repack: expand error message for missing pack files

If pack-objects tells us it generated pack $hash, we expect to find
.tmp-$$-pack-$hash.pack, .idx, .rev, and so on. Some of these files are
optional, but others are not. For the required ones, we'll bail with an
error if any of them is missing.

The error message is just "missing required file", which is a bit vague.
We should be more clear that it is not the user's fault, but rather that
the sub-pgoram we called is not operating as expected. In practice,
nobody should ever see this message, as it would generally only be
caused by a bug in Git.

It probably doesn't make sense to convert this to a BUG(), though, as
there are other (unlikely) possibilities, such as somebody else racily
deleting the files, filesystem errors causing stat() to fail, and so on.

A nice side effect here is that we stop relying on fname_old in this
code path, which will let us deal with it only in the first part of the
conditional.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/repack.c b/builtin/repack.c
index b5bd9e5fedb3e79dd60ce030af1bd1fb2a99d85a..d1929bb3dbca9e9efb3f6af1919e7400c4490771 100644 (file)
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -1030,7 +1030,8 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
                                if (rename(fname_old, fname))
                                        die_errno(_("renaming '%s' failed"), fname_old);
                        } else if (!exts[ext].optional)
-                               die(_("missing required file: %s"), fname_old);
+                               die(_("pack-objects did not write a '%s' file for pack %s-%s"),
+                                   exts[ext].name, packtmp, item->string);
                        else if (unlink(fname) < 0 && errno != ENOENT)
                                die_errno(_("could not unlink: %s"), fname);