fix(cli/rt/error_stack): Improve message line formatting (#7860)

2 files changed, 41 insertions, 3 deletions

diff --git a/cli/tests/error_014_catch_dynamic_import_error.js.out b/cli/tests/error_014_catch_dynamic_import_error.js.out
index 5249425b3..5ec98df02 100644
--- a/cli/tests/error_014_catch_dynamic_import_error.js.out
+++ b/cli/tests/error_014_catch_dynamic_import_error.js.out
@@ -1,9 +1,7 @@
 Caught direct dynamic import error.
 TypeError: relative import path "does not exist" not prefixed with / or ./ or ../ Imported from "[WILDCARD]/error_014_catch_dynamic_import_error.js"
-
 Caught indirect direct dynamic import error.
 TypeError: relative import path "does not exist either" not prefixed with / or ./ or ../ Imported from "[WILDCARD]/indirect_import_error.js"
-
 Caught error thrown by dynamically imported module.
 Error: An error
     at file:///[WILDCARD]tests/subdir/throws.js:6:7
diff --git a/cli/tests/unit/error_stack_test.ts b/cli/tests/unit/error_stack_test.ts
index 50cc2493b..d795a2951 100644
--- a/cli/tests/unit/error_stack_test.ts
+++ b/cli/tests/unit/error_stack_test.ts
@@ -1,5 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-import { assert, assertEquals, unitTest } from "./test_util.ts";
+import { assert, assertEquals, assertMatch, unitTest } from "./test_util.ts";
 
 // @ts-expect-error TypeScript (as of 3.7) does not support indexing namespaces by symbol
 const { setPrepareStackTrace } = Deno[Deno.internal];
@@ -82,6 +82,46 @@ function getMockCallSite(
   };
 }
 
+unitTest(function errorStackMessageLine(): void {
+  const e1 = new Error();
+  e1.name = "Foo";
+  e1.message = "bar";
+  assertMatch(e1.stack!, /^Foo: bar\n/);
+
+  const e2 = new Error();
+  e2.name = "";
+  e2.message = "bar";
+  assertMatch(e2.stack!, /^bar\n/);
+
+  const e3 = new Error();
+  e3.name = "Foo";
+  e3.message = "";
+  assertMatch(e3.stack!, /^Foo\n/);
+
+  const e4 = new Error();
+  e4.name = "";
+  e4.message = "";
+  assertMatch(e4.stack!, /^\n/);
+
+  const e5 = new Error();
+  // deno-lint-ignore ban-ts-comment
+  // @ts-expect-error
+  e5.name = undefined;
+  // deno-lint-ignore ban-ts-comment
+  // @ts-expect-error
+  e5.message = undefined;
+  assertMatch(e5.stack!, /^Error\n/);
+
+  const e6 = new Error();
+  // deno-lint-ignore ban-ts-comment
+  // @ts-expect-error
+  e6.name = null;
+  // deno-lint-ignore ban-ts-comment
+  // @ts-expect-error
+  e6.message = null;
+  assertMatch(e6.stack!, /^null: null\n/);
+});
+
 // FIXME(bartlomieju): no longer works after migrating
 // to JavaScript runtime code
 unitTest({ ignore: true }, function prepareStackTrace(): void {