[PATCH 1/2] submodule add: extend force flag to add existing repos

[Stefan Beller]

Currently the force flag in `git submodule add` takes care of possibly
ignored files or when a name collision occurs.

However there is another situation where submodule add comes in handy:
When you already have a gitlink recorded, but no configuration was
done (i.e. no .gitmodules file nor any entry in .git/config) and you
want to generate these config entries. For this situation allow
`git submodule add` to proceed if there is already a submodule at the
given path in the index.

Signed-off-by: Stefan Beller <sbel...@google.com>
---
 git-submodule.sh           | 10 ++++++++--
 t/t7400-submodule-basic.sh | 14 ++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/git-submodule.sh b/git-submodule.sh
index a024a13..3762616 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -207,8 +207,14 @@ cmd_add()
                        tstart
                        s|/*$||
                ')
-       git ls-files --error-unmatch "$sm_path" > /dev/null 2>&1 &&
-       die "$(eval_gettext "'\$sm_path' already exists in the index")"
+       if test -z "$force"
+       then
+               git ls-files --error-unmatch "$sm_path" > /dev/null 2>&1 &&
+               die "$(eval_gettext "'\$sm_path' already exists in the index")"
+       else
+               git ls-files -s "$sm_path" | sane_grep -v "^160000" > /dev/null 
2>&1 &&
+               die "$(eval_gettext "'\$sm_path' already exists in the index 
and is not a submodule")"
+       fi
 
        if test -z "$force" && ! git add --dry-run --ignore-missing "$sm_path" 
> /dev/null 2>&1
        then
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index b77cce8..c09ce0d 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -152,6 +152,20 @@ test_expect_success 'submodule add to .gitignored path 
with --force' '
        )
 '
 
+test_expect_success 'submodule add to reconfigure existing submodule with 
--force' '
+       (
+               cd addtest-ignore &&
+               git submodule add --force bogus-url submod &&
+               git submodule add -b initial "$submodurl" submod-branch &&
+               test "bogus-url" = "$(git config -f .gitmodules 
submodule.submod.url)" &&
+               test "bogus-url" = "$(git config submodule.submod.url)" &&
+               # Restore the url
+               git submodule add --force "$submodurl" submod
+               test "$submodurl" = "$(git config -f .gitmodules 
submodule.submod.url)" &&
+               test "$submodurl" = "$(git config submodule.submod.url)"
+       )
+'
+
 test_expect_success 'submodule add --branch' '
        echo "refs/heads/initial" >expect-head &&
        cat <<-\EOF >expect-heads &&
-- 
2.10.1.353.g1629400