[PATCH 3/7] git submodule add: Fix naming clash handling

[Petr Baudis <pasky@suse.cz>]

This patch fixes git submodule add behaviour when we add submodule
living at a same path as logical name of existing submodule. This
can happen e.g. in case the user git mv's the previous submodule away
and then git submodule add's another under the same name.

A test-case is obviously included.

This is not completely satisfactory since .git/config cross-commit
conflicts can still occur. A question is whether this is worth
handling, maybe it would be worth adding some kind of randomization
of the autogenerated submodule name, e.g. appending $$ or a timestamp.

Signed-off-by: Petr Baudis <pasky@suse.cz>
---

 git-submodule.sh           |   15 ++++++++++++---
 t/t7400-submodule-basic.sh |   11 +++++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/git-submodule.sh b/git-submodule.sh
index 9228f56..a93547b 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -192,10 +192,19 @@ cmd_add()
 	git add "$path" ||
 	die "Failed to add submodule '$path'"
 
-	git config -f .gitmodules submodule."$path".path "$path" &&
-	git config -f .gitmodules submodule."$path".url "$repo" &&
+	name="$path"
+	if git config -f .gitmodules submodule."$name".path; then
+		name="$path~"; i=1;
+		while git config -f .gitmodules submodule."$name".path; do
+			name="$path~$i"
+			i=$((i+1))
+		done
+	fi
+
+	git config -f .gitmodules submodule."$name".path "$path" &&
+	git config -f .gitmodules submodule."$name".url "$repo" &&
 	git add .gitmodules ||
-	die "Failed to register submodule '$path'"
+	die "Failed to register submodule '$path' (name '$name')"
 }
 
 #
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index ab5eb1e..092dffc 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -235,4 +235,15 @@ test_expect_success 'submodule add -b' '
 
 '
 
+test_expect_success 'submodule add auto-naming clash' '
+
+	git submodule add "$(pwd)/init2/.git" example &&
+	test -d example/.git &&
+	[ "$(git config -f .gitmodules submodule.example.url)" = "$(pwd)/init2" ] &&
+	[ "$(git config -f .gitmodules submodule.example.path)" = "init" ]
+	[ "$(git config -f .gitmodules submodule.example~.url)" = "$(pwd)/init2/.git" ] &&
+	[ "$(git config -f .gitmodules submodule.example~.path)" = "example" ]
+
+'
+
 test_done