| Message ID | 39e56dab621a2a1e0cbaf67f8de44614c354dcb1.1713519789.git.ps@pks.im (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Stop relying on SHA1 fallback for `the_hash_algo` | expand |
Patrick Steinhardt <ps@pks.im> writes: > The git-diff(1) command can be used outside repositories to diff two > files with each other. But even if there is no repository we will end up > hashing the files that we are diffing so that we can print the "index" > line: > > ``` > diff --git a/a b/b > index 7898192..6178079 100644 > --- a/a > +++ b/b > @@ -1 +1 @@ > -a > +b > ``` This will break "git am"; it is customary to indent such sample patch block in a log message. > We implicitly use SHA1 to calculate the hash here, which is because > `the_repository` gets initialized with SHA1 during the startup routine. > We are about to stop doing this though such that `the_repository` only > ever has a hash function when it was properly initialized via a repo's > configuration. > > To give full control to our users, we would ideally add a new switch to > git-diff(1) that allows them to specify the hash function when executed > outside of a repository. But for now, we only convert the code to make > this explicit such that we can stop setting the default hash algorithm > for `the_repository`. > > Signed-off-by: Patrick Steinhardt <ps@pks.im> > --- > builtin/diff.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/builtin/diff.c b/builtin/diff.c > index 6e196e0c7d..58ec7e5da2 100644 > --- a/builtin/diff.c > +++ b/builtin/diff.c > @@ -465,6 +465,15 @@ int cmd_diff(int argc, const char **argv, const char *prefix) > no_index = DIFF_NO_INDEX_IMPLICIT; > } > > + /* > + * When operating outside of a Git repository we need to have a hash > + * algorithm at hand so that we can generate the blob hashes. We > + * default to SHA1 here, but may eventually want to change this to be > + * configurable via a command line option. > + */ > + if (nongit) > + repo_set_hash_algo(the_repository, GIT_HASH_SHA1); > + > init_diff_ui_defaults(); > git_config(git_diff_ui_config, NULL); > prefix = precompose_argv_prefix(argc, argv, prefix);
diff --git a/a b/b index 7898192..6178079 100644 --- a/a +++ b/b @@ -1 +1 @@ -a +b ``` We implicitly use SHA1 to calculate the hash here, which is because `the_repository` gets initialized with SHA1 during the startup routine. We are about to stop doing this though such that `the_repository` only ever has a hash function when it was properly initialized via a repo's configuration. To give full control to our users, we would ideally add a new switch to git-diff(1) that allows them to specify the hash function when executed outside of a repository. But for now, we only convert the code to make this explicit such that we can stop setting the default hash algorithm for `the_repository`. Signed-off-by: Patrick Steinhardt <ps@pks.im> --- builtin/diff.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/builtin/diff.c b/builtin/diff.c index 6e196e0c7d..58ec7e5da2 100644 --- a/builtin/diff.c +++ b/builtin/diff.c @@ -465,6 +465,15 @@ int cmd_diff(int argc, const char **argv, const char *prefix) no_index = DIFF_NO_INDEX_IMPLICIT; } + /* + * When operating outside of a Git repository we need to have a hash + * algorithm at hand so that we can generate the blob hashes. We + * default to SHA1 here, but may eventually want to change this to be + * configurable via a command line option. + */ + if (nongit) + repo_set_hash_algo(the_repository, GIT_HASH_SHA1); + init_diff_ui_defaults(); git_config(git_diff_ui_config, NULL); prefix = precompose_argv_prefix(argc, argv, prefix);