Do not retry (or panic in logs) on upload exceptions when the version is no longer scheduled for analysis.

app/lib/shared/exceptions.dart

@@ -51,6 +51,11 @@ class NotAcceptableException extends ResponseException {
       : super._(406, 'NotAcceptable', message);
 }
 
+/// Thrown when part of the underlying analysis task has been aborted.
+class TaskAbortedException extends ResponseException {
+  TaskAbortedException(String message) : super._(400, 'TaskAborted', message);
+}
+
 /// Thrown when request input is invalid, bad payload, wrong querystring, etc.
 class InvalidInputException extends ResponseException {
   InvalidInputException._(String message)

app/lib/task/backend.dart

@@ -38,6 +38,7 @@ import 'package:pub_dev/task/global_lock.dart';
 import 'package:pub_dev/task/handlers.dart';
 import 'package:pub_dev/task/models.dart'
     show
+        AbortedTokenInfo,
         PackageState,
         PackageStateInfo,
         PackageVersionStateInfo,
@@ -454,6 +455,20 @@ class TaskBackend {
         return false;
       }
 
+      state.abortedTokens = [
+        ...state.versions!.entries
+            .where((e) => deselectedVersions.contains(e.key))
+            .map((e) => e.value)
+            .where((vs) => vs.secretToken != null)
+            .map(
+              (vs) => AbortedTokenInfo(
+                token: vs.secretToken!,
+                expires: vs.scheduled.add(maxTaskExecutionTime),
+              ),
+            ),
+        ...?state.abortedTokens,
+      ].where((t) => t.isNotExpired).take(50).toList();
+
       // Make changes!
       state.versions!
         // Remove versions that have been deselected
@@ -467,6 +482,7 @@ class TaskBackend {
             ),
         });
       state.derivePendingAt();
+      state.abortedTokens?.removeWhere((t) => t.expires.isAfter(clock.now()));
 
       _log.info('Update state tracking for $packageName');
       tx.insert(state);
@@ -609,20 +625,18 @@ class TaskBackend {
     InvalidInputException.checkPackageName(package);
     version = InvalidInputException.checkSemanticVersion(version);
 
+    final token = _extractBearerToken(request);
+    if (token == null) {
+      throw AuthenticationException.authenticationRequired();
+    }
+
     final key = PackageState.createKey(_db, runtimeVersion, package);
     final state = await _db.lookupOrNull<PackageState>(key);
-    if (state == null || state.versions![version] == null) {
+    if (state == null) {
       throw NotFoundException.resource('$package/$version');
     }
-    final versionState = state.versions![version]!;
-
-    // Check the secret token
-    if (!versionState.isAuthorized(_extractBearerToken(request))) {
-      throw AuthenticationException.authenticationRequired();
-    }
-    assert(versionState.scheduled != initialTimestamp);
-    assert(versionState.instance != null);
-    assert(versionState.zone != null);
+    final versionState =
+        _authorizeWorkerCallback(package, version, state, token);
 
     // Set expiration of signed URLs to remaining execution time + 5 min to
     // allow for clock skew.
@@ -669,6 +683,11 @@ class TaskBackend {
     InvalidInputException.checkPackageName(package);
     version = InvalidInputException.checkSemanticVersion(version);
 
+    final token = _extractBearerToken(request);
+    if (token == null) {
+      throw AuthenticationException.authenticationRequired();
+    }
+
     String? zone, instance;
     bool isInstanceDone = false;
     final index = await _loadTaskResultIndex(
@@ -685,18 +704,11 @@ class TaskBackend {
     await withRetryTransaction(_db, (tx) async {
       final key = PackageState.createKey(_db, runtimeVersion, package);
       final state = await tx.lookupOrNull<PackageState>(key);
-      if (state == null || state.versions![version] == null) {
+      if (state == null) {
         throw NotFoundException.resource('$package/$version');
       }
-      final versionState = state.versions![version]!;
-
-      // Check the secret token
-      if (!versionState.isAuthorized(_extractBearerToken(request))) {
-        throw AuthenticationException.authenticationRequired();
-      }
-      assert(versionState.scheduled != initialTimestamp);
-      assert(versionState.instance != null);
-      assert(versionState.zone != null);
+      final versionState =
+          _authorizeWorkerCallback(package, version, state, token);
 
       // Update dependencies, if pana summary has dependencies
       if (summary != null && summary.allDependencies != null) {
@@ -1169,6 +1181,38 @@ String? _extractBearerToken(shelf.Request request) {
   return parts.last.trim();
 }
 
+/// Authorize a worker callback for [package] / [version].
+///
+/// Returns the [PackageVersionStateInfo] that the worker is authenticated for.
+/// Or throw [ResponseException] if authorization is not possible.
+PackageVersionStateInfo _authorizeWorkerCallback(
+  String package,
+  String version,
+  PackageState state,
+  String token,
+) {
+  // fixed-time verification of aborted tokens
+  final isKnownAbortedToken = state.abortedTokens
+      ?.map((t) => t.isAuthorized(token))
+      .fold<bool>(false, (a, b) => a || b);
+  if (isKnownAbortedToken ?? false) {
+    throw TaskAbortedException('$package/$version has been aborted.');
+  }
+
+  final versionState = state.versions![version];
+  if (versionState == null) {
+    throw NotFoundException.resource('$package/$version');
+  }
+  // Check the secret token
+  if (!versionState.isAuthorized(token)) {
+    throw AuthenticationException.authenticationRequired();
+  }
+  assert(versionState.scheduled != initialTimestamp);
+  assert(versionState.instance != null);
+  assert(versionState.zone != null);
+  return versionState;
+}
+
 /// Given a list of versions return the list of versions that should be
 /// tracked for analysis.
 ///

