Fix: Remove duplicate error message on crash (fixes #8964) (#10865)

Author: nzakas

bin/eslint.js

@@ -48,7 +48,6 @@ process.once("uncaughtException", err => {
         console.error(`\nESLint: ${pkg.version}.\n${template(err.messageData || {})}`);
     } else {
 
-        console.error(err.message);
         console.error(err.stack);
     }
 

tests/bin/eslint.js

@@ -333,12 +333,28 @@ describe("bin/eslint.js", () => {
             return Promise.all([exitCodeAssertion, outputAssertion]);
         });
 
+        it("prints the error message exactly once to stderr in the event of a crash", () => {
+            const child = runESLint(["--rule=no-restricted-syntax:[error, 'Invalid Selector [[[']", "Makefile.js"]);
+            const exitCodeAssertion = assertExitCode(child, 2);
+            const outputAssertion = getOutput(child).then(output => {
+                const expectedSubstring = "Syntax error in selector";
+
+                assert.strictEqual(output.stdout, "");
+                assert.include(output.stderr, expectedSubstring);
+
+                // The message should appear exactly once in stderr
+                assert.strictEqual(output.stderr.indexOf(expectedSubstring), output.stderr.lastIndexOf(expectedSubstring));
+            });
+
+            return Promise.all([exitCodeAssertion, outputAssertion]);
+        });
+
         it("prints the error message pointing to line of code", () => {
             const invalidConfig = `${__dirname}/../fixtures/bin/.eslintrc.yml`;
             const child = runESLint(["--no-ignore", invalidConfig]);
             const exitCodeAssertion = assertExitCode(child, 2);
             const outputAssertion = getOutput(child).then(output => {
-                const expectedSubstring = "Error: bad indentation of a mapping entry at line";
+                const expectedSubstring = ": bad indentation of a mapping entry at line";
 
                 assert.strictEqual(output.stdout, "");
                 assert.include(output.stderr, expectedSubstring);