fix(network): classify timeout errors as FailoverTimeout

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

pkg/providers/error_classifier.go

@@ -226,12 +226,18 @@ func classifyByErrorType(err error) FailoverReason {
 		syscall.EPIPE,
 	} {
 		if errors.Is(err, transportErr) {
+			if transportErr == syscall.ETIMEDOUT {
+				return FailoverTimeout
+			}
 			return FailoverNetwork
 		}
 	}
 
 	var netErr net.Error
 	if errors.As(err, &netErr) {
+		if netErr.Timeout() {
+			return FailoverTimeout
+		}
 		return FailoverNetwork
 	}
 

pkg/providers/error_classifier_test.go

@@ -7,9 +7,19 @@ import (
 	"io"
 	"net"
 	"net/url"
+	"syscall"
 	"testing"
 )
 
+type stubNetError struct {
+	msg     string
+	timeout bool
+}
+
+func (e stubNetError) Error() string   { return e.msg }
+func (e stubNetError) Timeout() bool   { return e.timeout }
+func (e stubNetError) Temporary() bool { return false }
+
 func TestClassifyError_Nil(t *testing.T) {
 	result := ClassifyError(nil, "openai", "gpt-4")
 	if result != nil {
@@ -216,6 +226,57 @@ func TestClassifyError_NetworkTypes(t *testing.T) {
 	}
 }
 
+func TestClassifyError_TimeoutNetworkTypes(t *testing.T) {
+	tests := []struct {
+		name string
+		err  error
+	}{
+		{
+			name: "wrapped syscall timeout",
+			err:  fmt.Errorf("dial tcp: %w", syscall.ETIMEDOUT),
+		},
+		{
+			name: "net error timeout",
+			err: &url.Error{
+				Op:  "Post",
+				URL: "https://example.com",
+				Err: stubNetError{msg: "i/o timeout", timeout: true},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := ClassifyError(tt.err, "openai", "gpt-4")
+			if result == nil {
+				t.Fatal("expected non-nil")
+			}
+			if result.Reason != FailoverTimeout {
+				t.Fatalf("reason = %q, want timeout", result.Reason)
+			}
+		})
+	}
+}
+
+func TestClassifyError_TimeoutPatternsWinOverNetworkContext(t *testing.T) {
+	patterns := []string{
+		`failed to send request: Post "https://example.com": dial tcp 203.0.113.10:443: i/o timeout`,
+		`read tcp 10.20.0.1:61279->172.65.90.20:443: i/o timeout`,
+	}
+
+	for _, msg := range patterns {
+		err := errors.New(msg)
+		result := ClassifyError(err, "openai", "gpt-4")
+		if result == nil {
+			t.Errorf("pattern %q: expected non-nil", msg)
+			continue
+		}
+		if result.Reason != FailoverTimeout {
+			t.Errorf("pattern %q: reason = %q, want timeout", msg, result.Reason)
+		}
+	}
+}
+
 func TestClassifyError_NetworkPatternsWinOverAuthExpired(t *testing.T) {
 	err := errors.New(
 		`Post "https://example.com": tls: failed to verify certificate: x509: certificate has expired or is not yet valid`,

pkg/providers/fallback_test.go

@@ -306,6 +306,42 @@ func TestFallback_NetworkErrorFallsBack(t *testing.T) {
 	}
 }
 
+func TestFallback_TimeoutErrorFallsBack(t *testing.T) {
+	ct := NewCooldownTracker()
+	fc := NewFallbackChain(ct, nil)
+
+	candidates := []FallbackCandidate{
+		makeCandidate("openai", "gpt-4"),
+		makeCandidate("anthropic", "claude"),
+	}
+
+	attempt := 0
+	run := func(ctx context.Context, provider, model string) (*LLMResponse, error) {
+		attempt++
+		if attempt == 1 {
+			return nil, errors.New("failed to send request: Post \"https://example.com\": i/o timeout")
+		}
+		return &LLMResponse{Content: "timeout fallback ok", FinishReason: "stop"}, nil
+	}
+
+	result, err := fc.Execute(context.Background(), candidates, run)
+	if err != nil {
+		t.Fatalf("expected fallback success, got error: %v", err)
+	}
+	if attempt != 2 {
+		t.Fatalf("attempt = %d, want 2", attempt)
+	}
+	if result.Provider != "anthropic" || result.Model != "claude" {
+		t.Fatalf("result = %s/%s, want anthropic/claude", result.Provider, result.Model)
+	}
+	if len(result.Attempts) != 1 {
+		t.Fatalf("attempts = %d, want 1 failed attempt recorded", len(result.Attempts))
+	}
+	if result.Attempts[0].Reason != FailoverTimeout {
+		t.Fatalf("attempt reason = %q, want timeout", result.Attempts[0].Reason)
+	}
+}
+
 func TestFallback_SuccessResetsCooldown(t *testing.T) {
 	ct := NewCooldownTracker()
 	fc := NewFallbackChain(ct, nil)