fix(clone): propagate object format in local clone by weihanglo · Pull Request #7226 · libgit2/libgit2

weihanglo · 2026-04-19T15:36:33Z

What is fixed in this PR

Local clone didn't propagate object format (sha2, sha256) from the source repo. In contrast, remote clone already did that

libgit2/src/libgit2/clone.c

Lines 448 to 450 in 1f34e2a

    
           if ((error = git_remote_oid_type(&oid_type, remote)) < 0 || 
        
               (error = git_repository__set_objectformat(repo, oid_type)) < 0) 
        
           	goto cleanup;

This PR follows suite.

A couple of tests are added

sha256_via_no_local
- file:// URL + GIT_CLONE_NO_LOCAL -> remote code path
sha256_object_format_is_propagated
- file:// URL + GIT_CLONE_LOCAL -> local code path with hardlinks
sha256_no_links_object_format_is_propagated
- file:// URL + GIT_CLONE_LOCAL_NO_LINKS -> local code path with copy

How to reviews

I run this command to run tests:

mkdir -p build && cd build
cmake .. -DGIT_EXPERIMENTAL_SHA256=ON -DBUILD_TESTS=ON
cmake --build .
./libgit2_tests -sclone::local

This PR is best reviewed commit by commit.

The first commit documents the problematic behavior, and can be served as minimal reproducer (you can checkout to the commit and confirm the buggy behavior exist).
The second commit contains the fix and the test assertion updates. The diff in test shows the behavior change.

Note

This issue was found during adding the sha256 to in Cargo with my current not-yet-merged integration in git2-rs: rust-lang/git2-rs#1206. Cargo leverages local clones a lot for git database caches.

It is quite hard for me to find every issues in a unstable-not-release PR. If we can get a new v1.9 release out it would help test out the sha256 feature :)

Not sure if I should open a PR against v1.9 branch though

Local clone, both hardlink and copy paths, does not propagate the source repository's object format to the destination. A SHA256 repository cloned locally is initialized as SHA1 and caused object lookup failures. These tests are added as reproducible examples, and will be fixed in the next commit * `sha256_via_no_local` * `file://` URL + `GIT_CLONE_NO_LOCAL` -> remote code path * `sha256_object_format_is_propagated` * `file://` URL + `GIT_CLONE_LOCAL` -> local code path with hardlinks * `sha256_no_links_object_format_is_propagated` * `file://` URL + `GIT_CLONE_LOCAL_NO_LINKS` -> local code path with copy

`clone_local_into()` copies objects from the source repository but does not set the destination's object format. This cause SHA256 repositories to be unreadable after a local clone because the destination defaults to SHA1. The remote clone path already handles this correctly so local clone path follows suite. See: <https://github.com/libgit2/libgit2/blob/1f34e2a57/src/libgit2/clone.c#L448-L450>

See libgit2/libgit2#7226

* libgit2/libgit2#7226 * libgit2/libgit2#7227

* libgit2/libgit2#7226 * libgit2/libgit2#7227 * libgit2/libgit2#7195

ethomson · 2026-04-23T20:22:38Z

Not sure if I should open a PR against v1.9 branch though

I will backport for a v1.9.x. Thanks!

