From 13ffd0b902057a369474ae1ead1cb7eb5210901c Mon Sep 17 00:00:00 2001
From: Bruno Bornsztein <bruno.bornsztein@gmail.com>
Date: Thu, 12 Feb 2026 06:45:30 -0600
Subject: [PATCH] Reduce GitHub API rate limit usage by 75%

Problem: The UI was polling GitHub every 15 seconds, making 3 API calls
per repository per poll (open, merged, and closed PRs). This resulted in
720 API calls per hour for a single repo, easily exceeding GitHub's rate
limits (5,000/hour authenticated, 60/hour unauthenticated).

Changes:
1. Increased PR refresh interval from 15s to 60s (4x reduction)
2. Increased cache TTL from 15s to 90s (6x increase)
3. Added rate limit error detection and graceful handling

Impact:
- API usage reduced from 720 calls/hour to 180 calls/hour (75% reduction)
- PR information still refreshes every minute (reasonable for CI checks)
- Cache now lasts longer than refresh interval, improving efficiency
- Rate limit errors are detected and handled gracefully

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
---
 internal/github/pr.go | 32 +++++++++++++++++++++++++++-----
 internal/ui/app.go    |  4 ++--
 2 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/internal/github/pr.go b/internal/github/pr.go
index 36fa418..292f696 100644
--- a/internal/github/pr.go
+++ b/internal/github/pr.go
@@ -75,7 +75,7 @@ type cacheEntry struct {
 	fetchedAt time.Time
 }
 
-const cacheTTL = 15 * time.Second
+const cacheTTL = 90 * time.Second
 
 // NewPRCache creates a new PR cache.
 func NewPRCache() *PRCache {
@@ -144,6 +144,14 @@ func fetchPRInfo(repoDir, branchName string) *PRInfo {
 
 	output, err := cmd.Output()
 	if err != nil {
+		// Check if this is a rate limit error
+		if exitErr, ok := err.(*exec.ExitError); ok {
+			stderr := string(exitErr.Stderr)
+			if strings.Contains(stderr, "rate limit") || strings.Contains(stderr, "API rate limit") {
+				// Return nil on rate limit (cache will be used if available)
+				return nil
+			}
+		}
 		// No PR exists for this branch, timeout, or other error
 		return nil
 	}
@@ -330,6 +338,14 @@ func FetchAllPRsForRepo(repoDir string) map[string]*PRInfo {
 
 	output, err := cmd.Output()
 	if err != nil {
+		// Check if this is a rate limit error
+		if exitErr, ok := err.(*exec.ExitError); ok {
+			stderr := string(exitErr.Stderr)
+			if strings.Contains(stderr, "rate limit") || strings.Contains(stderr, "API rate limit") {
+				// Return nil to signal rate limit hit (caller can use cached data)
+				return nil
+			}
+		}
 		return result
 	}
 
@@ -355,8 +371,8 @@ func FetchAllPRsForRepo(repoDir string) map[string]*PRInfo {
 		"--limit", "20")
 	cmd2.Dir = repoDir
 
-	output2, err := cmd2.Output()
-	if err == nil {
+	output2, err2 := cmd2.Output()
+	if err2 == nil {
 		var mergedPRs []ghPRListResponse
 		if json.Unmarshal(output2, &mergedPRs) == nil {
 			for _, pr := range mergedPRs {
@@ -369,6 +385,12 @@ func FetchAllPRsForRepo(repoDir string) map[string]*PRInfo {
 				}
 			}
 		}
+	} else if exitErr, ok := err2.(*exec.ExitError); ok {
+		stderr := string(exitErr.Stderr)
+		if strings.Contains(stderr, "rate limit") || strings.Contains(stderr, "API rate limit") {
+			// Hit rate limit, skip closed PR fetch too
+			return result
+		}
 	}
 
 	// Also fetch recently closed PRs (last 10) to catch closures
@@ -381,8 +403,8 @@ func FetchAllPRsForRepo(repoDir string) map[string]*PRInfo {
 		"--limit", "10")
 	cmd3.Dir = repoDir
 
-	output3, err := cmd3.Output()
-	if err == nil {
+	output3, err3 := cmd3.Output()
+	if err3 == nil {
 		var closedPRs []ghPRListResponse
 		if json.Unmarshal(output3, &closedPRs) == nil {
 			for _, pr := range closedPRs {
diff --git a/internal/ui/app.go b/internal/ui/app.go
index 002e78b..303843a 100644
--- a/internal/ui/app.go
+++ b/internal/ui/app.go
@@ -940,7 +940,7 @@ func (m *AppModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
 		}
 
 	case prRefreshTickMsg:
-		// Periodically refresh PR info (every 15 seconds)
+		// Periodically refresh PR info (every 60 seconds)
 		// Always refresh regardless of view - PR state is persisted to DB
 		// so it stays current even when navigating between views
 		cmds = append(cmds, m.refreshAllPRs())
@@ -4174,7 +4174,7 @@ func (m *AppModel) focusTick() tea.Cmd {
 }
 
 func (m *AppModel) prRefreshTick() tea.Cmd {
-	return tea.Tick(15*time.Second, func(t time.Time) tea.Msg {
+	return tea.Tick(60*time.Second, func(t time.Time) tea.Msg {
 		return prRefreshTickMsg(t)
 	})
 }