Re: [PATCH 6/9] rev-parse: allow printing compatibility hash

"brian m. carlson" [off-list ref] writes:

Right now, we have a way to print the storage hash, the input hash, and
the output hash, but we lack a way to print the compatibility hash.  Add
a new type to --show-object-format, compat, which prints this value.

If no compatibility hash exists, simply print a newline.  This is
important to allow users to use multiple options at once while still
getting unambiguous output.

Signed-off-by: brian m. carlson <redacted>
---

Nice.

At first I somehow thought 

    $ git rev-parse --show-object-format=compat HEAD

in a SHA-1 primary repository would give the equivalent object name
for the commit at HEAD in SHA-256 world, but that is expecting too
much out of a simple 50-line patch ;-).

 
 				if (strcmp(val, "storage") &&
+				    strcmp(val, "compat") &&
 				    strcmp(val, "input") &&
 				    strcmp(val, "output"))
 					die(_("unknown mode for --show-object-format: %s"),
 					    arg);
-				puts(the_hash_algo->name);
+
+				if (!strcmp(val, "compat")) {
+					if (the_repository->compat_hash_algo)
+						puts(the_repository->compat_hash_algo->name);
+					else
+						putchar('\n');
+				} else {
+					puts(the_hash_algo->name);
+				}
 				continue;
 			}
 			if (!strcmp(arg, "--show-ref-format")) {

Pretty straight-forward.

Thanks.