From: Shreyansh Paliwal Date: Fri, 30 Jan 2026 15:31:23 +0000 (+0530) Subject: show-index: warn when falling back to SHA-1 outside a repository X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ea39808a22714b8f61b9472de7ef467ced15efea;p=thirdparty%2Fgit.git show-index: warn when falling back to SHA-1 outside a repository When 'git show-index' is run outside of a repository and no hashing algorithm is specified via --object-format, it silently falls back to SHA-1, relying on the historical default. This works for existing SHA-1 based index files, but the behavior can be ambiguous and confusing when the input index file uses a different hash algorithm, such as SHA-256. Add a warning when this fallback happens to make the assumption explicit and to guide users toward using --object-format when needed. Signed-off-by: Shreyansh Paliwal Signed-off-by: Junio C Hamano --- diff --git a/builtin/show-index.c b/builtin/show-index.c index 2c3e2940ce..45795da2da 100644 --- a/builtin/show-index.c +++ b/builtin/show-index.c @@ -43,11 +43,14 @@ int cmd_show_index(int argc, /* * Fallback to SHA1 if we are running outside of a repository. * - * TODO: Figure out and implement a way to detect the hash algorithm in use by the - * the index file passed in and use that instead. + * TODO: If a future implementation of index file version encodes the hash + * algorithm in its header, enable show-index to infer it from the + * header rather than relying on repository context or a default fallback. */ - if (!the_hash_algo) + if (!the_hash_algo) { + warning(_("assuming SHA-1; use --object-format to override")); repo_set_hash_algo(the_repository, GIT_HASH_DEFAULT); + } hashsz = the_hash_algo->rawsz;