Re: [PATCH] git-mv: Keep moved index entries inact

On Sat, Jul 19, 2008 at 04:54:20PM -0700, Junio C Hamano wrote:

Petr Baudis [off-list ref] writes:

quoted

diff --git a/read-cache.c b/read-cache.c
index 1648428..70e5f57 100644
--- a/read-cache.c
+++ b/read-cache.c

@@ -38,6 +38,21 @@ static void replace_index_entry(struct index_state *istate, int nr, struct cache
 	istate->cache_changed = 1;
 }
 
+void rename_index_entry_at(struct index_state *istate, int nr, const char *new_name)
+{
+	struct cache_entry *old = istate->cache[nr], *new;
+	int namelen = strlen(new_name);
+
+	new = xmalloc(cache_entry_size(namelen));
+	copy_cache_entry(new, old);
+	new->ce_flags = (new->ce_flags & ~CE_NAMEMASK) | namelen;
+	memcpy(new->name, new_name, namelen);
+
+	cache_tree_invalidate_path(istate->cache_tree, old->name);
+	remove_index_entry_at(istate, nr);
+	add_index_entry(istate, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
+}

Hmm, would this use of copy_cache_entry() kosher, I have to wonder.  This
new copy of cache entry begins its life unhashed, doesn't it?  Shouldn't
we be not copying its hashed/unhashed bits from the old one?

Also setting of that ce_flags looks wrong when namelen does not fit within
the width of CE_NAMEMASK.  Shouldn't it be doing the same thing as
create_ce_flags()?

I have to admit that I don't clearly understand all the index entry
intricacies. It is good you didn't see my earlier misguided attempts.
:-) I have patched the two mistakes you pointed out. It is too bad I
cannot simply use existing functions for this, but I want to keep a
different set of traits that either copy_cache_entry() or
create_ce_flags() assumes.

quoted

diff --git a/t/t7001-mv.sh b/t/t7001-mv.sh
index 336cfaa..6b615f8 100755
--- a/t/t7001-mv.sh
+++ b/t/t7001-mv.sh

@@ -156,4 +156,61 @@ test_expect_success 'absolute pathname outside should fail' '(
 
 )'
 
+# git mv meets angry Git maintainer

What's this comment about?

Oh. Well, you sounded agitated in your original mail, but this actually
just slipped through. :-)

quoted

+test_expect_success 'git mv should not change sha1 of moved cache entry' '
+
+	rm -fr .git &&
+	git init &&
+	echo 1 >dirty &&
+	git add dirty &&
+	entry="$(git ls-files --stage dirty | cut -f 1)"

"rev-parse :dirty"?

I want to make sure the whole index entry is intact, not just the sha1.

-- 
				Petr "Pasky" Baudis
As in certain cults it is possible to kill a process if you know
its true name.  -- Ken Thompson and Dennis M. Ritchie