fix: report syntax error instead of throw (#272)

package.json

@@ -28,6 +28,7 @@
   },
   "dependencies": {
     "eslint-plugin-prettier": "^2.2.0",
+    "lines-and-columns": "^1.1.6",
     "tslib": "^1.7.1"
   },
   "devDependencies": {

src/prettierRule.ts

@@ -1,4 +1,5 @@
 import * as utils from 'eslint-plugin-prettier';
+import LineAndColumn from 'lines-and-columns';
 import * as path from 'path';
 import * as prettier from 'prettier';
 import * as tslint from 'tslint';
@@ -60,19 +61,45 @@ class Walker extends tslint.AbstractWalker<any[]> {
     }
 
     const source = sourceFile.getFullText();
-    const formatted = prettier.format(source, {
-      parser: 'typescript',
-      ...options,
-    });
 
-    if (source === formatted) {
-      return;
-    }
+    try {
+      const formatted = prettier.format(source, {
+        parser: 'typescript',
+        ...options,
+      });
+
+      if (source === formatted) {
+        return;
+      }
 
-    reportDifferences(this, source, formatted);
+      reportDifferences(this, source, formatted);
+    } catch (e) {
+      // istanbul ignore else
+      if (e.loc) {
+        reportSyntaxError(this, source, e);
+      } else {
+        throw e;
+      }
+    }
   }
 }
 
+function reportSyntaxError(
+  walkContext: tslint.WalkContext<any>,
+  source: string,
+  error: { message: string; loc: { start: { line: number; column: number } } },
+) {
+  const locator = new LineAndColumn(source);
+  const offset = locator.indexForLocation({
+    column: error.loc.start.column - 1,
+    line: error.loc.start.line - 1,
+  })!;
+  const message = error.message
+    .split('\n')[0]
+    .replace(/\s*\(\d+:\d+\)\s*$/, '');
+  walkContext.addFailureAt(offset, 1, `SyntaxError: ${message}`);
+}
+
 function reportDifferences(
   walkContext: tslint.WalkContext<any>,
   source: string,

tests/prettier/default/syntax-error.ts.lint

@@ -0,0 +1,2 @@
+hello world
+      ~ [SyntaxError: ';' expected.]

yarn.lock

@@ -1294,6 +1294,10 @@ lcid@^1.0.0:
   dependencies:
     invert-kv "^1.0.0"
 
+lines-and-columns@^1.1.6:
+  version "1.1.6"
+  resolved "https://registry.yarnpkg.com/lines-and-columns/-/lines-and-columns-1.1.6.tgz#1c00c743b433cd0a4e80758f7b64a57440d9ff00"
+
 load-json-file@^1.0.0:
   version "1.1.0"
   resolved "http://registry.npmjs.org/load-json-file/-/load-json-file-1.1.0.tgz#956905708d58b4bab4c2261b04f59f31c99374c0"