tree-diff: rework diff_tree() to generate diffs for multiparent cases as well

diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh
index 2e7d73f0906e6a2808706236328470b2d855e9f9..bcae35ac1c93aaf79032db5ee09fd2d3400101f5 100755 (executable)
--- a/t/t4020-diff-external.sh
+++ b/t/t4020-diff-external.sh
@@ -177,7 +177,7 @@ test_expect_success 'no diff with -diff' '
        git diff | grep Binary
 '
 
-echo NULZbetweenZwords | "$PERL_PATH" -pe 'y/Z/\000/' > file
+echo NULZbetweenZwords | perl -pe 'y/Z/\000/' > file
 
 test_expect_success 'force diff with "diff"' '
        echo >.gitattributes "file diff" &&
@@ -193,6 +193,19 @@ test_expect_success 'GIT_EXTERNAL_DIFF with more than one changed files' '
        GIT_EXTERNAL_DIFF=echo git diff
 '
 
+test_expect_success 'GIT_EXTERNAL_DIFF path counter/total' '
+       write_script external-diff.sh <<-\EOF &&
+       echo $GIT_DIFF_PATH_COUNTER of $GIT_DIFF_PATH_TOTAL >>counter.txt
+       EOF
+       >counter.txt &&
+       cat >expect <<-\EOF &&
+       1 of 2
+       2 of 2
+       EOF
+       GIT_EXTERNAL_DIFF=./external-diff.sh git diff &&
+       test_cmp expect counter.txt
+'
+
 test_expect_success 'GIT_EXTERNAL_DIFF generates pretty paths' '
        touch file.ext &&
        git add file.ext &&