Merge branch 'jl/submodule-add-by-name'

If you remove a submodule, in order to keep the repository so that
"git checkout" to an older commit in the superproject history can
resurrect the submodule, the real repository will stay in $GIT_DIR
of the superproject.  A later "git submodule add $path" to add a
different submodule at the same path will fail.  Diagnose this case
a bit better, and if the user really wants to add an unrelated
submodule at the same path, give the "--name" option to give it a
place in $GIT_DIR of the superproject that does not conflict with
the original submodule.

* jl/submodule-add-by-name:
  submodule add: Fail when .git/modules/<name> already exists unless forced
  Teach "git submodule add" the --name option

Documentation/git-submodule.txt

@@ -9,7 +9,7 @@ git-submodule - Initialize, update or inspect submodules
 SYNOPSIS
 --------
 [verse]
-'git submodule' [--quiet] add [-b branch] [-f|--force]
+'git submodule' [--quiet] add [-b branch] [-f|--force] [--name <name>]
 	      [--reference <repository>] [--] <repository> [<path>]
 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...]
 'git submodule' [--quiet] init [--] [<path>...]
@@ -265,6 +265,11 @@ OPTIONS
 	Initialize all submodules for which "git submodule init" has not been
 	called so far before updating.
 
+--name::
+	This option is only valid for the add command. It sets the submodule's
+	name to the given string instead of defaulting to its path. The name
+	must be valid as a directory name and may not end with a '/'.
+
 --reference <repository>::
 	This option is only valid for add and update commands.  These
 	commands sometimes need to clone a remote repository. In this case,

Documentation/gitmodules.txt

@@ -18,7 +18,9 @@ working tree, is a text file with a syntax matching the requirements
 of linkgit:git-config[1].
 
 The file contains one subsection per submodule, and the subsection value
-is the name of the submodule. Each submodule section also contains the
+is the name of the submodule. The name is set to the path where the
+submodule has been added unless it was customized with the '--name'
+option of 'git submodule add'. Each submodule section also contains the
 following required keys:
 
 submodule.<name>.path::

git-submodule.sh

@@ -5,7 +5,7 @@
 # Copyright (c) 2007 Lars Hjemli
 
 dashless=$(basename "$0" | sed -e 's/-/ /')
-USAGE="[--quiet] add [-b branch] [-f|--force] [--reference <repository>] [--] <repository> [<path>]
+USAGE="[--quiet] add [-b branch] [-f|--force] [--name <name>] [--reference <repository>] [--] <repository> [<path>]
    or: $dashless [--quiet] status [--cached] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] init [--] [<path>...]
    or: $dashless [--quiet] update [--init] [-N|--no-fetch] [-f|--force] [--rebase] [--reference <repository>] [--merge] [--recursive] [--] [<path>...]
@@ -29,6 +29,7 @@ files=
 nofetch=
 update=
 prefix=
+custom_name=
 
 # The function takes at most 2 arguments. The first argument is the
 # URL that navigates to the submodule origin repo. When relative, this URL
@@ -179,8 +180,9 @@ module_name()
 module_clone()
 {
 	sm_path=$1
-	url=$2
-	reference="$3"
+	name=$2
+	url=$3
+	reference="$4"
 	quiet=
 	if test -n "$GIT_QUIET"
 	then
@@ -189,8 +191,6 @@ module_clone()
 
 	gitdir=
 	gitdir_base=
-	name=$(module_name "$sm_path" 2>/dev/null)
-	test -n "$name" || name="$sm_path"
 	base_name=$(dirname "$name")
 
 	gitdir=$(git rev-parse --git-dir)
@@ -272,6 +272,11 @@ cmd_add()
 			reference="$1"
 			shift
 			;;
+		--name)
+			case "$2" in '') usage ;; esac
+			custom_name=$2
+			shift
+			;;
 		--)
 			shift
 			break
@@ -336,6 +341,13 @@ Use -f if you really want to add it." >&2
 		exit 1
 	fi
 
+	if test -n "$custom_name"
+	then
+		sm_name="$custom_name"
+	else
+		sm_name="$sm_path"
+	fi
+
 	# perhaps the path exists and is already a git repo, else clone it
 	if test -e "$sm_path"
 	then
@@ -347,8 +359,21 @@ Use -f if you really want to add it." >&2
 		fi
 
 	else
-
-		module_clone "$sm_path" "$realrepo" "$reference" || exit
+		if test -d ".git/modules/$sm_name"
+		then
+			if test -z "$force"
+			then
+				echo >&2 "$(eval_gettext "A git directory for '\$sm_name' is found locally with remote(s):")"
+				GIT_DIR=".git/modules/$sm_name" GIT_WORK_TREE=. git remote -v | grep '(fetch)' | sed -e s,^,"  ", -e s,' (fetch)',, >&2
+				echo >&2 "$(eval_gettext "If you want to reuse this local git directory instead of cloning again from")"
+				echo >&2 "  $realrepo"
+				echo >&2 "$(eval_gettext "use the '--force' option. If the local git directory is not the correct repo")"
+				die "$(eval_gettext "or you are unsure what this means choose another name with the '--name' option.")"
+			else
+				echo "$(eval_gettext "Reactivating local git directory for submodule '\$sm_name'.")"
+			fi
+		fi
+		module_clone "$sm_path" "$sm_name" "$realrepo" "$reference" || exit
 		(
 			clear_local_git_env
 			cd "$sm_path" &&
@@ -359,13 +384,13 @@ Use -f if you really want to add it." >&2
 			esac
 		) || die "$(eval_gettext "Unable to checkout submodule '\$sm_path'")"
 	fi
-	git config submodule."$sm_path".url "$realrepo"
+	git config submodule."$sm_name".url "$realrepo"
 
 	git add $force "$sm_path" ||
 	die "$(eval_gettext "Failed to add submodule '\$sm_path'")"
 
