module: fix column offsets in errors

Because Node modules are wrapped, errors on the first line
of a file leak the wrapper to the user and report the wrong
column number. This commit adds a line break to the module
wrapper so that the first line is treated the same as all
other lines. To compensate for the additional line, a line
offset of -1 is also applied to errors.

Fixes: https://github.com/nodejs/node/issues/2860
PR-URL: https://github.com/nodejs/node/pull/2867
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

3 files changed, 21 insertions, 0 deletions

diff --git a/test/fixtures/test-error-first-line-offset.js b/test/fixtures/test-error-first-line-offset.js
new file mode 100644
index 0000000000..9aeeab047d
--- /dev/null
+++ b/test/fixtures/test-error-first-line-offset.js
@@ -0,0 +1 @@
+error

diff --git a/test/parallel/test-vm-context.js b/test/parallel/test-vm-context.js
index 45e19e6638..e1cd2ef01e 100644
--- a/test/parallel/test-vm-context.js
+++ b/test/parallel/test-vm-context.js
@@ -60,3 +60,15 @@ var ctx = {};
 Object.defineProperty(ctx, 'b', { configurable: false });
 ctx = vm.createContext(ctx);
 assert.equal(script.runInContext(ctx), false);
+
+// Error on the first line of a module should
+// have the correct line and column number
+assert.throws(function() {
+  vm.runInContext('throw new Error()', context, {
+    filename: 'expected-filename.js',
+    lineOffset: 32,
+    columnOffset: 123
+  });
+}, function(err) {
+  return /expected-filename.js:33:130/.test(err.stack);
+}, 'Expected appearance of proper offset in Error stack');
diff --git a/test/sequential/test-module-loading.js b/test/sequential/test-module-loading.js
index d53de512f2..a8696f84cd 100644
--- a/test/sequential/test-module-loading.js
+++ b/test/sequential/test-module-loading.js
@@ -279,3 +279,11 @@ process.on('exit', function() {
 // #1440 Loading files with a byte order marker.
 assert.equal(42, require('../fixtures/utf8-bom.js'));
 assert.equal(42, require('../fixtures/utf8-bom.json'));
+
+// Error on the first line of a module should
+// have the correct line and column number
+assert.throws(function() {
+  require('../fixtures/test-error-first-line-offset.js');
+}, function(err) {
+  return /test-error-first-line-offset.js:1:1/.test(err.stack);
+}, 'Expected appearance of proper offset in Error stack');