Prefetch: Avoid setting PreloadingAttempt's outcome for not started prefetch

This is more general approach of crrev.com/c/6395915. The concept of
`PreloadingAttempt`'s `PreloadingTriggeringOutcome` is to record the
outcomes of started trigger's. Therefore,
`PrefetchContainer::SetTriggeringOutcomeAndFailureReasonFromStatus`
should only be called once prefetching has actually started, and not for
ineligible or not started triggers (e.g., holdback triggers, triggers
waiting on a queue).

This attempts to fix the bug reported in crbug.com/404703517 and
reproduced in crrev.com/c/6407453, crrev.com/c/6395795. For more
information, please see this crbug.

Bug: 404703517
Change-Id: I95f5d8d30bef52fdb59ce603e510c9b1124279ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6406754
Commit-Queue: Taiyo Mizuhashi <taiyo@chromium.org>
Reviewed-by: Ken Okada <kenoss@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1439443}

content/browser/preloading/prefetch/prefetch_container.cc

@@ -171,9 +171,9 @@ std::optional<PreloadingTriggeringOutcome> TriggeringOutcomeFromStatus(
 }
 
 // Returns true if SetPrefetchStatus(|status|) can be called after a prefetch
-// has already been marked as failed or heldback. We ignore such status updates
+// has already been marked as failed. We ignore such status updates
 // as they may end up overwriting the initial failure reason.
-bool StatusUpdateIsPossibleAfterFailureOrHeldback(PrefetchStatus status) {
+bool StatusUpdateIsPossibleAfterFailure(PrefetchStatus status) {
   switch (status) {
     case PrefetchStatus::kPrefetchEvictedAfterCandidateRemoved:
     case PrefetchStatus::kPrefetchIsStale:
@@ -686,18 +686,15 @@ void PrefetchContainer::SetTriggeringOutcomeAndFailureReasonFromStatus(
 
   if (old_prefetch_status &&
       (TriggeringOutcomeFromStatus(old_prefetch_status.value()) ==
-           PreloadingTriggeringOutcome::kFailure ||
-       old_prefetch_status.value() == PrefetchStatus::kPrefetchHeldback)) {
-    if (StatusUpdateIsPossibleAfterFailureOrHeldback(new_prefetch_status)) {
-      // Note that `StatusUpdateIsPossibleAfterFailureOrHeldback()` implies that
+       PreloadingTriggeringOutcome::kFailure)) {
+    if (StatusUpdateIsPossibleAfterFailure(new_prefetch_status)) {
+      // Note that `StatusUpdateIsPossibleAfterFailure()` implies that
       // the new status is a failure.
       CHECK(TriggeringOutcomeFromStatus(new_prefetch_status) ==
             PreloadingTriggeringOutcome::kFailure);
 
-      // Skip this update since 1) if the triggering outcome has already been
-      // updated to kFailure, we don't need to overwrite it 2) if the status is
-      // marked as holdback, we don't need to update the triggering outcome or
-      // the failure reason anymore as it is not meaningful.
+      // Skip this update since if the triggering outcome has already been
+      // updated to kFailure, we don't need to overwrite it.
       return;
     } else {
       SCOPED_CRASH_KEY_NUMBER("PrefetchContainer", "prefetch_status_from",
@@ -831,7 +828,14 @@ void PrefetchContainer::SetPrefetchStatusWithoutUpdatingTriggeringOutcome(
 }
 
 void PrefetchContainer::SetPrefetchStatus(PrefetchStatus prefetch_status) {
-  SetTriggeringOutcomeAndFailureReasonFromStatus(prefetch_status);
+  // The concept of `PreloadingAttempt`'s `PreloadingTriggeringOutcome` is to
+  // record the outcomes of started triggers. Therefore, this should
+  // only be called once prefetching has actually started, and not for
+  // ineligible or eligibled but not started triggers (e.g., holdback triggers,
+  // triggers waiting on a queue).
+  if (GetLoadState() == LoadState::kStarted) {
+    SetTriggeringOutcomeAndFailureReasonFromStatus(prefetch_status);
+  }
   SetPrefetchStatusWithoutUpdatingTriggeringOutcome(prefetch_status);
 }
 

content/browser/preloading/prefetch/prefetch_container.h

@@ -830,6 +830,8 @@ class CONTENT_EXPORT PrefetchContainer {
 
   // Updates `attempt_`'s outcome and failure reason based on
   // `new_prefetch_status`.
+  // This should only be called after the prefetch is started, because
+  // `attempt_` is degined to record the outcome or failure of started triggers.
   void SetTriggeringOutcomeAndFailureReasonFromStatus(
       PrefetchStatus new_prefetch_status);
 

content/browser/preloading/prefetch/prefetch_service_unittest.cc

@@ -5481,6 +5481,243 @@ TEST_P(PrefetchServiceAlwaysBlockUntilHeadTest,
       true, 2);
 }
 
