fix: report a pin the tracked history lost

scripts/profile_sync.py

@@ -1047,10 +1047,15 @@ class ProfileReport:
     upstream_pin: str | None = None
     upstream_head: str | None = None
     upstream_origin: str | None = None
+    # Repositories whose pin is no ancestor of the branch the profile
+    # tracks: history was rewritten, or the pin lies on another branch.
+    orphaned: list[str] = field(default_factory=list)
 
     def needs_review(self) -> int:
         counts = self.counts or {}
-        return sum(counts.get(status, 0) for status in REVIEW_STATUSES)
+        return sum(counts.get(status, 0) for status in REVIEW_STATUSES) + len(
+            self.orphaned
+        )
 
 
 def select_repo(profile: dict) -> upstream.Repo | None:
@@ -1422,6 +1427,16 @@ def build_report(
     report.pinned_tag = frozen or detect_pinned_tag(
         profile, views, cache_dir, offline
     )
+    if not report.pinned_tag:
+        # A tag or a held pin is off the tracked branch by design.
+        report.orphaned = [
+            f"{view.repo.slug}: pin {view.pin[:8]} is no ancestor of {view.head[:8]}"
+            for view in views
+            if view.pin != view.head
+            and upstream.compare(
+                view.repo, view.pin, view.head, cache_dir, offline
+            ).diverged
+        ]
 
     # A profile carrying no source_ref still has a pin worth writing and a
     # version worth checking, so the revisions above are resolved first.
@@ -1814,6 +1829,8 @@ def format_report(report: ProfileReport, changed_only: bool = False) -> str:
         lines.append("  pin is HEAD: checked for self-consistency")
     for url in report.unread or []:
         lines.append(f"  not read (unsupported host): {url}")
+    for line in report.orphaned:
+        lines.append(f"  orphaned pin: {line}")
     if report.skipped:
         lines.append(f"  skipped: {report.skipped}")
         return "\n".join(lines)

scripts/upstream.py

@@ -122,6 +122,10 @@ class FileChange:
 class CompareResult:
     files: list[FileChange]
     truncated: bool
+    # The forge reports the two revisions on separate lines of history: the
+    # base is no ancestor of the head. A pin in that state survives only
+    # while the forge keeps the orphaned object (advancemame, 2026-10-05).
+    diverged: bool = False
 
 
 def parse_repo(url: str) -> Repo | None:
@@ -526,7 +530,7 @@ def compare(
     else:
         files = _changes_from_github(payload)
     truncated = bool(payload.get("truncated")) or len(files) >= GITHUB_COMPARE_CAP
-    return CompareResult(files, truncated)
+    return CompareResult(files, truncated, payload.get("status") == "diverged")
 
 
 def find_renamed(result: CompareResult, path: str) -> str | None:

tests/test_profile_sync.py

@@ -1510,6 +1510,29 @@ class TestBuildReport(unittest.TestCase):
         self.assertEqual(entry.status, "GONE")
         self.assertIn("written against HEAD", entry.parts[0].reason)
 
+    def test_a_pin_off_the_tracked_history_is_reported(self):
+        # advancemame's master was rewritten: its pin still answered, from
+        # the forge's orphaned objects, and every ref read ANCHORED.
+        self.files[("pinsha", "a.c")] = ["x", "hit"]
+        self.files[("headsha", "a.c")] = ["x", "hit"]
+        profile_sync.upstream.compare = (
+            lambda repo, base, head, cache_dir, offline=False: CompareResult([], False, True)
+        )
+        report = build_report("test", self._profile(["a.c:2"]), self.dir)
+        self.assertEqual(len(report.orphaned), 1)
+        self.assertGreater(report.needs_review(), 0)
+        self.assertIn("orphaned pin", profile_sync.format_report(report))
+
+    def test_a_frozen_tag_is_off_the_branch_on_purpose(self):
+        self.files[("pinsha", "a.c")] = ["x", "hit"]
+        self.files[("headsha", "a.c")] = ["x", "hit"]
+        self.tag_commits = {"v1.6.0": "pinsha"}
+        profile_sync.upstream.compare = (
+            lambda repo, base, head, cache_dir, offline=False: CompareResult([], False, True)
+        )
+        report = build_report("test", self._versioned("1.6.0"), self.dir)
+        self.assertEqual(report.orphaned, [])
+
     def test_pin_on_the_declared_version_tag_is_flagged(self):
         self.files[("pinsha", "a.c")] = ["x", "hit"]
         self.files[("headsha", "a.c")] = ["x", "hit"]