Co-authored-by: Edward Thomson <ethomson@edwardthomson.com>

* libgit2/libgit2#7226 * libgit2/libgit2#7227 * libgit2/libgit2#7195

@kcsaul

v1.9.3 This release includes a number of bugfixes and compatibility improvements, particularly around SHA256 support. * cmake: fix linker error when using ninja build generator by @kcsaul in libgit2/libgit2#7249 * Handle redirects with Content-Length: 0 correctly by @ethomson in libgit2/libgit2#7246 * ci: use poxygit v0.8.1 in the tests by @ethomson in libgit2/libgit2#7248 * Zero indexer stats in pack objects by @ethomson in libgit2/libgit2#7243 * submodule: git_index_add_bypath does not move conflict entries to REUC by @lrm29 in libgit2/libgit2#7003 * fix: prevent SSH timeout infinite loop and enable TCP keepalive by @ambv in libgit2/libgit2#7165 * merge_files: avoid UB in xdiff by @ethomson in libgit2/libgit2#7239 * git_merge_file_from_index: handle cases when a child (ours or theirs) is null by @eantoranz in libgit2/libgit2#7092 * cmake: write git.h.tmp to current binary directory by @kcsaul in libgit2/libgit2#7241 * fix(pack): ensure pack_backend__read returns null terminated buffer by @kanru in libgit2/libgit2#7238 * Check object lengths against headers in read_loose by @howtonotwin in libgit2/libgit2#7178 * cmake: don't recreate git2.h unnecessarily by @ethomson in libgit2/libgit2#7234 * Memory Backend Corruption Fix by @kcsaul in libgit2/libgit2#7232 * Fixed a heap-buffer-overflow in the smart_pkt.c:set_data function by @oliverchang in libgit2/libgit2#7118 * fix(transport): get oid_type on local transport by @weihanglo in libgit2/libgit2#7229 * `GIT_REMOTE_DOWNLOAD_TAGS_ALL`: remove stray "the" in docs by @DanielEScherzer in libgit2/libgit2#7228 * fix(clone): propagate object format in local clone by @weihanglo in libgit2/libgit2#7226 * repo: Fix possible null pointer dereference by @csware in libgit2/libgit2#7225 * revparse: Allow `HEAD` abbreviation `@` by @KoviRobi in libgit2/libgit2#7218 * camke: include libssh2 in `Requires.private` in the PC file by @carlosmn in libgit2/libgit2#7215 * futils: fix undefined behavior in O_FSYNC fallback definition by @cehoffman in libgit2/libgit2#7211 * pcre: actually fix dangling-pointer warning by @ethomson in libgit2/libgit2#7206 * pcre: update cmake warnings for non-gcc by @ethomson in libgit2/libgit2#7205 * Fix some warnings with gcc by @ethomson in libgit2/libgit2#7203 * fix: apply insteadOf from global config for detached remotes by @weihanglo in libgit2/libgit2#7195 * Fix `git_index_entry` documentation by @bakersdozen123 in libgit2/libgit2#7192 * config: Fix potential null value passed to %s by @ethomson in libgit2/libgit2#7190 * index: support USE_NSEC=OFF by @ethomson in libgit2/libgit2#7187 * feat(remote): expose `git_remote_oid_type` by @weihanglo in libgit2/libgit2#7185 * fix(smart): keep caps across RPC stream resets by @weihanglo in libgit2/libgit2#7183 * fix wrong comment by @Murmele in libgit2/libgit2#7181 * fix(sha256): pass correct oid type by @weihanglo in libgit2/libgit2#7179 * examples: correct `git_commit_time` comment by @qaqland in libgit2/libgit2#7175 * tests: update to latest clar by @ethomson in libgit2/libgit2#7173 * delta: fix undefined behavior in hdr_sz varint parsing by @Oblivionsage in libgit2/libgit2#7172 * ci: Update macos-13 to macos-14 images on GitHub Actions by @ambv in libgit2/libgit2#7167 * ci: Fix cases of -Werror=discarded-qualifiers raised by @gcc 15.2 by @ambv in libgit2/libgit2#7164 * Use CMAKE_INSTALL_INCLUDEDIR for libgit2package INSTALL_INTERFACE by @aware70 in libgit2/libgit2#7155 * Fix C4703 uninitialized pointer variable warnings by @ShiningMassXAcc in libgit2/libgit2#7154 * test: check the correct filesystem for case-sensitivity by @ambv in libgit2/libgit2#7153 * ci: update ci/docker/fedora to work with Rawhide 44 by @ambv in libgit2/libgit2#7152 * refs: honor REFSPEC_SHORTHAND for multi-segment refs by @roberth in libgit2/libgit2#7148 * config: Fix potential null value passed to %s by @orgads in libgit2/libgit2#7131 * Fix potential access to uninitialized variables by @orgads in libgit2/libgit2#7130 * refspec: Detect DEL character in is_valid_name by @xokdvium in libgit2/libgit2#7120 * Update documentation to clarify that cert cb is always called by @ehuss in libgit2/libgit2#7119 * Update `racy.c` reference by @emmanuel-ferdman in libgit2/libgit2#7091 * Avoid duplicate definition of git_http_auth_dummy. by @JohannesWilde in libgit2/libgit2#7077