+// Tests that the prefetch eviction for eligible but not started triggers (i.e.
+// `PreloadingAttempt`'s `PreloadingHoldbackStatus` is `kUnspecified`) causes no
+// crash. This is a regression test of crbug.com/404703517.
+TEST_P(PrefetchServiceTest, PrefetchEvictionForEligibleButNotStartedPrefetch) {
+  NavigateAndCommit(GURL("https://example.com"));
+  MakePrefetchService(
+      std::make_unique<testing::NiceMock<MockPrefetchServiceDelegate>>(
+          /*num_on_prefetch_likely_calls=*/2));
+
+  const auto url_1 = GURL("https://example.com/one");
+  const auto url_2 = GURL("https://example.com/two");
+  auto candidate_1 = blink::mojom::SpeculationCandidate::New();
+  candidate_1->url = url_1;
+  candidate_1->action = blink::mojom::SpeculationAction::kPrefetch;
+  candidate_1->eagerness = blink::mojom::SpeculationEagerness::kEager;
+  candidate_1->referrer = blink::mojom::Referrer::New();
+  auto candidate_2 = candidate_1.Clone();
+  candidate_2->url = url_2;
+
+  // Send `candidate_1` and `candidate_2`.
+  std::vector<blink::mojom::SpeculationCandidatePtr> candidates;
+  candidates.push_back(candidate_1.Clone());
+  candidates.push_back(candidate_2.Clone());
+  auto* prefetch_document_manager =
+      PrefetchDocumentManager::GetOrCreateForCurrentDocument(main_rfh());
+  prefetch_document_manager->ProcessCandidates(candidates);
+  task_environment()->RunUntilIdle();
+
+  PrefetchService* prefetch_service =
+      BrowserContextImpl::From(browser_context())->GetPrefetchService();
+  base::WeakPtr<PrefetchContainer> prefetch_container1, prefetch_container2;
+  std::tie(std::ignore, prefetch_container1) =
+      prefetch_service->GetAllForUrlWithoutRefAndQueryForTesting(
+          PrefetchContainer::Key(MainDocumentToken(), url_1))[0];
+  std::tie(std::ignore, prefetch_container2) =
+      prefetch_service->GetAllForUrlWithoutRefAndQueryForTesting(
+          PrefetchContainer::Key(MainDocumentToken(), url_2))[0];
+
+  // `candidate_1` should be started, while `candidate_2` stays in a queue.
+  ASSERT_EQ(prefetch_container1->GetLoadState(),
+            PrefetchContainer::LoadState::kStarted);
+  ASSERT_EQ(prefetch_container2->GetLoadState(),
+            PrefetchContainer::LoadState::kEligible);
+
+  // Try to evict.
+  prefetch_service->EvictPrefetchesForBrowsingDataRemoval(
+      BrowsingDataFilterBuilder::Create(
+          BrowsingDataFilterBuilder::Mode::kPreserve)
+          ->BuildStorageKeyFilter(),
+      PrefetchStatus::kPrefetchEvictedAfterBrowsingDataRemoved);
+
+  // - `candidate_1` should have `PreloadingEligibility::kEligible`,
+  //   `PreloadingHoldbackStatus::kAllowed` and
+  //   `PreloadingTriggeringOutcome::kFailure` as
+  //   `kPrefetchEvictedAfterBrowsingDataRemoved`.
+  // - `candidate_2` should have `PreloadingEligibility::kEligible` but
+  //   `PreloadingHoldbackStatus::kUnspecified` (as the holdback status will be
+  //   determined when the prefetch is actually started) and
+  //   `PreloadingTriggeringOutcome::kUnspecified`.
+  {
+    const auto source_id = ForceLogsUploadAndGetUkmId();
+    auto actual_attempts = test_ukm_recorder()->GetEntries(
+        ukm::builders::Preloading_Attempt::kEntryName,
+        test::kPreloadingAttemptUkmMetrics);
+    ASSERT_EQ(actual_attempts.size(), 2u);
+    std::vector<ukm::TestUkmRecorder::HumanReadableUkmEntry> expected_attempts =
+        {attempt_entry_builder()->BuildEntry(
+             source_id, PreloadingType::kPrefetch,
+             PreloadingEligibility::kEligible,
+             PreloadingHoldbackStatus::kAllowed,
+             PreloadingTriggeringOutcome::kFailure,
+             ToPreloadingFailureReason(
+                 PrefetchStatus::kPrefetchEvictedAfterBrowsingDataRemoved),
+             /*accurate=*/false,
+             /*ready_time=*/std::nullopt,