-	git config -f .gitmodules submodule."$sm_path".path "$sm_path" &&
-	git config -f .gitmodules submodule."$sm_path".url "$repo" &&
+	git config -f .gitmodules submodule."$sm_name".path "$sm_path" &&
+	git config -f .gitmodules submodule."$sm_name".url "$repo" &&
 	git add --force .gitmodules ||
 	die "$(eval_gettext "Failed to register submodule '\$sm_path'")"
 }
@@ -594,7 +619,7 @@ Maybe you want to use 'update --init'?")"
 
 		if ! test -d "$sm_path"/.git -o -f "$sm_path"/.git
 		then
-			module_clone "$sm_path" "$url" "$reference"|| exit
+			module_clone "$sm_path" "$name" "$url" "$reference" || exit
 			cloned_modules="$cloned_modules;$name"
 			subsha1=
 		else

t/t7400-submodule-basic.sh

@@ -681,4 +681,79 @@ test_expect_success 'moving the superproject does not break submodules' '
 	)
 '
 
+test_expect_success 'submodule add --name allows to replace a submodule with another at the same path' '
+	(
+		cd addtest2 &&
+		(
+			cd repo &&
+			echo "$submodurl/repo" >expect &&
+			git config remote.origin.url >actual &&
+			test_cmp expect actual &&
+			echo "gitdir: ../.git/modules/repo" >expect &&
+			test_cmp expect .git
+		) &&
+		rm -rf repo &&
+		git rm repo &&
+		git submodule add -q --name repo_new "$submodurl/bare.git" repo >actual &&
+		test ! -s actual &&
+		echo "gitdir: ../.git/modules/submod" >expect &&
+		test_cmp expect submod/.git &&
+		(
+			cd repo &&
+			echo "$submodurl/bare.git" >expect &&
+			git config remote.origin.url >actual &&
+			test_cmp expect actual &&
+			echo "gitdir: ../.git/modules/repo_new" >expect &&
+			test_cmp expect .git
+		) &&
+		echo "repo" >expect &&
+		git config -f .gitmodules submodule.repo.path >actual &&
+		test_cmp expect actual &&
+		git config -f .gitmodules submodule.repo_new.path >actual &&
+		test_cmp expect actual&&
+		echo "$submodurl/repo" >expect &&
+		git config -f .gitmodules submodule.repo.url >actual &&
+		test_cmp expect actual &&
+		echo "$submodurl/bare.git" >expect &&
+		git config -f .gitmodules submodule.repo_new.url >actual &&
+		test_cmp expect actual &&
+		echo "$submodurl/repo" >expect &&
+		git config submodule.repo.url >actual &&
+		test_cmp expect actual &&
+		echo "$submodurl/bare.git" >expect &&
+		git config submodule.repo_new.url >actual &&
+		test_cmp expect actual
+	)
+'
+
+test_expect_success 'submodule add with an existing name fails unless forced' '
+	(
+		cd addtest2 &&
+		rm -rf repo &&
+		git rm repo &&
+		test_must_fail git submodule add -q --name repo_new "$submodurl/repo.git" repo &&
+		test ! -d repo &&
+		echo "repo" >expect &&
+		git config -f .gitmodules submodule.repo_new.path >actual &&
+		test_cmp expect actual&&
+		echo "$submodurl/bare.git" >expect &&
+		git config -f .gitmodules submodule.repo_new.url >actual &&
+		test_cmp expect actual &&
+		echo "$submodurl/bare.git" >expect &&
+		git config submodule.repo_new.url >actual &&
+		test_cmp expect actual &&
+		git submodule add -f -q --name repo_new "$submodurl/repo.git" repo &&
+		test -d repo &&
+		echo "repo" >expect &&
+		git config -f .gitmodules submodule.repo_new.path >actual &&
+		test_cmp expect actual&&
+		echo "$submodurl/repo.git" >expect &&
+		git config -f .gitmodules submodule.repo_new.url >actual &&
+		test_cmp expect actual &&
+		echo "$submodurl/repo.git" >expect &&
+		git config submodule.repo_new.url >actual &&
+		test_cmp expect actual
+	)
+'
+
 test_done

t/t7406-submodule-update.sh

@@ -627,7 +627,7 @@ test_expect_success 'submodule add properly re-creates deeper level submodules'
 	(cd super &&
 	 git reset --hard master &&
 	 rm -rf deeper/ &&
-	 git submodule add ../submodule deeper/submodule
+	 git submodule add --force ../submodule deeper/submodule
 	)
 '