feat: support error cause (#1012)

Author: waltjones

src/browser/transforms.js

@@ -42,8 +42,8 @@ function addErrorContext(item) {
 
   chain.push(err);
 
-  while (err.nested) {
-    err = err.nested;
+  while (err.nested || err.cause) {
+    err = err.nested || err.cause;
     chain.push(err);
   }
 

src/errorParser.js

@@ -64,11 +64,11 @@ function Stack(exception, skip) {
 function parse(e, skip) {
   var err = e;
 
-  if (err.nested) {
+  if (err.nested || err.cause) {
     var traceChain = [];
     while (err) {
       traceChain.push(new Stack(err, skip));
-      err = err.nested;
+      err = err.nested || err.cause;
 
       skip = 0; // Only apply skip value to primary error
     }

src/server/transforms.js

@@ -85,7 +85,7 @@ function handleItemWithError(item, options, callback) {
   var chain = [];
   do {
     errors.push(err);
-    err = err.nested;
+    err = err.nested || err.cause;
   } while (err);
   item.stackInfo = chain;
 

test/browser.transforms.test.js

@@ -30,6 +30,10 @@ function itemFromArgs(args) {
   return item;
 }
 
+function chromeMajorVersion() {
+  return parseInt(navigator.userAgent.match(/Chrome\/([0-9]+)\./)[1]);
+}
+
 describe('handleDomException', function() {
   it('should do nothing if not a DOMException', function(done) {
     var err = new Error('test');
@@ -452,6 +456,45 @@ describe('addBody', function() {
       });
     });
   });
+  describe('with error cause', function() {
+    // Error cause was introduced in Chrome 93.
+    if (chromeMajorVersion() < 93) return;
+
+    it('should create trace_chain', function(done) {
+      var causeErr = new Error('cause error');
+      var err = new Error('test error', { cause: causeErr});
+      var args = ['a message', err];
+      var item = itemFromArgs(args);
+      var options = {};
+      t.handleItemWithError(item, options, function(e, i) {
+        expect(i.stackInfo).to.be.ok();
+      });
+      t.addBody(item, options, function(e, i) {
+        expect(i.data.body.trace_chain.length).to.eql(2);
+        expect(i.data.body.trace_chain[0].exception.message).to.eql('test error');
+        expect(i.data.body.trace_chain[1].exception.message).to.eql('cause error');
+        done(e);
+      });
+    });
+    it('should create add error context as custom data', function(done) {
+      var causeErr = new Error('cause error');
+      causeErr.rollbarContext = { err1: 'cause context' };
+      var err = new Error('test error', { cause: causeErr});
+      err.rollbarContext = { err2: 'error context' };
+      var args = ['a message', err];
+      var item = itemFromArgs(args);
+      var options = { addErrorContext: true };
+      t.handleItemWithError(item, options, function(e, i) {
+        expect(i.stackInfo).to.be.ok();
+      });
+      t.addBody(item, options, function(e, i) {
+        expect(i.data.body.trace_chain.length).to.eql(2);
+        expect(i.data.custom.err1).to.eql('cause context');
+        expect(i.data.custom.err2).to.eql('error context');
+        done(e);
+      });
+    });
+  });
 });
 
 describe('scrubPayload', function() {

test/server.transforms.test.js

@@ -30,6 +30,22 @@ async function throwInScriptFile(rollbar, filepath, callback) {
   callback(rollbar);
 }
 
+var nodeVersion = function () {
+  var version = process.versions.node.split('.');
+
+  return [
+    parseInt(version[0]),
+    parseInt(version[1]),
+    parseInt(version[2]),
+  ];
+}();
+
+var isMinNodeVersion = function(major, minor) {
+  return (
+    nodeVersion[0] > major || (nodeVersion[0] === major && nodeVersion[1] >= minor)
+  );
+}
+
 vows.describe('transforms')
   .addBatch({
     'baseData': {
@@ -494,7 +510,42 @@ vows.describe('transforms')
                 assert.equal(item.data.custom.err1, 'nested context');
                 assert.equal(item.data.custom.err2, 'error context');
               }
-            }
+            },
+            'with an error cause': {
+              topic: function (options) {
+                var test = function() {
+                  var x = thisVariableIsNotDefined;
+                };
+                var err;
+                try {
+                  test();
+                } catch (e) {
+                  err = new Error('cause message', { cause: e });
+                  e.rollbarContext = { err1: 'cause context' };
+                  err.rollbarContext = { err2: 'error context' };
+                }
+                var item = {
+                  data: {body: {}},
+                  err: err
+                };
+                t.handleItemWithError(item, options, this.callback);
+              },
+              'should not error': function(err, item) {
+                assert.ifError(err);
+              },
+              'should have the right data in the trace_chain': function(err, item) {
+                // Error cause was introduced in Node 16.9.
+                if (!isMinNodeVersion(16, 9)) return;
+
+                var trace_chain = item.stackInfo;
+                assert.lengthOf(trace_chain, 2);
+                assert.equal(trace_chain[0].exception.class, 'Error');
+                assert.equal(trace_chain[0].exception.message, 'cause message');
+                assert.equal(trace_chain[1].exception.class, 'ReferenceError');
+                assert.equal(item.data.custom.err1, 'cause context');
+                assert.equal(item.data.custom.err2, 'error context');
+              }
+            },
           }
         }
       }