@kcsaul

v1.9.3 This release includes a number of bugfixes and compatibility improvements, particularly around SHA256 support. * cmake: fix linker error when using ninja build generator by @kcsaul in libgit2/libgit2#7249 * Handle redirects with Content-Length: 0 correctly by @ethomson in libgit2/libgit2#7246 * ci: use poxygit v0.8.1 in the tests by @ethomson in libgit2/libgit2#7248 * Zero indexer stats in pack objects by @ethomson in libgit2/libgit2#7243 * submodule: git_index_add_bypath does not move conflict entries to REUC by @lrm29 in libgit2/libgit2#7003 * fix: prevent SSH timeout infinite loop and enable TCP keepalive by @ambv in libgit2/libgit2#7165 * merge_files: avoid UB in xdiff by @ethomson in libgit2/libgit2#7239 * git_merge_file_from_index: handle cases when a child (ours or theirs) is null by @eantoranz in libgit2/libgit2#7092 * cmake: write git.h.tmp to current binary directory by @kcsaul in libgit2/libgit2#7241 * fix(pack): ensure pack_backend__read returns null terminated buffer by @kanru in libgit2/libgit2#7238 * Check object lengths against headers in read_loose by @howtonotwin in libgit2/libgit2#7178 * cmake: don't recreate git2.h unnecessarily by @ethomson in libgit2/libgit2#7234 * Memory Backend Corruption Fix by @kcsaul in libgit2/libgit2#7232 * Fixed a heap-buffer-overflow in the smart_pkt.c:set_data function by @oliverchang in libgit2/libgit2#7118 * fix(transport): get oid_type on local transport by @weihanglo in libgit2/libgit2#7229 * `GIT_REMOTE_DOWNLOAD_TAGS_ALL`: remove stray "the" in docs by @DanielEScherzer in libgit2/libgit2#7228 * fix(clone): propagate object format in local clone by @weihanglo in libgit2/libgit2#7226 * repo: Fix possible null pointer dereference by @csware in libgit2/libgit2#7225 * revparse: Allow `HEAD` abbreviation `@` by @KoviRobi in libgit2/libgit2#7218 * camke: include libssh2 in `Requires.private` in the PC file by @carlosmn in libgit2/libgit2#7215 * futils: fix undefined behavior in O_FSYNC fallback definition by @cehoffman in libgit2/libgit2#7211 * pcre: actually fix dangling-pointer warning by @ethomson in libgit2/libgit2#7206 * pcre: update cmake warnings for non-gcc by @ethomson in libgit2/libgit2#7205 * Fix some warnings with gcc by @ethomson in libgit2/libgit2#7203 * fix: apply insteadOf from global config for detached remotes by @weihanglo in libgit2/libgit2#7195 * Fix `git_index_entry` documentation by @bakersdozen123 in libgit2/libgit2#7192 * config: Fix potential null value passed to %s by @ethomson in libgit2/libgit2#7190 * index: support USE_NSEC=OFF by @ethomson in libgit2/libgit2#7187 * feat(remote): expose `git_remote_oid_type` by @weihanglo in libgit2/libgit2#7185 * fix(smart): keep caps across RPC stream resets by @weihanglo in libgit2/libgit2#7183 * fix wrong comment by @Murmele in libgit2/libgit2#7181 * fix(sha256): pass correct oid type by @weihanglo in libgit2/libgit2#7179 * examples: correct `git_commit_time` comment by @qaqland in libgit2/libgit2#7175 * tests: update to latest clar by @ethomson in libgit2/libgit2#7173 * delta: fix undefined behavior in hdr_sz varint parsing by @Oblivionsage in libgit2/libgit2#7172 * ci: Update macos-13 to macos-14 images on GitHub Actions by @ambv in libgit2/libgit2#7167 * ci: Fix cases of -Werror=discarded-qualifiers raised by @gcc 15.2 by @ambv in libgit2/libgit2#7164 * Use CMAKE_INSTALL_INCLUDEDIR for libgit2package INSTALL_INTERFACE by @aware70 in libgit2/libgit2#7155 * Fix C4703 uninitialized pointer variable warnings by @ShiningMassXAcc in libgit2/libgit2#7154 * test: check the correct filesystem for case-sensitivity by @ambv in libgit2/libgit2#7153 * ci: update ci/docker/fedora to work with Rawhide 44 by @ambv in libgit2/libgit2#7152 * refs: honor REFSPEC_SHORTHAND for multi-segment refs by @roberth in libgit2/libgit2#7148 * config: Fix potential null value passed to %s by @orgads in libgit2/libgit2#7131 * Fix potential access to uninitialized variables by @orgads in libgit2/libgit2#7130 * refspec: Detect DEL character in is_valid_name by @xokdvium in libgit2/libgit2#7120 * Update documentation to clarify that cert cb is always called by @ehuss in libgit2/libgit2#7119 * Update `racy.c` reference by @emmanuel-ferdman in libgit2/libgit2#7091 * Avoid duplicate definition of git_http_auth_dummy. by @JohannesWilde in libgit2/libgit2#7077

