builtin/: add UNLEAKs

Add some UNLEAKs where we are about to return from `cmd_*`. UNLEAK the
variables in the same order as we've declared them. While addressing
`msg` in builtin/tag.c, convert the existing `strbuf_release()` calls as
well.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/checkout.c

@@ -1291,6 +1291,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
 		strbuf_release(&buf);
 	}
 
+	UNLEAK(opts);
 	if (opts.patch_mode || opts.pathspec.nr)
 		return checkout_paths(&opts, new.name);
 	else

builtin/diff-index.c

@@ -57,5 +57,6 @@ int cmd_diff_index(int argc, const char **argv, const char *prefix)
 		return -1;
 	}
 	result = run_diff_index(&rev, cached);
+	UNLEAK(rev);
 	return diff_result_code(&rev.diffopt, result);
 }

builtin/diff.c

@@ -466,5 +466,8 @@ int cmd_diff(int argc, const char **argv, const char *prefix)
 	result = diff_result_code(&rev.diffopt, result);
 	if (1 < rev.diffopt.skip_stat_unmatch)
 		refresh_index_quietly();
+	UNLEAK(rev);
+	UNLEAK(ent);
+	UNLEAK(blob);
 	return result;
 }

builtin/name-rev.c

@@ -494,5 +494,6 @@ int cmd_name_rev(int argc, const char **argv, const char *prefix)
 				  always, allow_undefined, data.name_only);
 	}
 
+	UNLEAK(revs);
 	return 0;
 }

builtin/tag.c

@@ -552,9 +552,10 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	if (force && !is_null_oid(&prev) && oidcmp(&prev, &object))
 		printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev.hash, DEFAULT_ABBREV));
 
-	strbuf_release(&err);
-	strbuf_release(&buf);
-	strbuf_release(&ref);
-	strbuf_release(&reflog_msg);
+	UNLEAK(buf);
+	UNLEAK(ref);
+	UNLEAK(reflog_msg);
+	UNLEAK(msg);
+	UNLEAK(err);
 	return 0;
 }