Improve commit->PR lookup reliability

Thomas Stromberg · Thomas Stromberg · commit 5cefdacff256 · 2025-10-27T16:54:52.000-04:00
diff --git a/internal/bot/bot.go b/internal/bot/bot.go
@@ -1132,8 +1132,6 @@ func (c *Coordinator) processPRForChannel(
 
 	// Resolve channel name to ID for API calls
 	channelID := c.slack.ResolveChannelID(ctx, channelName)
-
-	// Check if channel resolution failed
 	if channelID == channelName || (channelName != "" && channelName[0] == '#' && channelID == channelName[1:]) {
 		slog.Warn("could not resolve channel for PR processing",
 			"workspace", c.workspaceName,
@@ -1206,24 +1204,17 @@ func (c *Coordinator) processPRForChannel(
 	// Track that we notified users in this channel for DM delay logic
 	c.notifier.Tracker.UpdateChannelNotification(workspaceID, owner, repo, prNumber)
 
-	// Track user tags in channel asynchronously to avoid blocking thread creation
-	// This is the critical performance optimization - email lookups take 13-20 seconds each
-	// Extract GitHub usernames who are blocked on this PR
+	// Track user tags in channel for DM delay logic
 	blockedUsers := c.extractBlockedUsersFromTurnclient(checkResult)
 	domain := c.configManager.Domain(owner)
 	if len(blockedUsers) > 0 {
 		// Record tags for blocked users synchronously to prevent race with DM sending
-		// This must complete BEFORE DM notifications check tag info
-		// Note: Most lookups hit cache and are instant; occasional cold lookups may delay slightly
-		// but this is necessary for correct DM delay logic
 		lookupCtx, lookupCancel := context.WithTimeout(ctx, 5*time.Second)
 		defer lookupCancel()
 
 		for _, githubUser := range blockedUsers {
-			// Map GitHub username to Slack user ID
 			slackUserID, err := c.userMapper.SlackHandle(lookupCtx, githubUser, owner, domain)
 			if err == nil && slackUserID != "" {
-				// Track with channelID - this will only update on FIRST call per user/PR
 				c.notifier.Tracker.UpdateUserPRChannelTag(workspaceID, slackUserID, channelID, owner, repo, prNumber)
 				slog.Debug("tracked user tag in channel",
 					"workspace", workspaceID,
diff --git a/internal/bot/bot_sprinkler.go b/internal/bot/bot_sprinkler.go
@@ -49,6 +49,88 @@ func eventKey(event client.Event) string {
 	return fmt.Sprintf("%s:%s:%s", event.Timestamp.Format(time.RFC3339Nano), event.URL, event.Type)
 }
 
