ls-files: support --recurse-submodules --stage

e77aa336f1 ("ls-files: optionally recurse into submodules", 2016-10-10)
taught ls-files the --recurse-submodules argument, but only in a limited
set of circumstances. In particular, --stage was unsupported, perhaps
because there was no repo_find_unique_abbrev(), which was only
introduced in 8bb95572b0 ("sha1-name.c: add
repo_find_unique_abbrev_r()", 2019-04-16). This function is needed for
using --recurse-submodules with --stage.

Now that we have repo_find_unique_abbrev(), teach support for this
combination of arguments.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-ls-files.txt

@@ -156,7 +156,7 @@ a space) at the start of each line:
 
 --recurse-submodules::
 	Recursively calls ls-files on each active submodule in the repository.
-	Currently there is only support for the --cached mode.
+	Currently there is only support for the --cached and --stage modes.
 
 --abbrev[=<n>]::
 	Instead of showing the full 40-byte hexadecimal object

builtin/ls-files.c

@@ -244,7 +244,7 @@ static void show_ce(struct repository *repo, struct dir_struct *dir,
 			printf("%s%06o %s %d\t",
 			       tag,
 			       ce->ce_mode,
-			       find_unique_abbrev(&ce->oid, abbrev),
+			       repo_find_unique_abbrev(repo, &ce->oid, abbrev),
 			       ce_stage(ce));
 		}
 		write_eolinfo(repo->index, ce, fullname);
@@ -726,7 +726,7 @@ int cmd_ls_files(int argc, const char **argv, const char *cmd_prefix)
 		setup_work_tree();
 
 	if (recurse_submodules &&
-	    (show_stage || show_deleted || show_others || show_unmerged ||
+	    (show_deleted || show_others || show_unmerged ||
 	     show_killed || show_modified || show_resolve_undo || with_tree))
 		die("ls-files --recurse-submodules unsupported mode");
 

t/t3007-ls-files-recurse-submodules.sh

@@ -34,6 +34,23 @@ test_expect_success 'ls-files correctly outputs files in submodule' '
 	test_cmp expect actual
 '
 
+test_expect_success '--stage' '
+	GITMODULES_HASH=$(git rev-parse HEAD:.gitmodules) &&
+	A_HASH=$(git rev-parse HEAD:a) &&
+	B_HASH=$(git rev-parse HEAD:b/b) &&
+	C_HASH=$(git -C submodule rev-parse HEAD:c) &&
+
+	cat >expect <<-EOF &&
+	100644 $GITMODULES_HASH 0	.gitmodules
+	100644 $A_HASH 0	a
+	100644 $B_HASH 0	b/b
+	100644 $C_HASH 0	submodule/c
+	EOF
+
+	git ls-files --stage --recurse-submodules >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'ls-files correctly outputs files in submodule with -z' '
 	lf_to_nul >expect <<-\EOF &&
 	.gitmodules
@@ -292,7 +309,6 @@ test_incompatible_with_recurse_submodules () {
 test_incompatible_with_recurse_submodules --deleted
 test_incompatible_with_recurse_submodules --modified
 test_incompatible_with_recurse_submodules --others
-test_incompatible_with_recurse_submodules --stage
 test_incompatible_with_recurse_submodules --killed
 test_incompatible_with_recurse_submodules --unmerged