app/lib/task/models.dart

@@ -6,6 +6,8 @@ import 'dart:convert' show json;
 
 import 'package:clock/clock.dart';
 import 'package:json_annotation/json_annotation.dart';
+import 'package:pub_dev/admin/actions/actions.dart';
+import 'package:pub_dev/shared/utils.dart';
 
 import '../shared/datastore.dart' as db;
 import '../shared/versions.dart' as shared_versions;
@@ -107,6 +109,12 @@ class PackageState extends db.ExpandoModel<String> {
   @PackageVersionStateMapProperty(required: true)
   Map<String, PackageVersionStateInfo>? versions;
 
+  /// The list of tokens that were removed from this [PackageState].
+  /// When a worker reports back using one of these tokens, they will
+  /// recieve a [TaskAbortedException].
+  @AbortedTokenListProperty()
+  List<AbortedTokenInfo>? abortedTokens;
+
   /// Next [DateTime] at which point some package version becomes pending.
   @db.DateTimeProperty(required: true, indexed: true)
   DateTime? pendingAt;
@@ -407,3 +415,58 @@ enum PackageVersionStatus {
   /// Analysis failed to report a result.
   failed,
 }
+
+/// Tracks a token that was removed from the [PackageState], but a worker
+/// may still use it to report a completed task. Such workers may recieve
+/// an error code that says they shouldn't really panic on the rejection.
+@JsonSerializable()
+class AbortedTokenInfo {
+  final String token;
+  final DateTime expires;
+
+  AbortedTokenInfo({
+    required this.token,
+    required this.expires,
+  });
+
+  factory AbortedTokenInfo.fromJson(Map<String, dynamic> m) =>
+      _$AbortedTokenInfoFromJson(m);
+  Map<String, dynamic> toJson() => _$AbortedTokenInfoToJson(this);
+
+  bool get isNotExpired => clock.now().isBefore(expires);
+
+  bool isAuthorized(String token) {
+    return fixedTimeEquals(this.token, token) && isNotExpired;
+  }
+}
+
+/// A [db.Property] encoding a List os [AbortedTokenInfo] as JSON.
+class AbortedTokenListProperty extends db.Property {
+  const AbortedTokenListProperty({String? propertyName, bool required = false})
+      : super(propertyName: propertyName, required: required, indexed: false);
+
+  @override
+  Object? encodeValue(
+    db.ModelDB mdb,
+    Object? value, {
+    bool forComparison = false,
+  }) =>
+      json.encode(
+          (value as List<AbortedTokenInfo>?)?.map((e) => e.toJson()).toList());
+
+  @override
+  Object? decodePrimitiveValue(
+    db.ModelDB mdb,
+    Object? value,
+  ) =>
+      value == null
+          ? null
+          : (json.decode(value as String) as List?)
+              ?.map((e) => AbortedTokenInfo.fromJson(e as Map<String, dynamic>))
+              .toList();
+
+  @override
+  bool validate(db.ModelDB mdb, Object? value) =>
+      super.validate(mdb, value) &&
+      (value == null || value is List<AbortedTokenInfo>);
+}

pkg/pub_worker/lib/src/analyze.dart

@@ -92,12 +92,14 @@ Future<void> analyze(Payload payload) async {
                 'analyze.',
           );
         }
+      } on TaskAbortedException catch (e, st) {
+        _log.warning(
+            'Task was aborted when uploading ${payload.package} / ${p.version}',
+            e,
+            st);
       } catch (e, st) {
         _log.shout(
-          'failed to process ${payload.package} / ${p.version}',
-          e,
-          st,
-        );
+            'failed to process ${payload.package} / ${p.version}', e, st);
       }
     }
   } finally {

pkg/pub_worker/lib/src/upload.dart

@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:convert';
 import 'dart:io';
 
 import 'package:_pub_shared/data/package_api.dart' show UploadInfo;
@@ -40,6 +41,15 @@ Future<void> upload(
         ));
       final res = await Response.fromStream(await client.send(req));
 
+      // Special case `TaskAborted` response code, it means that the analysis
+      // is no longer selected or the secret token timed out / was replaced
+      // (it may need a different analysis round).
+      if (res.statusCode == 400 &&
+          _extractExceptionCode(res) == 'TaskAborted') {
+        _log.warning(
+            'Task aborted, failed to upload: $filename, status = ${res.statusCode}');
+        throw TaskAbortedException(res.body);
+      }
       if (400 <= res.statusCode && res.statusCode < 500) {
         _log.shout('Failed to upload: $filename, status = ${res.statusCode}');
         throw UploadException(
@@ -80,3 +90,26 @@ final class UploadException implements Exception {
 final class IntermittentUploadException extends UploadException {
   IntermittentUploadException(String message) : super(message);
 }
+
+final class TaskAbortedException extends UploadException {
+  TaskAbortedException(String message) : super(message);
+}
+
+/// Extract `error.code` from JSON body in [res].
+String? _extractExceptionCode(Response res) {
+  try {
+    final map = json.decode(res.body);
+    if (map is! Map) {
+      return null;
+    }
+    final error = map['error'];
+    if (error is! Map) {
+      return null;
+    }
+    final code = error['code'];
+    return code?.toString();
+  } on FormatException catch (_) {
+    // ignore
+  }
+  return null;
+}