+// lookupPRsForCheckEvent looks up PRs for a check event that only has a repo URL.
+// This happens when sprinkler's cache doesn't know about the PR yet (timing race).
+func (c *Coordinator) lookupPRsForCheckEvent(ctx context.Context, event client.Event, organization string) []int {
+	commitSHA := ""
+	deliveryID := ""
+	if event.Raw != nil {
+		if sha, ok := event.Raw["commit_sha"].(string); ok {
+			commitSHA = sha
+		}
+		if id, ok := event.Raw["delivery_id"].(string); ok {
+			deliveryID = id
+		}
+	}
+
+	if commitSHA == "" {
+		slog.Warn("check event without PR number or commit SHA - cannot look up PRs",
+			"organization", organization,
+			"url", event.URL,
+			"type", event.Type,
+			"delivery_id", deliveryID)
+		return nil
+	}
+
+	// Extract owner/repo from URL
+	parts := strings.Split(event.URL, "/")
+	if len(parts) < 5 || parts[2] != "github.com" {
+		slog.Error("could not extract repo from check event URL",
+			"organization", organization,
+			"url", event.URL,
+			"error", "invalid URL format")
+		return nil
+	}
+	owner := parts[3]
+	repo := parts[4]
+
+	slog.Info("sprinkler cache miss - looking up PRs for commit via GitHub API",
+		"organization", organization,
+		"owner", owner,
+		"repo", repo,
+		"commit_sha", commitSHA,
+		"type", event.Type,
+		"delivery_id", deliveryID)
+
+	// Look up PRs for this commit using GitHub API
+	// Allow up to 3 minutes for retries (2 min max delay + buffer)
+	lookupCtx, cancel := context.WithTimeout(ctx, 3*time.Minute)
+	defer cancel()
+
+	prNumbers, lookupErr := c.github.FindPRsForCommit(lookupCtx, owner, repo, commitSHA)
+	if lookupErr != nil {
+		slog.Error("failed to look up PRs for commit",
+			"organization", organization,
+			"owner", owner,
+			"repo", repo,
+			"commit_sha", commitSHA,
+			"error", lookupErr,
+			"impact", "will miss this check event",
+			"fallback", "5-minute polling will catch it")
+		return nil
+	}
+
+	if len(prNumbers) == 0 {
+		slog.Debug("no open PRs found for commit - likely push to main",
+			"organization", organization,
+			"owner", owner,
+			"repo", repo,
+			"commit_sha", commitSHA,
+			"type", event.Type)
+		return nil
+	}
+
+	slog.Info("found PRs for commit - processing check event",
+		"organization", organization,
+		"owner", owner,
+		"repo", repo,
+		"commit_sha", commitSHA,
+		"pr_count", len(prNumbers),
+		"pr_numbers", prNumbers)
+
+	return prNumbers
+}
+
 // handleSprinklerEvent processes a single event from sprinkler.
 func (c *Coordinator) handleSprinklerEvent(ctx context.Context, event client.Event, organization string) {
 	// Generate event key using delivery_id if available, otherwise timestamp + URL + type.
@@ -130,10 +212,62 @@ func (c *Coordinator) handleSprinklerEvent(ctx context.Context, event client.Eve
 
 		prNumber, err := parsePRNumberFromURL(event.URL)
 		if err != nil {
-			slog.Error("failed to parse PR number from URL",
+			// Sprinkler sends events with just repo URLs when it can't find PRs for a commit
+			// For check events, try to recover by looking up PRs ourselves
+			if event.Type == "check_suite" || event.Type == "check_run" {
+				prNumbers := c.lookupPRsForCheckEvent(ctx, event, organization)
+				if prNumbers == nil {
+					return
+				}
+
+				// Extract owner/repo from URL for constructing PR URLs
+				parts := strings.Split(event.URL, "/")
+				owner := parts[3]
+				repo := parts[4]
+
+				// Process event for each PR found
+				for _, num := range prNumbers {
+					msg := SprinklerMessage{
+						Type:      event.Type,
+						Event:     event.Type,
+						Repo:      owner + "/" + repo,
+						PRNumber:  num,
+						URL:       fmt.Sprintf("https://github.com/%s/%s/pull/%d", owner, repo, num),
+						Timestamp: event.Timestamp,
+					}
+
+					// Process with timeout
+					processCtx, processCancel := context.WithTimeout(ctx, 30*time.Second)
+					if err := c.processEvent(processCtx, msg); err != nil {
+						slog.Error("error processing recovered check event",
+							"organization", organization,
+							"error", err,
+							"type", event.Type,
+							"url", msg.URL,
+							"repo", msg.Repo,
+							"pr_number", num)
+					}
+					processCancel()
+				}
+				return
+			}
+
+			// Non-check events without PR numbers - just log and ignore
+			var commitSHA, deliveryID string
+			if event.Raw != nil {
+				if sha, ok := event.Raw["commit_sha"].(string); ok {
+					commitSHA = sha
+				}
+				if id, ok := event.Raw["delivery_id"].(string); ok {
+					deliveryID = id
+				}
+			}
+			slog.Debug("ignoring event without PR number",
 				"organization", organization,
 				"url", event.URL,
-				"error", err)
+				"type", event.Type,
+				"commit_sha", commitSHA,
+				"delivery_id", deliveryID)
 			return
 		}
 
