test(scanner): classify raw enumeration replay (#7339)

Record bounded first/last raw entry markers in the restart diagnostic worker and have the driver classify repeated raw windows when retained coverage does not advance.

Co-authored-by: zhi22915 <qiuzgang@gmail.com>

crates/scanner/src/scanner_folder/tests/enumeration_restart.rs

@@ -13,6 +13,8 @@ struct Observation {
     limit: u64,
     entries: u64,
     name_bytes: u64,
+    first_entry: Option<String>,
+    last_entry: Option<String>,
 }
 
 static OBSERVATION: Mutex<Option<Observation>> = Mutex::new(None);
@@ -24,6 +26,12 @@ pub(in crate::scanner_folder) fn observe_raw_entry(dir: &str, name: &std::ffi::O
     if let Some(observation) = guard.as_mut()
         && Path::new(dir).starts_with(&observation.root)
     {
+        let relative_dir = Path::new(dir)
+            .strip_prefix(&observation.root)
+            .unwrap_or_else(|_| Path::new(""));
+        let entry_marker = relative_dir.join(name).to_string_lossy().to_string();
+        observation.first_entry.get_or_insert_with(|| entry_marker.clone());
+        observation.last_entry = Some(entry_marker);
         observation.entries += 1;
         observation.name_bytes += u64::try_from(name.as_encoded_bytes().len()).expect("bounded entry name");
         if observation.entries >= observation.limit {
@@ -103,6 +111,8 @@ async fn round(request: &Request) -> serde_json::Value {
         limit: request.raw_entry_budget,
         entries: 0,
         name_bytes: 0,
+        first_entry: None,
+        last_entry: None,
     });
     let _observation_guard = ObservationGuard;
     let result = scan_data_folder(
@@ -141,6 +151,7 @@ async fn round(request: &Request) -> serde_json::Value {
         "schema": 1, "pid": std::process::id(), "round": request.round,
         "objects_expected": request.objects, "raw_entry_budget": request.raw_entry_budget,
         "raw_entries": observation.entries, "raw_name_bytes": observation.name_bytes,
+        "raw_first_entry": observation.first_entry, "raw_last_entry": observation.last_entry,
         "objects_processed": budget.progress().0,
         "objects_before": before, "objects_retained": retained.objects,
         "versions_retained": retained.versions, "bytes_retained": retained.size,

scripts/diagnose_scanner_enumeration_restart.py

@@ -37,6 +37,10 @@ def validate_report(report, *, round_number, pid, objects, budget):
         raise ValueError("nonempty fixture must observe raw entries; budget hook may not have run")
     if report["raw_entries"] > budget:
         raise ValueError("raw-entry budget exceeded; no unbudgeted tail is permitted")
+    for key in ("raw_first_entry", "raw_last_entry"):
+        value = report.get(key)
+        if type(value) is not str or not 0 < len(value.encode("utf-8")) <= 512:
+            raise ValueError(f"invalid raw entry marker: {key}")
     if type(report.get("snapshot_complete")) is not bool:
         raise ValueError("missing explicit completeness")
     if report.get("outcome") not in ("complete", "partial", "cancelled_without_cache"):
@@ -49,6 +53,13 @@ def converged(report, objects):
                     ("objects_retained", "versions_retained", "bytes_retained")))
 
 
+def replays_raw_window(previous, current):
+    return (previous["raw_first_entry"] == current["raw_first_entry"]
+            and previous["raw_last_entry"] == current["raw_last_entry"]
+            and previous["objects_retained"] == current["objects_before"]
+            and current["objects_retained"] == previous["objects_retained"])
+
+
 def run(args):
     binary = args.test_binary.resolve(strict=True)
     listed = subprocess.run([str(binary), WORKER, "--exact", "--list"],
@@ -58,6 +69,7 @@ def run(args):
     workspace = args.output.resolve()
     workspace.mkdir()  # Refuse reuse/overwrite of previous evidence or customer data.
     reports = []
+    replayed_raw_window = False
     for round_number in range(args.rounds):
         request = {"workspace": str(workspace), "objects": args.objects,
                    "raw_entry_budget": args.raw_entry_budget, "round": round_number}
@@ -87,12 +99,15 @@ def run(args):
                             objects=args.objects, budget=args.raw_entry_budget)
         if reports and report["objects_before"] != reports[-1]["objects_retained"]:
             raise ValueError("cache coverage did not survive the process boundary")
+        if reports and replays_raw_window(reports[-1], report):
+            replayed_raw_window = True
         reports.append(report)
         print(json.dumps(report, sort_keys=True), flush=True)
         if converged(report, args.objects):
             print("PASS: bounded scanner-worker restart convergence for this fixture only")
             return 0
-    print("FAIL: fixed-budget restart convergence not established; R-E gate remains unmet",
+    reason = "replayed raw enumeration window" if replayed_raw_window else "no bounded restart convergence"
+    print(f"FAIL: fixed-budget restart convergence not established ({reason}); R-E gate remains unmet",
           file=sys.stderr)
     return 1
 

scripts/test_diagnose_scanner_enumeration_restart.py

@@ -2,7 +2,7 @@
 
 import unittest
 
-from diagnose_scanner_enumeration_restart import converged, validate_report
+from diagnose_scanner_enumeration_restart import converged, replays_raw_window, validate_report
 
 
 class ReportTests(unittest.TestCase):
@@ -10,6 +10,8 @@ class ReportTests(unittest.TestCase):
         return dict(schema=1, round=0, pid=123, objects_expected=4, raw_entry_budget=16,
                     raw_entries=8, raw_name_bytes=64, objects_before=0, objects_retained=4,
                     versions_retained=4, bytes_retained=4, objects_processed=4,
+                    raw_first_entry="bucket/object-0000",
+                    raw_last_entry="bucket/object-0003/xl.meta",
                     snapshot_complete=True, outcome="complete")
 
     def validate(self, report):
@@ -42,6 +44,14 @@ class ReportTests(unittest.TestCase):
         with self.assertRaises(ValueError):
             self.validate(report)
 
+    def test_missing_or_oversized_raw_marker_rejected(self):
+        for value in (None, True, "", "x" * 513):
+            with self.subTest(value=value):
+                report = self.report()
+                report["raw_first_entry"] = value
+                with self.assertRaises(ValueError):
+                    self.validate(report)
+
     def test_complete_coverage_without_entry_observation_rejected(self):
         report = self.report()
         report["raw_entries"] = 0
@@ -68,6 +78,20 @@ class ReportTests(unittest.TestCase):
             with self.assertRaises(ValueError):
                 self.validate(report)
 
+    def test_repeated_raw_window_without_retained_progress_is_diagnosed(self):
+        previous = self.report()
+        previous["objects_retained"] = 0
+        previous["versions_retained"] = 0
+        previous["bytes_retained"] = 0
+        previous["objects_processed"] = 0
+        previous["snapshot_complete"] = False
+        previous["outcome"] = "cancelled_without_cache"
+        current = dict(previous, round=1, pid=124, objects_before=0)
+        self.assertTrue(replays_raw_window(previous, current))
+
+        advanced = dict(current, objects_retained=1)
+        self.assertFalse(replays_raw_window(previous, advanced))
+
 
 if __name__ == "__main__":
     unittest.main()