Include inner exceptions in stack traces

lib/jasmine-core/jasmine.js

@@ -3494,18 +3494,38 @@ getJasmineRequireObj().ExceptionFormatter = function(j$) {
         return null;
       }
 
-      const stackTrace = new j$.StackTrace(error);
-      const lines = filterJasmine(stackTrace);
-      let result = '';
+      const lines = this.stack_(error, {
+        messageHandling: omitMessage ? 'omit' : undefined
+      });
+      return lines.join('\n');
+    };
 
-      if (stackTrace.message && !omitMessage) {
+    // messageHandling can be falsy (unspecified), 'omit', or 'require'
+    this.stack_ = function(error, { messageHandling }) {
+      let lines = formatProperties(error).split('\n');
+
+      if (lines[lines.length - 1] === '') {
+        lines.pop();
+      }
+
+      const stackTrace = new j$.StackTrace(error);
+      lines = lines.concat(filterJasmine(stackTrace));
+
+      if (messageHandling === 'require') {
+        lines.unshift(stackTrace.message || 'Error: ' + error.message);
+      } else if (messageHandling !== 'omit' && stackTrace.message) {
         lines.unshift(stackTrace.message);
       }
 
-      result += formatProperties(error);
-      result += lines.join('\n');
+      if (error.cause) {
+        const substack = this.stack_(error.cause, {
+          messageHandling: 'require'
+        });
+        substack[0] = 'Caused by: ' + substack[0];
+        lines = lines.concat(substack);
+      }
 
-      return result;
+      return lines;
     };
 
     function filterJasmine(stackTrace) {

spec/core/ExceptionFormatterSpec.js

@@ -256,5 +256,51 @@ describe('ExceptionFormatter', function() {
         expect(result).not.toContain('an error');
       });
     });
+
+    describe('In environments that support the cause property of Errors', function() {
+      beforeEach(function() {
+        const inner = new Error('inner');
+        const outer = new Error('outer', { cause: inner });
+
+        if (!outer.cause) {
+          // Currently: Node 12, Node 14, Safari 14
+          pending('Environment does not support error cause');
+        }
+      });
+
+      it('recursively includes the cause in the stack trace in this environment', function() {
+        const subject = new jasmineUnderTest.ExceptionFormatter();
+        const rootCause = new Error('root cause');
+        const proximateCause = new Error('proximate cause', {
+          cause: rootCause
+        });
+        const symptom = new Error('symptom', { cause: proximateCause });
+
+        const lines = subject.stack(symptom).split('\n');
+        // Not all environments include the message in the stack trace.
+        const hasRootMessage = lines[0].indexOf('symptom') !== -1;
+        const firstSymptomStackIx = hasRootMessage ? 1 : 0;
+
+        expect(lines[firstSymptomStackIx])
+          .withContext('first symptom stack frame')
+          .toContain('ExceptionFormatterSpec.js');
+        const proximateCauseMsgIx = lines.indexOf(
+          'Caused by: Error: proximate cause'
+        );
+        expect(proximateCauseMsgIx)
+          .withContext('index of proximate cause message')
+          .toBeGreaterThan(firstSymptomStackIx);
+        expect(lines[proximateCauseMsgIx + 1])
+          .withContext('first proximate cause stack frame')
+          .toContain('ExceptionFormatterSpec.js');
+        const rootCauseMsgIx = lines.indexOf('Caused by: Error: root cause');
+        expect(rootCauseMsgIx)
+          .withContext('index of root cause message')
+          .toBeGreaterThan(proximateCauseMsgIx + 1);
+        expect(lines[rootCauseMsgIx + 1])
+          .withContext('first root cause stack frame')
+          .toContain('ExceptionFormatterSpec.js');
+      });
+    });
   });
 });

src/core/ExceptionFormatter.js

@@ -44,18 +44,38 @@ getJasmineRequireObj().ExceptionFormatter = function(j$) {
         return null;
       }
 
-      const stackTrace = new j$.StackTrace(error);
-      const lines = filterJasmine(stackTrace);
-      let result = '';
+      const lines = this.stack_(error, {
+        messageHandling: omitMessage ? 'omit' : undefined
+      });
+      return lines.join('\n');
+    };
 
-      if (stackTrace.message && !omitMessage) {
+    // messageHandling can be falsy (unspecified), 'omit', or 'require'
+    this.stack_ = function(error, { messageHandling }) {
+      let lines = formatProperties(error).split('\n');
+
+      if (lines[lines.length - 1] === '') {
+        lines.pop();
+      }
+
+      const stackTrace = new j$.StackTrace(error);
+      lines = lines.concat(filterJasmine(stackTrace));
+
+      if (messageHandling === 'require') {
+        lines.unshift(stackTrace.message || 'Error: ' + error.message);
+      } else if (messageHandling !== 'omit' && stackTrace.message) {
         lines.unshift(stackTrace.message);
       }
 
-      result += formatProperties(error);
-      result += lines.join('\n');
+      if (error.cause) {
+        const substack = this.stack_(error.cause, {
+          messageHandling: 'require'
+        });
+        substack[0] = 'Caused by: ' + substack[0];
+        lines = lines.concat(substack);
+      }
 
-      return result;
+      return lines;
     };
 
     function filterJasmine(stackTrace) {