Merge branch 'tr/log-full-diff-keep-true-parents' into maint

Output from "git log --full-diff -- <pathspec>" looked strange,
because comparison was done with the previous ancestor that touched
the specified <pathspec>, causing the patches for paths outside the
pathspec to show more than the single commit has changed.

* tr/log-full-diff-keep-true-parents:
  log: use true parents for diff when walking reflogs
  log: use true parents for diff even when rewriting

2 files changed, 28 insertions, 0 deletions

diff --git a/t/t1411-reflog-show.sh b/t/t1411-reflog-show.sh
index 9a105fe21..6f47c0dd0 100755
--- a/t/t1411-reflog-show.sh
+++ b/t/t1411-reflog-show.sh
@@ -144,4 +144,26 @@ test_expect_success 'empty reflog file' '
 	test_cmp expect actual
 '
 
+# This guards against the alternative of showing the diffs vs. the
+# reflog ancestor.  The reflog used is designed to list the commits
+# more than once, so as to exercise the corresponding logic.
+test_expect_success 'git log -g -p shows diffs vs. parents' '
+	test_commit two &&
+	git branch flipflop &&
+	git update-ref refs/heads/flipflop -m flip1 HEAD^ &&
+	git update-ref refs/heads/flipflop -m flop1 HEAD &&
+	git update-ref refs/heads/flipflop -m flip2 HEAD^ &&
+	git log -g -p flipflop >reflog &&
+	grep -v ^Reflog reflog >actual &&
+	git log -1 -p HEAD^ >log.one &&
+	git log -1 -p HEAD >log.two &&
+	(
+		cat log.one; echo
+		cat log.two; echo
+		cat log.one; echo
+		cat log.two
+	) >expect &&
+	test_cmp expect actual
+'
+
 test_done
diff --git a/t/t6012-rev-list-simplify.sh b/t/t6012-rev-list-simplify.sh
index 57ce2395d..fde5e712e 100755
--- a/t/t6012-rev-list-simplify.sh
+++ b/t/t6012-rev-list-simplify.sh
@@ -127,4 +127,10 @@ test_expect_success 'full history simplification without parent' '
 	}
 '
 
+test_expect_success '--full-diff is not affected by --parents' '
+	git log -p --pretty="%H" --full-diff -- file >expected &&
+	git log -p --pretty="%H" --full-diff --parents -- file >actual &&
+	test_cmp expected actual
+'
+
 test_done