[PATCH b4 v2 1/4] review: trim trailing quoted when adding a tag

@@ -3297,13 +3297,25 @@ def _insert_trailer_in_reply(reply_text: str, trailer: str) -> str:
     """Append *trailer* as its own bare line in the reply buffer.
 
     The line is added at the end of the maintainer's content, before any
-    trailing ``-- `` signature, grouped with any trailers already there.  The
-    maintainer can move it afterwards — placement is just a sensible default.
+    trailing quoted context or ``-- `` signature, grouped with any trailers
+    already there.  Keeping a trailing quote below the trailer lets the
+    ordinary send-time trimming discard it.  The maintainer can move the
+    trailer afterwards — placement is just a sensible default.
     """
     lines = _normalize_line_endings(reply_text).split('\n')
     sig_idx = next((i for i, ln in enumerate(lines) if ln == '-- '), len(lines))
     head = lines[:sig_idx]
     tail = lines[sig_idx:]
+    quoted_tail: List[str] = []
+    quote_start = len(head)
+    while quote_start and (
+        head[quote_start - 1].startswith(('>', '|'))
+        or not head[quote_start - 1].strip()
+    ):
+        quote_start -= 1
+    if any(line.startswith('>') for line in head[quote_start:]):
+        quoted_tail = head[quote_start:]
+        head = head[:quote_start]
     while head and not head[-1].strip():
         head.pop()
     # Separate from non-trailer content with a blank line so the trailers

@@ -3311,7 +3323,7 @@ def _insert_trailer_in_reply(reply_text: str, trailer: str) -> str:
     if head and not _BARE_TRAILER_RE.match(head[-1]):
         head.append('')
     head.append(trailer)
-    return '\n'.join(head + tail)
+    return '\n'.join(head + quoted_tail + tail)
 
 
 def _remove_trailer_from_reply(reply_text: str, name: str) -> str:

@@ -909,6 +909,40 @@ class TestReplyTrailerEditing:
         # No blank line inserted between the two trailers.
         assert 'Reviewed-by: Me <me@x.com>\nTested-by: Me <me@x.com>' in out
 
+    def test_insert_before_trailing_quote(self) -> None:
+        buf = 'Please fix this.\n\n> context left below my message\n> +old code\n'
+        trailer = 'Reviewed-by: Me <me@x.com>'
+        out = review._insert_trailer_in_reply(buf, trailer)
+        assert out == (
+            'Please fix this.\n\n'
+            'Reviewed-by: Me <me@x.com>\n'
+            '\n'
+            '> context left below my message\n'
+            '> +old code\n'
+        )
+        assert review._trim_quoted_reply(out) == 'Please fix this.\n\n' + trailer
+
+    def test_insert_before_trailing_quote_with_external_review(self) -> None:
+        buf = (
+            'Please fix this.\n'
+            '\n'
+            '> context before external feedback\n'
+            '\n'
+            '| Bot <bot@example.com>:\n'
+            '|\n'
+            '| An external finding.\n'
+            '\n'
+            '> context after external feedback\n'
+        )
+        trailer = 'Reviewed-by: Me <me@x.com>'
+
+        out = review._insert_trailer_in_reply(buf, trailer)
+
+        # The external-review block is scaffolding inside one trailing quoted
+        # run.  Adding a trailer must not split that run and make the quoted
+        # context before the external finding survive send-time trimming.
+        assert review._trim_quoted_reply(out) == 'Please fix this.\n\n' + trailer
+
     def test_remove_drops_matching_bare_line(self) -> None:
         buf = 'Thanks!\n\nReviewed-by: Me <me@x.com>\nAcked-by: Me <me@x.com>'
         out = review._remove_trailer_from_reply(buf, 'reviewed-by')