update grammar: improve reporting of exceeded github rate limit

build/npm/update-grammar.js

@@ -37,6 +37,10 @@ function download(url, redirectCount) {
 			response.on('data', function (data) {
 				content += data.toString();
 			}).on('end', function () {
+				if (response.statusCode === 403 && response.headers['x-ratelimit-remaining'] === '0') {
+					e('GitHub API rate exceeded. Set GITHUB_TOKEN environment variable to increase rate limit.');
+					return;
+				}
 				let count = redirectCount || 0;
 				if (count < 5 && response.statusCode >= 300 && response.statusCode <= 303 || response.statusCode === 307) {
 					let location = response.headers['location'];
@@ -64,12 +68,8 @@ function getCommitSha(repoId, repoPath) {
 				commitDate: lastCommit.commit.author.date
 			});
 		} catch (e) {
-			console.error("Failed extracting the SHA: " + content);
-			return Promise.resolve(null);
+			return Promise.reject(new Error("Failed extracting the SHA: " + content));
 		}
-	}, function () {
-		console.error('Failed loading ' + commitInfo);
-		return Promise.resolve(null);
 	});
 }
 
@@ -86,8 +86,7 @@ exports.update = function (repoId, repoPath, dest, modifyGrammar, version = 'mas
 		} else if (ext === '.json') {
 			grammar = JSON.parse(content);
 		} else {
-			console.error('Unknown file extension: ' + ext);
-			return;
+			return Promise.reject(new Error(('Unknown file extension: ' + ext)));
 		}
 		if (modifyGrammar) {
 			modifyGrammar(grammar);
@@ -118,11 +117,14 @@ exports.update = function (repoId, repoPath, dest, modifyGrammar, version = 'mas
 					console.log('Updated ' + path.basename(dest));
 				}
 			} catch (e) {
-				console.error(e);
+				return Promise.reject(e);
 			}
 		});
 
-	}, console.error);
+	}, console.error).catch(e => {
+		console.error(e);
+		process.exit(1);
+	});
 };
 
 if (path.basename(process.argv[1]) === 'update-grammar.js') {