Junio C Hamano  committed 2b86976

git-prune: never lose objects reachable from our refs.

Explicit <head> arguments to git-prune replaces, instead of
extends, the list of heads used for reachability analysis by
fsck-objects. By giving a subset of heads by mistake, objects
reachable only from other heads can be removed, resulting in a
corrupted repository.

This commit stops replacing the list of heads, and makes the
command line arguments to add to them instead for safety.

Signed-off-by: Junio C Hamano <>

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  • Parent commits 2dee581

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File Documentation/git-prune.txt

-This runs `git-fsck-objects --unreachable` using the heads
-specified on the command line (or `$GIT_DIR/refs/heads/\*` and
-`$GIT_DIR/refs/tags/\*` if none is specified), and prunes all
-unreachable objects from the object database.  In addition, it
+This runs `git-fsck-objects --unreachable` using all the refs
+available in `$GIT_DIR/refs`, optionally with additional set of
+objects specified on the command line, and prunes all
+objects unreachable from any of these head objects from the object database.
+In addition, it
 prunes the unpacked objects that are also found in packs by
 running `git prune-packed`.
 	Do not interpret any more arguments as options.
-	Instead of keeping objects
+	In addition to objects
 	reachable from any of our references, keep objects
-	reachable from only listed <head>s.
-Note that the explicitly named <head>s are *not* appended to the
-default set of references, but they replace them.  In general you
-would want to say `git prune $(git-rev-parse --all) extra1
-extra2` to keep chains of commits leading to extra1, extra2,
-... in addition to what are reachable from your own refs.
-Saying `git prune extra1 extra2` would *lose* objects reachable
-only from the usual refs, which is usually not what you want.
+	reachable from listed <head>s.
-To prune objects not used by your repository and another that
+To prune objects not used by your repository nor another that
 borrows from your repository via its
-$ git prune $(git-rev-parse --all) \
-  $(cd ../another && $(git-rev-parse --all))
+$ git prune $(cd ../another && $(git-rev-parse --all))


-git-fsck-objects --full --cache --unreachable "$@" |
+case "$#" in
+0) git-fsck-objects --full --cache --unreachable ;;
+*) git-fsck-objects --full --cache --unreachable $(git-rev-parse --all) "$@" ;;
+esac |
 sed -ne '/unreachable /{
     s/unreachable [^ ][^ ]* //