Currently, - Running "index-pack --promisor" outside a repo segfaults. - It may be confusing to a user that running "index-pack --promisor" within a repo may make changes to the repo's object DB, especially since the packs indexed by the index-pack invocation may not even be related to the repo. As discussed in [1] and [2], teaching --promisor to forbid a packfile name solves both these problems. This combination of arguments requires a repo (since we are writing the resulting .pack and .idx to it) and it is clear that the files are related to the repo. Currently, Git uses "index-pack --promisor" only when fetching into a repo, so it could be argued that we should teach "index-pack" a new argument (say, "--fetching-mode") instead of tying --promisor to a generic argument like the packfile name. However, this --promisor feature could conceivably be used whenever we have a packfile that is known to come from the promisor remote (whether obtained through Git's fetch protocol or through other means) so not using a new argument seems reasonable - one could envision a user-made script obtaining a packfile and then running "index-pack --promisor --stdin", for example. In fact, it might be possible to relax the restriction further (say, by also allowing --promisor when indexing a packfile that is in the object DB), but relaxing the restriction is backwards-compatible so we can revisit that later. One thing to watch out for is the possibility of a future Git feature that indexes a pack in the context of a repo, but does not necessarily write the resulting pack to it (and does not necessarily desire to make any changes to the object DB). One such feature would be fetch quarantine, which might need the repo context in order to detect hash collisions, but would also need to ensure that the object DB is undisturbed in case the fetch fails for whatever reason, even if the reason occurs only after the indexing is complete. It may not be obvious to the implementer of such a feature that "index-pack" could sometimes write packs other than the indexed pack to the object DB, but there are already other ways that "fetch" could write to the object DB (in particular, packfile URIs and bundle URIs), so hopefully the implementation of this future feature would already include a test that the object DB be undisturbed. This change requires the change to t5300 by 1f52cdfacb (index-pack: document and test the --promisor option, 2022-03-09) to be undone. (--promisor is already tested indirectly, so we don't need the explicit test here any more.) [1] https://lore.kernel.org/git/20241114005652.GC1140565@xxxxxxxxxxxxxxxxxxxxxxx/ [2] https://lore.kernel.org/git/20241119185345.GB15723@xxxxxxxxxxxxxxxxxxxxxxx/ Signed-off-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx> --- This is on jt/repack-local-promisor. Thanks, Peff, for the catch. Here's an updated patch, with an updated commit message. --- Documentation/git-index-pack.txt | 2 ++ builtin/index-pack.c | 2 ++ t/t5300-pack-object.sh | 4 +--- 3 files changed, 5 insertions(+), 3 deletions(-) diff --git a/Documentation/git-index-pack.txt b/Documentation/git-index-pack.txt index 4be09e58e7..58dd5b5f0e 100644 --- a/Documentation/git-index-pack.txt +++ b/Documentation/git-index-pack.txt @@ -144,6 +144,8 @@ Also, if there are objects in the given pack that references non-promisor objects (in the repo), repacks those non-promisor objects into a promisor pack. This avoids a situation in which a repo has non-promisor objects that are accessible through promisor objects. ++ +Requires <pack-file> to not be specified. NOTES ----- diff --git a/builtin/index-pack.c b/builtin/index-pack.c index 08b340552f..05758a2f3e 100644 --- a/builtin/index-pack.c +++ b/builtin/index-pack.c @@ -1970,6 +1970,8 @@ int cmd_index_pack(int argc, usage(index_pack_usage); if (fix_thin_pack && !from_stdin) die(_("the option '%s' requires '%s'"), "--fix-thin", "--stdin"); + if (promisor_msg && pack_name) + die(_("--promisor cannot be used with a pack name")); if (from_stdin && !startup_info->have_repository) die(_("--stdin requires a git repository")); if (from_stdin && hash_algo) diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh index aff164ddf8..c53f355e48 100755 --- a/t/t5300-pack-object.sh +++ b/t/t5300-pack-object.sh @@ -332,10 +332,8 @@ test_expect_success 'build pack index for an existing pack' ' git index-pack -o tmp.idx test-3.pack && cmp tmp.idx test-1-${packname_1}.idx && - git index-pack --promisor=message test-3.pack && + git index-pack test-3.pack && cmp test-3.idx test-1-${packname_1}.idx && - echo message >expect && - test_cmp expect test-3.promisor && cat test-2-${packname_2}.pack >test-3.pack && git index-pack -o tmp.idx test-2-${packname_2}.pack && Range-diff against v1: 1: b5a0012531 ! 