git submodule add: Require the new --force option to add ignored paths

To make the behavior of "git submodule add" more consistent with "git add"
ignored submodule paths should not be silently added when they match an
entry in a .gitignore file. To be able to override that default behavior
in the same way as we can do that for "git add", the new option "--force"
is introduced.

Signed-off-by: Jens Lehmann <Jens.Lehmann@web.de>
Acked-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-submodule.txt

@@ -9,7 +9,7 @@ git-submodule - Initialize, update or inspect submodules
 SYNOPSIS
 --------
 [verse]
-'git submodule' [--quiet] add [-b branch]
+'git submodule' [--quiet] add [-b branch] [-f|--force]
 	      [--reference <repository>] [--] <repository> [<path>]
 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...]
 'git submodule' [--quiet] init [--] [<path>...]
@@ -187,6 +187,11 @@ OPTIONS
 --branch::
 	Branch of repository to add as submodule.
 
+-f::
+--force::
+	This option is only valid for the add command.
+	Allow adding an otherwise ignored submodule path.
+
 --cached::
 	This option is only valid for status and summary commands.  These
 	commands typically use the commit found in the submodule HEAD, but

git-submodule.sh

@@ -5,7 +5,7 @@
 # Copyright (c) 2007 Lars Hjemli
 
 dashless=$(basename "$0" | sed -e 's/-/ /')
-USAGE="[--quiet] add [-b branch] [--reference <repository>] [--] <repository> [<path>]
+USAGE="[--quiet] add [-b branch] [-f|--force] [--reference <repository>] [--] <repository> [<path>]
    or: $dashless [--quiet] status [--cached] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] init [--] [<path>...]
    or: $dashless [--quiet] update [--init] [-N|--no-fetch] [--rebase] [--reference <repository>] [--merge] [--recursive] [--] [<path>...]
@@ -19,6 +19,7 @@ require_work_tree
 
 command=
 branch=
+force=
 reference=
 cached=
 recursive=
@@ -133,6 +134,9 @@ cmd_add()
 			branch=$2
 			shift
 			;;
+		-f | --force)
+			force=$1
+			;;
 		-q|--quiet)
 			GIT_QUIET=1
 			;;
@@ -201,6 +205,14 @@ cmd_add()
 	git ls-files --error-unmatch "$path" > /dev/null 2>&1 &&
 	die "'$path' already exists in the index"
 
+	if test -z "$force" && ! git add --dry-run --ignore-missing "$path" > /dev/null 2>&1
+	then
+		echo >&2 "The following path is ignored by one of your .gitignore files:" &&
+		echo >&2 $path &&
+		echo >&2 "Use -f if you really want to add it."
+		exit 1
+	fi
+
 	# perhaps the path exists and is already a git repo, else clone it
 	if test -e "$path"
 	then
@@ -234,7 +246,7 @@ cmd_add()
 		) || die "Unable to checkout submodule '$path'"
 	fi
 
-	git add --force "$path" ||
+	git add $force "$path" ||
 	die "Failed to add submodule '$path'"
 
 	git config -f .gitmodules submodule."$path".path "$path" &&

t/t7400-submodule-basic.sh

@@ -86,25 +86,28 @@ test_expect_success 'submodule add' '
 	test_cmp empty untracked
 '
 
-test_expect_success 'submodule add to .gitignored path' '
-	echo "refs/heads/master" >expect &&
-	>empty &&
-
+test_expect_success 'submodule add to .gitignored path fails' '
 	(
 		cd addtest-ignore &&
+		cat <<-\EOF >expect &&
+		The following path is ignored by one of your .gitignore files:
+		submod
+		Use -f if you really want to add it.
+		EOF
 		# Does not use test_commit due to the ignore
 		echo "*" > .gitignore &&
 		git add --force .gitignore &&
 		git commit -m"Ignore everything" &&
-		git submodule add "$submodurl" submod &&
-		git submodule init
-	) &&
+		! git submodule add "$submodurl" submod >actual 2>&1 &&
+		test_cmp expect actual
+	)
+'
 
-	rm -f heads head untracked &&
-	inspect addtest/submod ../.. &&
-	test_cmp expect heads &&
-	test_cmp expect head &&
-	test_cmp empty untracked
+test_expect_success 'submodule add to .gitignored path with --force' '
+	(
+		cd addtest-ignore &&
+		git submodule add --force "$submodurl" submod
+	)
 '
 
 test_expect_success 'submodule add --branch' '