+             blink::mojom::SpeculationEagerness::kEager),
+         attempt_entry_builder()->BuildEntry(
+             source_id, PreloadingType::kPrefetch,
+             PreloadingEligibility::kEligible,
+             PreloadingHoldbackStatus::kUnspecified,
+             PreloadingTriggeringOutcome::kUnspecified,
+             PreloadingFailureReason::kUnspecified,
+             /*accurate=*/false,
+             /*ready_time=*/std::nullopt,
+             blink::mojom::SpeculationEagerness::kEager)};
+    ASSERT_THAT(actual_attempts,
+                testing::UnorderedElementsAreArray(expected_attempts))
+        << test::ActualVsExpectedUkmEntriesToString(actual_attempts,
+                                                    expected_attempts);
+  }
+}
+
+// Tests that the prefetch eviction during eligiblity check (i.e.
+// `PreloadingAttempt`'s `PreloadingEligibility` is `kUnspecified`) causes no
+// crash. This is a regression test of crbug.com/404703517.
+TEST_P(PrefetchServiceTest, PrefetchEvictionDuringEligiblityCheck) {
+  NavigateAndCommit(GURL("https://example.com"));
+  MakePrefetchService(
+      std::make_unique<testing::NiceMock<MockPrefetchServiceDelegate>>(
+          /*num_on_prefetch_likely_calls=*/1));
+  PrefetchService* prefetch_service =
+      BrowserContextImpl::From(browser_context())->GetPrefetchService();
+
+  // Pause the elibility check.
+  base::test::TestFuture<base::OnceClosure> eligibility_check_callback_future;
+  prefetch_service->SetDelayEligibilityCheckForTesting(base::BindRepeating(
+      [](base::test::TestFuture<base::OnceClosure>*
+             eligibility_check_callback_future,
+         base::OnceClosure callback) {
+        eligibility_check_callback_future->SetValue(std::move(callback));
+      },
+      base::Unretained(&eligibility_check_callback_future)));
+
+  const auto url_1 = GURL("https://example.com/one");
+  auto candidate_1 = blink::mojom::SpeculationCandidate::New();
+  candidate_1->url = url_1;
+  candidate_1->action = blink::mojom::SpeculationAction::kPrefetch;
+  candidate_1->eagerness = blink::mojom::SpeculationEagerness::kEager;
+  candidate_1->referrer = blink::mojom::Referrer::New();
+
+  // Send `candidate_1`;
+  std::vector<blink::mojom::SpeculationCandidatePtr> candidates;
+  candidates.push_back(candidate_1.Clone());
+  auto* prefetch_document_manager =
+      PrefetchDocumentManager::GetOrCreateForCurrentDocument(main_rfh());
+  prefetch_document_manager->ProcessCandidates(candidates);
+  task_environment()->RunUntilIdle();
+
+  base::WeakPtr<PrefetchContainer> prefetch_container1;
+  std::tie(std::ignore, prefetch_container1) =
+      prefetch_service->GetAllForUrlWithoutRefAndQueryForTesting(
+          PrefetchContainer::Key(MainDocumentToken(), url_1))[0];
+
+  // `candidate_1` should be on a way of eligibility check.
+  ASSERT_EQ(prefetch_container1->GetLoadState(),
+            PrefetchContainer::LoadState::kNotStarted);
+
+  // Try to evict.
+  prefetch_service->EvictPrefetchesForBrowsingDataRemoval(
+      BrowsingDataFilterBuilder::Create(
+          BrowsingDataFilterBuilder::Mode::kPreserve)
+          ->BuildStorageKeyFilter(),
+      PrefetchStatus::kPrefetchEvictedAfterBrowsingDataRemoved);
+  {
+    const auto source_id = ForceLogsUploadAndGetUkmId();
+    auto actual_attempts = test_ukm_recorder()->GetEntries(
+        ukm::builders::Preloading_Attempt::kEntryName,
+        test::kPreloadingAttemptUkmMetrics);
+    ASSERT_EQ(actual_attempts.size(), 1u);
+    std::vector<ukm::TestUkmRecorder::HumanReadableUkmEntry> expected_attempts =
+        {attempt_entry_builder()->BuildEntry(
+            source_id, PreloadingType::kPrefetch,
+            PreloadingEligibility::kUnspecified,
+            PreloadingHoldbackStatus::kUnspecified,
+            PreloadingTriggeringOutcome::kUnspecified,
