t6022: Additional tests checking for unnecessary updates of files

I stumbled across a case, this one not involving a content merge, where
git currently rewrites a file unnecessarily.  A quick audit uncovered two
additional situations (also not involving content merges) with the same
problem.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t6022-merge-rename.sh b/t/t6022-merge-rename.sh
index 8f75762bfb6023d04f7ad695977e97763a9e2e03..c2993fcafec657a63ccbc46c2b07f9bd57c2d652 100755 (executable)
--- a/t/t6022-merge-rename.sh
+++ b/t/t6022-merge-rename.sh
@@ -673,6 +673,97 @@ test_expect_success 'avoid unnecessary update, with D/F conflict' '
        test_cmp expect actual # "df" should have stayed intact
 '
 
+test_expect_success 'setup avoid unnecessary update, dir->(file,nothing)' '
+       git rm -rf . &&
+       git clean -fdqx &&
+       rm -rf .git &&
+       git init &&
+
+       >irrelevant &&
+       mkdir df &&
+       >df/file &&
+       git add -A &&
+       git commit -mA &&
+
+       git checkout -b side
+       git rm -rf df &&
+       git commit -mB &&
+
+       git checkout master &&
+       git rm -rf df &&
+       echo bla >df &&
+       git add -A &&
+       git commit -m "Add a newfile"
+'
+
+test_expect_failure 'avoid unnecessary update, dir->(file,nothing)' '
+       git checkout -q master^0 &&
+       test-chmtime =1000000000 df &&
+       test-chmtime -v +0 df >expect &&
+       git merge side &&
+       test-chmtime -v +0 df >actual &&
+       test_cmp expect actual # "df" should have stayed intact
+'
+
+test_expect_success 'setup avoid unnecessary update, modify/delete' '
+       git rm -rf . &&
+       git clean -fdqx &&
+       rm -rf .git &&
+       git init &&
+
+       >irrelevant &&
+       >file &&
+       git add -A &&
+       git commit -mA &&
+
+       git checkout -b side
+       git rm -f file &&
+       git commit -m "Delete file" &&
+
+       git checkout master &&
+       echo bla >file &&
+       git add -A &&
+       git commit -m "Modify file"
+'
+
+test_expect_failure 'avoid unnecessary update, modify/delete' '
+       git checkout -q master^0 &&
+       test-chmtime =1000000000 file &&
+       test-chmtime -v +0 file >expect &&
+       test_must_fail git merge side &&
+       test-chmtime -v +0 file >actual &&
+       test_cmp expect actual # "file" should have stayed intact
+'
+
+test_expect_success 'setup avoid unnecessary update, rename/add-dest' '
+       git rm -rf . &&
+       git clean -fdqx &&
+       rm -rf .git &&
+       git init &&
+
+       printf "1\n2\n3\n4\n5\n6\n7\n8\n" >file &&
+       git add -A &&
+       git commit -mA &&
+
+       git checkout -b side
+       cp file newfile &&
+       git add -A &&
+       git commit -m "Add file copy" &&
+
+       git checkout master &&
+       git mv file newfile &&
+       git commit -m "Rename file"
+'
+
+test_expect_failure 'avoid unnecessary update, rename/add-dest' '
+       git checkout -q master^0 &&
+       test-chmtime =1000000000 newfile &&
+       test-chmtime -v +0 newfile >expect &&
+       git merge side &&
+       test-chmtime -v +0 newfile >actual &&
+       test_cmp expect actual # "file" should have stayed intact
+'
+
 test_expect_success 'setup merge of rename + small change' '
        git reset --hard &&
        git checkout --orphan rename-plus-small-change &&