On Mon, Sep 08, 2008 at 09:24:39AM -0400, Eric Gerlach wrote:
> The case I'm looking to protect against is the following:
>
> $ mkdir -p new-repo/debian
> $ cd new-repo
> $ git init
> $ vi debian/changelog (add a few lines)
> $ git add debian/changelog
> $ debcommit
>
> (which runs
> $ git diff --cached debian/changelog)
>
> If I can test before the git-diff, then I can run "diff debian/changelog
> /dev/null" instead of the git-diff and all is well.
In that case, I would use the "rev-parse --verify HEAD" I mentioned,
since it exactly covers the situation you are trying to avoid. What you
are saying is something like:
if there is a previous commit on the current branch
diff against previous commit on the current branch
else
diff against /dev/null
So your "show-ref" attempt could actually say "yes, the repo is
non-empty" but your diff would still fail (because the commits just
weren't on the current branch).
As an aside, it's too bad "--root" isn't more widely supported. Then
git diff --root --cached
would do what you want without the need for any conditionals. But it
seems that --root only works between trees. Something like the patch
below would help, but I'm sure this is covering only one of many cases.
---
diff --git a/builtin-diff.c b/builtin-diff.c
index 52470c7..43db970 100644
--- a/builtin-diff.c
+++ b/builtin-diff.c
@@ -317,8 +317,11 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
break;
else if (!strcmp(arg, "--cached")) {
add_head_to_pending(&rev);
- if (!rev.pending.nr)
- die("No HEAD commit to compare with (yet)");
+ if (!rev.pending.nr) {
+ if (!rev.show_root_diff)
+ die("No HEAD commit to compare with (yet)");
+ add_empty_to_pending(&rev);
+ }
break;
}
}
diff --git a/revision.c b/revision.c
index 2f646de..7ec3990 100644
--- a/revision.c
+++ b/revision.c
@@ -145,16 +145,27 @@ void add_pending_object(struct rev_info *revs, struct object *obj, const char *n
add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
}
-void add_head_to_pending(struct rev_info *revs)
+static void add_to_pending_by_name(struct rev_info *revs, const char *name)
{
unsigned char sha1[20];
struct object *obj;
- if (get_sha1("HEAD", sha1))
+ if (get_sha1(name, sha1))
return;
obj = parse_object(sha1);
if (!obj)
return;
- add_pending_object(revs, obj, "HEAD");
+ add_pending_object(revs, obj, name);
+}
+
+void add_head_to_pending(struct rev_info *revs)
+{
+ add_to_pending_by_name(revs, "HEAD");
+}
+
+void add_empty_to_pending(struct rev_info *revs)
+{
+ add_to_pending_by_name(revs,
+ "4b825dc642cb6eb9a060e54bf8d69288fbee4904");
}
static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
diff --git a/revision.h b/revision.h
index 2fdb2dd..8c990d5 100644
--- a/revision.h
+++ b/revision.h
@@ -152,6 +152,7 @@ extern void add_object(struct object *obj,
extern void add_pending_object(struct rev_info *revs, struct object *obj, const char *name);
extern void add_head_to_pending(struct rev_info *);
+extern void add_empty_to_pending(struct rev_info *);
enum commit_action {
commit_ignore,
--
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