weihanglo added 2 commits April 19, 2026 11:34

This was referenced Apr 19, 2026

SHA-256 rust-lang/git2-rs#1090

Open

Support SHA256 Git repositories rust-lang/cargo#14942

Open

weihanglo added a commit to weihanglo/git2-rs that referenced this pull request Apr 19, 2026

chore(sys): update to commit with local clone fix

09fe1a4

See libgit2/libgit2#7226

weihanglo added a commit to weihanglo/git2-rs that referenced this pull request Apr 21, 2026

chore(sys): update to commit with local clone fix

bfc2b1e

See libgit2/libgit2#7226

weihanglo added a commit to weihanglo/git2-rs that referenced this pull request Apr 22, 2026

chore(sys): update to commit with local clone fix

8a66ce9

See libgit2/libgit2#7226

weihanglo added a commit to weihanglo/git2-rs that referenced this pull request Apr 22, 2026

chore(sys): update to commit with local clone fix

7220f89

See libgit2/libgit2#7226

weihanglo added a commit to weihanglo/git2-rs that referenced this pull request Apr 22, 2026

chore(sys): update to commit with local clone fix

a8a0dd1

See libgit2/libgit2#7226

weihanglo added a commit to weihanglo/git2-rs that referenced this pull request Apr 22, 2026

chore(sys): update libgit2 with sha256 fixes

6bdff23

* libgit2/libgit2#7226 * libgit2/libgit2#7227

weihanglo added a commit to weihanglo/git2-rs that referenced this pull request Apr 22, 2026

chore(sys): update libgit2 with sha256 fixes

980be12

* libgit2/libgit2#7226 * libgit2/libgit2#7227 * libgit2/libgit2#7195

ethomson reviewed Apr 23, 2026

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Co-authored-by: Edward Thomson <ethomson@edwardthomson.com>

ethomson merged commit d35f378 into libgit2:main Apr 23, 2026
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weihanglo deleted the local-object-format branch April 23, 2026 21:16

weihanglo added a commit to weihanglo/git2-rs that referenced this pull request Apr 23, 2026

chore(sys): update libgit2 with sha256 fixes

c30842b

* libgit2/libgit2#7226 * libgit2/libgit2#7227 * libgit2/libgit2#7195

ethomson added the v1.9.3 label Apr 29, 2026

BrewTestBot mentioned this pull request May 4, 2026

libgit2 1.9.3 Homebrew/homebrew-core#280887

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fix(clone): propagate object format in local clone#7226

fix(clone): propagate object format in local clone#7226
ethomson merged 3 commits into
libgit2:mainfrom
weihanglo:local-object-format

weihanglo commented Apr 19, 2026

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ethomson commented Apr 23, 2026

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	if ((error = git_remote_oid_type(&oid_type, remote)) < 0 \|\|
	(error = git_repository__set_objectformat(repo, oid_type)) < 0)
	goto cleanup;

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weihanglo commented Apr 19, 2026

What is fixed in this PR

How to reviews

Note

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ethomson commented Apr 23, 2026

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