Merge branch 'rv/maint-index-commit'

* rv/maint-index-commit:
  Make GIT_INDEX_FILE apply to git-commit

diff --cc git-commit.sh
Simple merge

diff --cc t/t7500-commit.sh
index abbf54ba63693bbb3e839786bf97284c22912333,26bd8ee469ad5bad5e4e9700c490cb3e3cb73b83..cf389b81da041e6bcbc7d20cd367b4274001353f
--- 1/t/t7500-commit.sh
--- 2/t/t7500-commit.sh
+++ b/t/t7500-commit.sh
@@@ -90,7 -90,39 +90,39 @@@ test_expect_success 'commit message fro
        echo "standard input msg" |
                GIT_EDITOR=../t7500/add-content git commit \
                        --template "$TEMPLATE" --file - &&
 -      commit_msg_is "standard input msg<unknown>"
 +      commit_msg_is "standard input msg"
  '
  
+ test_expect_success 'using alternate GIT_INDEX_FILE (1)' '
+ 
+       cp .git/index saved-index &&
+       (
+               echo some new content >file &&
+               GIT_INDEX_FILE=.git/another_index &&
+               export GIT_INDEX_FILE &&
+               git add file &&
+               git commit -m "commit using another index" &&
+               git diff-index --exit-code HEAD &&
+               git diff-files --exit-code
+       ) &&
+       cmp .git/index saved-index >/dev/null
+ 
+ '
+ 
+ test_expect_success 'using alternate GIT_INDEX_FILE (2)' '
+ 
+       cp .git/index saved-index &&
+       (
+               rm -f .git/no-such-index &&
+               GIT_INDEX_FILE=.git/no-such-index &&
+               export GIT_INDEX_FILE &&
+               git commit -m "commit using nonexistent index" &&
+               test -z "$(git ls-files)" &&
+               test -z "$(git ls-tree HEAD)"
+ 
+       ) &&
+       cmp .git/index saved-index >/dev/null
+ 
+ '
+ 
  test_done