--- a/tests/test-annotate.t	Fri Jan 24 12:01:12 2025 -0500
+++ b/tests/test-annotate.t	Fri Feb 07 16:40:22 2025 -0500
@@ -1217,6 +1217,60 @@
 
   $ cd ..
 
+Annotate should use the starting revision (-r) as base for ancestor checks.
+TODO: Fix Python, which calls introfilectx() first and uses that for ancestor checks.
+
+  $ hg init repo-base
+  $ cd repo-base
+  $ echo A > file
+  $ hg commit -Am "initial"
+  adding file
+  $ echo B >> file
+  $ hg commit -m "linkrev"
+  $ hg up 0
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ echo B >> file
+  $ hg ci -m "linkrev alias"
+  created new head
+  $ echo C >> file
+  $ hg commit -m "change"
+  $ hg merge 1 --tool :local
+  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
+  (branch merge, don't forget to commit)
+  $ hg commit -m "merge"
+  $ hg debugindex file
+     rev linkrev       nodeid    p1-nodeid    p2-nodeid
+       0       0 45f17b21388f 000000000000 000000000000
+       1       1 e338fefefb89 45f17b21388f 000000000000
+       2       3 b2f3b2eded93 e338fefefb89 000000000000
+  $ hg log -G --template '{rev}: {desc}'
+  @    4: merge
+  |\
+  | o  3: change
+  | |
+  | o  2: linkrev alias
+  | |
+  o |  1: linkrev
+  |/
+  o  0: initial
+  
+Line B should be attributed to the linkrev 1, because we base ancestor checks
+from 4 (starting revision), not from 3 (most recent change to the file).
+  $ hg annotate file
+  0: A
+  2: B (no-rhg known-bad-output !)
+  1: B (rhg !)
+  3: C
+  $ echo D >> file
+  $ hg commit -m "another change"
+  $ hg annotate file
+  0: A
+  1: B
+  3: C
+  5: D
+
+  $ cd ..
+
 Issue5360: Deleted chunk in p1 of a merge changeset
 
   $ hg init repo-5360