On Fri, Jan 11, 2019 at 09:51:06AM -0500, Jeff King wrote:
> I think rewrite_here needs to be a direct pointer into the buffer, since
> we plan to modify it.
>
> I think rewrite_with is correct to be an object_id. It's either the oid
> passed in from the caller, or the subtree we generated (in which case
> it's the result from write_object_file).
>
> So the "most correct" thing is probably something like this:
Of course, it would be nice if what I sent compiled. ;)
rewrite_here does double duty: it's the pointer in the tree that we need
to rewrite, and it's also the oid we pass down recursively. So we have
to handle both cases, like so:
diff --git a/match-trees.c b/match-trees.c
index 03e81b56e1..3e0ed889b4 100644
--- a/match-trees.c
+++ b/match-trees.c
@@ -179,7 +179,7 @@ static int splice_tree(const struct object_id *oid1, const char *prefix,
char *buf;
unsigned long sz;
struct tree_desc desc;
- struct object_id *rewrite_here;
+ unsigned char *rewrite_here;
const struct object_id *rewrite_with;
struct object_id subtree;
enum object_type type;
@@ -206,9 +206,16 @@ static int splice_tree(const struct object_id *oid1, const char *prefix,
if (!S_ISDIR(mode))
die("entry %s in tree %s is not a tree", name,
oid_to_hex(oid1));
- rewrite_here = (struct object_id *)(desc.entry.path +
- strlen(desc.entry.path) +
- 1);
+ /*
+ * We cast here for two reasons:
+ *
+ * - to flip the "char *" (for the path) to "unsigned
+ * char *" (for the hash stored after it)
+ *
+ * - to discard the "const"; this is OK because we
+ * know it points into our non-const "buf"
+ */
+ rewrite_here = (unsigned char *)desc.entry.path + strlen(desc.entry.path) + 1;
break;
}
update_tree_entry(&desc);
@@ -217,14 +224,16 @@ static int splice_tree(const struct object_id *oid1, const char *prefix,
die("entry %.*s not found in tree %s", toplen, prefix,
oid_to_hex(oid1));
if (*subpath) {
- status = splice_tree(rewrite_here, subpath, oid2, &subtree);
+ struct object_id tree_oid;
+ hashcpy(tree_oid.hash, rewrite_here);
+ status = splice_tree(&tree_oid, subpath, oid2, &subtree);
if (status)
return status;
rewrite_with = &subtree;
} else {
rewrite_with = oid2;
}
- hashcpy(rewrite_here->hash, rewrite_with->hash);
+ hashcpy(rewrite_here, rewrite_with->hash);
status = write_object_file(buf, sz, tree_type, result);
free(buf);
return status;
