Prevent diff machinery from examining assume-unchanged entries on worktree

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/diff-lib.c b/diff-lib.c
index ad2a4cde74e0c2ec6367a7128aa0732f131f6bdf..22da66ef145b3b1642b90e113a4659b43366d452 100644 (file)
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -162,7 +162,8 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
                if (ce_uptodate(ce))
                        continue;
 
-               changed = check_removed(ce, &st);
+               /* If CE_VALID is set, don't look at workdir for file removal */
+               changed = (ce->ce_flags & CE_VALID) ? 0 : check_removed(ce, &st);
                if (changed) {
                        if (changed < 0) {
                                perror(ce->name);
@@ -337,6 +338,8 @@ static void do_oneway_diff(struct unpack_trees_options *o,
        struct rev_info *revs = o->unpack_data;
        int match_missing, cached;
 
+       /* if the entry is not checked out, don't examine work tree */
+       cached = o->index_only || (idx && (idx->ce_flags & CE_VALID));
        /*
         * Backward compatibility wart - "diff-index -m" does
         * not mean "do not ignore merges", but "match_missing".
@@ -344,7 +347,6 @@ static void do_oneway_diff(struct unpack_trees_options *o,
         * But with the revision flag parsing, that's found in
         * "!revs->ignore_merges".
         */
-       cached = o->index_only;
        match_missing = !revs->ignore_merges;
 
        if (cached && idx && ce_stage(idx)) {

diff --git a/t/t4039-diff-assume-unchanged.sh b/t/t4039-diff-assume-unchanged.sh
new file mode 100755 (executable)
index 0000000..9d9498b
--- /dev/null
+++ b/t/t4039-diff-assume-unchanged.sh
@@ -0,0 +1,31 @@
+#!/bin/sh
+
+test_description='diff with assume-unchanged entries'
+
+. ./test-lib.sh
+
+# external diff has been tested in t4020-diff-external.sh
+
+test_expect_success 'setup' '
+       echo zero > zero &&
+       git add zero &&
+       git commit -m zero &&
+       echo one > one &&
+       echo two > two &&
+       git add one two &&
+       git commit -m onetwo &&
+       git update-index --assume-unchanged one &&
+       echo borked >> one &&
+       test "$(git ls-files -v one)" = "h one"
+'
+
+test_expect_success 'diff-index does not examine assume-unchanged entries' '
+       git diff-index HEAD^ -- one | grep -q 5626abf0f72e58d7a153368ba57db4c673c0e171
+'
+
+test_expect_success 'diff-files does not examine assume-unchanged entries' '
+       rm one &&
+       test -z "$(git diff-files -- one)"
+'
+
+test_done