fix(lint): remove unused function and fix unchecked error returns

- Remove unused getEnvOrDefault function
- Add blank identifier assignments for unchecked error returns in test file

Co-authored-by: Ona <[email protected]>

Author: leodido

pkg/leeway/signing/attestation.go

@@ -426,11 +426,3 @@ func fetchGitHubOIDCToken(ctx context.Context, audience string) (string, error)
 
 	return payload.Value, nil
 }
-
-// getEnvOrDefault returns environment variable value or default
-func getEnvOrDefault(key, defaultValue string) string {
-	if value := os.Getenv(key); value != "" {
-		return value
-	}
-	return defaultValue
-}

pkg/leeway/signing/attestation_test.go

@@ -1117,7 +1117,7 @@ func TestFetchGitHubOIDCToken(t *testing.T) {
 						t.Error("Missing or invalid Authorization header")
 					}
 					w.WriteHeader(http.StatusOK)
-					json.NewEncoder(w).Encode(map[string]string{"value": "test-token-12345"})
+					_ = json.NewEncoder(w).Encode(map[string]string{"value": "test-token-12345"})
 				}))
 			},
 			audience:    "sigstore",
@@ -1138,7 +1138,7 @@ func TestFetchGitHubOIDCToken(t *testing.T) {
 			mockServer: func(t *testing.T) *httptest.Server {
 				return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 					w.WriteHeader(http.StatusInternalServerError)
-					w.Write([]byte(`{"error": "internal error"}`))
+					_, _ = w.Write([]byte(`{"error": "internal error"}`))
 				}))
 			},
 			audience:      "sigstore",
@@ -1150,7 +1150,7 @@ func TestFetchGitHubOIDCToken(t *testing.T) {
 			mockServer: func(t *testing.T) *httptest.Server {
 				return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 					w.WriteHeader(http.StatusOK)
-					json.NewEncoder(w).Encode(map[string]string{"value": ""})
+					_ = json.NewEncoder(w).Encode(map[string]string{"value": ""})
 				}))
 			},
 			audience:      "sigstore",
@@ -1162,7 +1162,7 @@ func TestFetchGitHubOIDCToken(t *testing.T) {
 			mockServer: func(t *testing.T) *httptest.Server {
 				return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 					w.WriteHeader(http.StatusOK)
-					w.Write([]byte(`invalid json`))
+					_, _ = w.Write([]byte(`invalid json`))
 				}))
 			},
 			audience:      "sigstore",