Merge branch 'km/empty-repo-is-still-a-repo'

Running "git add" on a repository created inside the current
repository is an explicit indication that the user wants to add it
as a submodule, but when the HEAD of the inner repository is on an
unborn branch, it cannot be added as a submodule.  Worse, the files
in its working tree can be added as if they are a part of the outer
repository, which is not what the user wants.  These problems are
being addressed.

* km/empty-repo-is-still-a-repo:
  add: error appropriately on repository with no commits
  dir: do not traverse repositories with no commits
  submodule: refuse to add repository with no commits

builtin/add.c

@@ -374,11 +374,12 @@ static int add_files(struct dir_struct *dir, int flags)
 	}
 
 	for (i = 0; i < dir->nr; i++) {
-		check_embedded_repo(dir->entries[i]->name);
 		if (add_file_to_index(&the_index, dir->entries[i]->name, flags)) {
 			if (!ignore_add_errors)
 				die(_("adding files failed"));
 			exit_status = 1;
+		} else {
+			check_embedded_repo(dir->entries[i]->name);
 		}
 	}
 	return exit_status;

dir.c

@@ -1466,9 +1466,11 @@ static enum path_treatment treat_directory(struct dir_struct *dir,
 			return path_none;
 		}
 		if (!(dir->flags & DIR_NO_GITLINKS)) {
-			struct object_id oid;
-			if (resolve_gitlink_ref(dirname, "HEAD", &oid) == 0)
+			struct strbuf sb = STRBUF_INIT;
+			strbuf_addstr(&sb, dirname);
+			if (is_nonbare_repository_dir(&sb))
 				return exclude ? path_excluded : path_untracked;
+			strbuf_release(&sb);
 		}
 		return path_recurse;
 	}

git-submodule.sh

@@ -232,6 +232,13 @@ cmd_add()
 		die "$(eval_gettext "'\$sm_path' already exists in the index and is not a submodule")"
 	fi
 
+	if test -d "$sm_path" &&
+		test -z $(git -C "$sm_path" rev-parse --show-cdup 2>/dev/null)
+	then
+	    git -C "$sm_path" rev-parse --verify -q HEAD >/dev/null ||
+	    die "$(eval_gettext "'\$sm_path' does not have a commit checked out")"
+	fi
+
 	if test -z "$force" &&
 		! git add --dry-run --ignore-missing --no-warn-embedded-repo "$sm_path" > /dev/null 2>&1
 	then

read-cache.c

@@ -709,6 +709,7 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
 	int add_option = (ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE|
 			  (intent_only ? ADD_CACHE_NEW_ONLY : 0));
 	int hash_flags = HASH_WRITE_OBJECT;
+	struct object_id oid;
 
 	if (flags & ADD_CACHE_RENORMALIZE)
 		hash_flags |= HASH_RENORMALIZE;
@@ -718,6 +719,8 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
 
 	namelen = strlen(path);
 	if (S_ISDIR(st_mode)) {
+		if (resolve_gitlink_ref(path, "HEAD", &oid) < 0)
+			return error(_("'%s' does not have a commit checked out"), path);
 		while (namelen && path[namelen-1] == '/')
 			namelen--;
 	}

t/t3009-ls-files-others-nonsubmodule.sh

@@ -0,0 +1,50 @@
+#!/bin/sh
+
+test_description='test git ls-files --others with non-submodule repositories
+
+This test runs git ls-files --others with the following working tree:
+
+    nonrepo-no-files/
+      plain directory with no files
+    nonrepo-untracked-file/
+      plain directory with an untracked file
+    repo-no-commit-no-files/
+      git repository without a commit or a file
+    repo-no-commit-untracked-file/
+      git repository without a commit but with an untracked file
+    repo-with-commit-no-files/
+      git repository with a commit and no untracked files
+    repo-with-commit-untracked-file/
+      git repository with a commit and an untracked file
+'
+
+. ./test-lib.sh
+
+test_expect_success 'setup: directories' '
+	mkdir nonrepo-no-files/ &&
+	mkdir nonrepo-untracked-file &&
+	: >nonrepo-untracked-file/untracked &&
+	git init repo-no-commit-no-files &&
+	git init repo-no-commit-untracked-file &&
+	: >repo-no-commit-untracked-file/untracked &&
+	git init repo-with-commit-no-files &&
+	git -C repo-with-commit-no-files commit --allow-empty -mmsg &&
+	git init repo-with-commit-untracked-file &&
+	test_commit -C repo-with-commit-untracked-file msg &&
+	: >repo-with-commit-untracked-file/untracked
+'
+
+test_expect_success 'ls-files --others handles untracked git repositories' '
+	git ls-files -o >output &&
+	cat >expect <<-EOF &&
+	nonrepo-untracked-file/untracked
+	output
+	repo-no-commit-no-files/
+	repo-no-commit-untracked-file/
+	repo-with-commit-no-files/
+	repo-with-commit-untracked-file/
+	EOF
+	test_cmp expect output
+'
+
+test_done

t/t3700-add.sh

@@ -296,6 +296,17 @@ test_expect_success '"git add ." in empty repo' '
 	)
 '
 
+test_expect_success 'error on a repository with no commits' '
+	rm -fr empty &&
+	git init empty &&
+	test_must_fail git add empty >actual 2>&1 &&
+	cat >expect <<-EOF &&
+	error: '"'empty/'"' does not have a commit checked out
+	fatal: adding files failed
+	EOF
+	test_i18ncmp expect actual
+'
+
 test_expect_success 'git add --dry-run of existing changed file' "
 	echo new >>track-this &&
 	git add --dry-run track-this >actual 2>&1 &&
@@ -396,6 +407,7 @@ test_expect_success 'no file status change if no pathspec is given in subdir' '
 '
 
 test_expect_success 'all statuses changed in folder if . is given' '
+	rm -fr empty &&
 	git add --chmod=+x . &&
 	test $(git ls-files --stage | grep ^100644 | wc -l) -eq 0 &&
 	git add --chmod=-x . &&

t/t7400-submodule-basic.sh

@@ -46,6 +46,15 @@ test_expect_success 'submodule update aborts on missing gitmodules url' '
 	test_must_fail git submodule init
 '
 
+test_expect_success 'add aborts on repository with no commits' '
+	cat >expect <<-\EOF &&
+	'"'repo-no-commits'"' does not have a commit checked out
+	EOF
+	git init repo-no-commits &&
+	test_must_fail git submodule add ../a ./repo-no-commits 2>actual &&
+	test_i18ncmp expect actual
+'
+
 test_expect_success 'setup - repository in init subdirectory' '
 	mkdir init &&
 	(
@@ -809,7 +818,7 @@ test_expect_success '../bar/a/b/c works with relative local path - ../foo/bar.gi
 		cp pristine-.git-config .git/config &&
 		cp pristine-.gitmodules .gitmodules &&
 		mkdir -p a/b/c &&
-		(cd a/b/c && git init) &&
+		(cd a/b/c && git init && test_commit msg) &&
 		git config remote.origin.url ../foo/bar.git &&
 		git submodule add ../bar/a/b/c ./a/b/c &&
 		git submodule init &&