diff --git a/internal/bot/polling_test.go b/internal/bot/polling_test.go
@@ -15,12 +15,12 @@ import (
 // See: internal/bot/polling.go:98 - ListClosedPRs(ctx, org, 1)
 func TestClosedPRPollingWindow(t *testing.T) {
 	tests := []struct {
-		name              string
-		prClosedAt        time.Time
-		pollingRunsAt     time.Time
-		lookbackHours     int
-		expectPRIncluded  bool
-		scenario          string
+		name             string
+		prClosedAt       time.Time
+		pollingRunsAt    time.Time
+		lookbackHours    int
+		expectPRIncluded bool
+		scenario         string
 	}{
 		{
 			name:             "PR closed 5 minutes ago - should be caught",
@@ -210,6 +210,10 @@ func TestClosedPRRecoveryScenarios(t *testing.T) {
 // parseTime is a helper to create times on today's date for testing.
 func parseTime(hhMM string) time.Time {
 	now := time.Now()
-	parsed, _ := time.Parse("15:04", hhMM)
+	parsed, err := time.Parse("15:04", hhMM)
+	if err != nil {
+		// This should never happen in tests with valid time strings
+		panic("parseTime: invalid time format " + hhMM + ": " + err.Error())
+	}
 	return time.Date(now.Year(), now.Month(), now.Day(), parsed.Hour(), parsed.Minute(), 0, 0, now.Location())
 }
diff --git a/internal/github/github.go b/internal/github/github.go
@@ -586,6 +586,80 @@ type PRInfo struct {
 	Number    int
 }
 
+// FindPRsForCommit finds all open PRs associated with a commit SHA.
+func (c *Client) FindPRsForCommit(ctx context.Context, owner, repo, sha string) ([]int, error) {
+	if owner == "" || repo == "" || sha == "" {
+		return nil, fmt.Errorf("invalid parameters: owner=%q, repo=%q, sha=%q", owner, repo, sha)
+	}
+
+	slog.Debug("looking up PRs for commit",
+		"owner", owner,
+		"repo", repo,
+		"sha", sha)
+
+	var allPRs []*github.PullRequest
+	err := retry.Do(
+		func() error {
+			var resp *github.Response
+			var err error
+			allPRs, resp, err = c.client.PullRequests.ListPullRequestsWithCommit(
+				ctx,
+				owner,
+				repo,
+				sha,
+				&github.PullRequestListOptions{
+					State: "all", // Include open, closed, and merged
+				},
+			)
+			if err != nil {
+				if resp != nil && resp.StatusCode == http.StatusNotFound {
+					// Commit doesn't exist or no PRs found - don't retry
+					return retry.Unrecoverable(err)
+				}
+				slog.Warn("failed to list PRs for commit, retrying",
+					"owner", owner,
+					"repo", repo,
+					"sha", sha,
+					"error", err)
+				return err
+			}
+			return nil
+		},
+		retry.Attempts(5),
+		retry.Delay(time.Second),
+		retry.MaxDelay(2*time.Minute),
+		retry.DelayType(retry.BackOffDelay),
+		retry.MaxJitter(time.Second),
+		retry.LastErrorOnly(true),
+		retry.Context(ctx),
+	)
+	if err != nil {
+		slog.Debug("no PRs found for commit",
+			"owner", owner,
+			"repo", repo,
+			"sha", sha,
+			"error", err)
+		return []int{}, nil // Return empty list, not error
+	}
+
+	// Extract PR numbers from open PRs only
+	var prNumbers []int
+	for _, pr := range allPRs {
+		if pr.GetState() == "open" {
+			prNumbers = append(prNumbers, pr.GetNumber())
+		}
+	}
+
+	slog.Debug("found PRs for commit",
+		"owner", owner,
+		"repo", repo,
+		"sha", sha,
+		"pr_count", len(prNumbers),
+		"pr_numbers", prNumbers)
+
+	return prNumbers, nil
+}
+
 // Client returns the underlying GitHub client.
 func (c *Client) Client() *github.Client {
 	return c.client