+            PreloadingFailureReason::kUnspecified,
+            /*accurate=*/false,
+            /*ready_time=*/std::nullopt,
+            blink::mojom::SpeculationEagerness::kEager)};
+    ASSERT_THAT(actual_attempts,
+                testing::UnorderedElementsAreArray(expected_attempts))
+        << test::ActualVsExpectedUkmEntriesToString(actual_attempts,
+                                                    expected_attempts);
+  }
+
+  prefetch_service->SetDelayEligibilityCheckForTesting(base::NullCallback());
+}
+
+// Tests that the prefetch eviction for heldback triggers causes no crash. This
+// is a regression test of crbug.com/404703517.
+TEST_P(PrefetchServiceTest, PrefetchEvictionWhenHoldback) {
+  content::test::PreloadingConfigOverride preloading_config_override;
+  preloading_config_override.SetHoldback(
+      PreloadingType::kPrefetch,
+      content_preloading_predictor::kSpeculationRules, true);
+
+  NavigateAndCommit(GURL("https://example.com"));
+  MakePrefetchService(
+      std::make_unique<testing::NiceMock<MockPrefetchServiceDelegate>>(
+          /*num_on_prefetch_likely_calls=*/1));
+  PrefetchService* prefetch_service =
+      BrowserContextImpl::From(browser_context())->GetPrefetchService();
+
+  const auto url_1 = GURL("https://example.com/one");
+  auto candidate_1 = blink::mojom::SpeculationCandidate::New();
+  candidate_1->url = url_1;
+  candidate_1->action = blink::mojom::SpeculationAction::kPrefetch;
+  candidate_1->eagerness = blink::mojom::SpeculationEagerness::kEager;
+  candidate_1->referrer = blink::mojom::Referrer::New();
+
+  // Send `candidate_1`;
+  std::vector<blink::mojom::SpeculationCandidatePtr> candidates;
+  candidates.push_back(candidate_1.Clone());
+  auto* prefetch_document_manager =
+      PrefetchDocumentManager::GetOrCreateForCurrentDocument(main_rfh());
+  prefetch_document_manager->ProcessCandidates(candidates);
+  task_environment()->RunUntilIdle();
+
+  base::WeakPtr<PrefetchContainer> prefetch_container1;
+  std::tie(std::ignore, prefetch_container1) =
+      prefetch_service->GetAllForUrlWithoutRefAndQueryForTesting(
+          PrefetchContainer::Key(MainDocumentToken(), url_1))[0];
+  task_environment()->RunUntilIdle();
+
+  // `candidate_1` should be failed as heldback
+  ASSERT_EQ(prefetch_container1->GetLoadState(),
+            PrefetchContainer::LoadState::kFailedHeldback);
+
+  // Try to evict.
+  prefetch_service->EvictPrefetchesForBrowsingDataRemoval(
+      BrowsingDataFilterBuilder::Create(
+          BrowsingDataFilterBuilder::Mode::kPreserve)
+          ->BuildStorageKeyFilter(),
+      PrefetchStatus::kPrefetchEvictedAfterBrowsingDataRemoved);
+  {
+    const auto source_id = ForceLogsUploadAndGetUkmId();
+    auto actual_attempts = test_ukm_recorder()->GetEntries(
+        ukm::builders::Preloading_Attempt::kEntryName,
+        test::kPreloadingAttemptUkmMetrics);
+    ASSERT_EQ(actual_attempts.size(), 1u);
+    std::vector<ukm::TestUkmRecorder::HumanReadableUkmEntry> expected_attempts =
+        {attempt_entry_builder()->BuildEntry(
+            source_id, PreloadingType::kPrefetch,
+            PreloadingEligibility::kEligible,
+            PreloadingHoldbackStatus::kHoldback,
+            PreloadingTriggeringOutcome::kUnspecified,
+            PreloadingFailureReason::kUnspecified,
+            /*accurate=*/false,
+            /*ready_time=*/std::nullopt,
+            blink::mojom::SpeculationEagerness::kEager)};
+    ASSERT_THAT(actual_attempts,
+                testing::UnorderedElementsAreArray(expected_attempts))
+        << test::ActualVsExpectedUkmEntriesToString(actual_attempts,
+                                                    expected_attempts);
+  }
+}
+
 class PrefetchServiceNewLimitsTest
     : public PrefetchServiceTestBase,
       public WithPrefetchServiceRearchParam,