1: 226a627c25 index-pack: teach --promisor to require --stdin @@ Metadata Author: Jonathan Tan <jonathantanmy@xxxxxxxxxx> ## Commit message ## - index-pack: teach --promisor to require --stdin + index-pack: teach --promisor to forbid pack name Currently, @@ Commit message since the packs indexed by the index-pack invocation may not even be related to the repo. - As discussed in [1], teaching --promisor to require --stdin and forbid a - packfile name solves both these problems. This combination of arguments - requires a repo (since we are writing the resulting .pack and .idx to - it) and it is clear that the files are related to the repo. + As discussed in [1] and [2], teaching --promisor to forbid a packfile + name solves both these problems. This combination of arguments requires + a repo (since we are writing the resulting .pack and .idx to it) and it + is clear that the files are related to the repo. Currently, Git uses "index-pack --promisor" only when fetching into - a repo, so it could be argued that we should teach "index-pack" a new - argument (say, "--fetching-mode") instead of tying --promisor to a - generic argument like "--stdin". However, this --promisor feature could - conceivably be used whenever we have a packfile that is known to come - from the promisor remote (whether obtained through Git's fetch protocol - or through other means) so it seems reasonable to use --stdin here - - one could envision a user-made script obtaining a packfile and then - running "index-pack --promisor --stdin", for example. In fact, it might - be possible to relax the restriction further (say, by also allowing - --promisor when indexing a packfile that is in the object DB), but - relaxing the restriction is backwards-compatible so we can revisit that - later. + a repo, so it could be argued that we should teach "index-pack" a + new argument (say, "--fetching-mode") instead of tying --promisor to + a generic argument like the packfile name. However, this --promisor + feature could conceivably be used whenever we have a packfile that is + known to come from the promisor remote (whether obtained through Git's + fetch protocol or through other means) so not using a new argument seems + reasonable - one could envision a user-made script obtaining a packfile + and then running "index-pack --promisor --stdin", for example. In fact, + it might be possible to relax the restriction further (say, by also + allowing --promisor when indexing a packfile that is in the object DB), + but relaxing the restriction is backwards-compatible so we can revisit + that later. One thing to watch out for is the possibility of a future Git feature that indexes a pack in the context of a repo, but does not necessarily @@ Commit message test here any more.) [1] https://lore.kernel.org/git/20241114005652.GC1140565@xxxxxxxxxxxxxxxxxxxxxxx/ + [2] https://lore.kernel.org/git/20241119185345.GB15723@xxxxxxxxxxxxxxxxxxxxxxx/ Signed-off-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx> --- This is on jt/repack-local-promisor. - Looking into it further, I think that we also need to require no - packfile name to be given (so that we are writing the file to the - repository). Therefore, I've added that requirement both in the code and - in the documentation. - - I've tried to summarize our conversation in the commit message - if you - notice anything missing or incorrect, feel free to let me know. + Thanks, Peff, for the catch. Here's an updated patch, with an updated + commit message. ## Documentation/git-index-pack.txt ## @@ Documentation/git-index-pack.txt: Also, if there are objects in the given pack that references non-promisor @@ Documentation/git-index-pack.txt: Also, if there are objects in the given pack t pack. This avoids a situation in which a repo has non-promisor objects that are accessible through promisor objects. ++ -+Requires --stdin, and requires <pack-file> to not be specified. ++Requires <pack-file> to not be specified. NOTES ----- @@ builtin/index-pack.c: int cmd_index_pack(int argc, usage(index_pack_usage); if (fix_thin_pack && !from_stdin) die(_("the option '%s' requires '%s'"), "--fix-thin", "--stdin"); -+ if (promisor_msg && !from_stdin) -+ die(_("the option '%s' requires '%s'"), "--promisor", "--stdin"); + if (promisor_msg && pack_name) + die(_("--promisor cannot be used with a pack name")); if (from_stdin && !startup_info->have_repository) -- 2.47.0.338.g60cca15819-goog
