting repository version directly as a prerequisite of exposing the upgrade capability. Signed-off-by: Xin Li Signed-off-by: Junio C Hamano

setup: set the_repository's hash algo when checking format

2020-05-27T17:07:06Z

When we're checking the repository's format, set the hash algorithm at the same time. This ensures that we perform a suitable initialization early enough to avoid confusing any parts of the code. If we defer until later, we can end up with portions of the code which are confused about the hash algorithm, resulting in segfaults when working with SHA-256 repositories. Signed-off-by: brian m. carlson Signed-off-by: Junio C Hamano

Merge branch 'bc/sha-256-part-1-of-4'

2020-03-27T00:11:20Z

SHA-256 transition continues. * bc/sha-256-part-1-of-4: (22 commits) fast-import: add options for rewriting submodules fast-import: add a generic function to iterate over marks fast-import: make find_marks work on any mark set fast-import: add helper function for inserting mark object entries fast-import: permit reading multiple marks files commit: use expected signature header for SHA-256 worktree: allow repository version 1 init-db: move writing repo version into a function builtin/init-db: add environment variable for new repo hash builtin/init-db: allow specifying hash algorithm on command line setup: allow check_repository_format to read repository format t/helper: make repository tests hash independent t/helper: initialize repository if necessary t/helper/test-dump-split-index: initialize git repository t6300: make hash algorithm independent t6300: abstract away SHA-1-specific constants t: use hash-specific lookup tables to define test constants repository: require a build flag to use SHA-256 hex: add functions to parse hex object IDs in any algorithm hex: introduce parsing variants taking hash algorithms ...

Merge branch 'am/real-path-fix'

2020-03-25T20:57:43Z

The real_path() convenience function can easily be misused; with a bit of code refactoring in the callers' side, its use has been eliminated. * am/real-path-fix: get_superproject_working_tree(): return strbuf real_path_if_valid(): remove unsafe API real_path: remove unsafe API set_git_dir: fix crash when used with real_path()

Merge branch 'es/outside-repo-errmsg-hints'

2020-03-16T19:43:29Z

An earlier update to show the location of working tree in the error message did not consider the possibility that a git command may be run in a bare repository, which has been corrected. * es/outside-repo-errmsg-hints: prefix_path: show gitdir if worktree unavailable