fix: Do not write an empty file when using --json-file-output [CLI-11…

…5] (#5030)

src/cli/main.ts

@@ -459,7 +459,7 @@ async function saveResultsToFile(
 ) {
   const flag = `${outputType}-file-output`;
   const outputFile = options[flag];
-  if (outputFile && (jsonResults || jsonPayload)) {
+  if (outputFile && (jsonResults || !isEmpty(jsonPayload))) {
     const outputFileStr = outputFile as string;
     const fullOutputFilePath = getFullPath(outputFileStr);
     await saveJsonResultsToFile(

test/acceptance/workspaces/golang-gomodules/main.go

@@ -0,0 +1,5 @@
+package main
+
+func main() {
+	// nothing to see here
+}

test/jest/acceptance/cli-json-file-output.spec.ts

@@ -146,4 +146,17 @@ describe('test --json-file-output', () => {
     });
     expect(fileSize).toBeGreaterThan(500000000); // ~0.5GB
   }, 120000);
+
+  it('test --json-file-ouput does not write an empty file if no issues are found', async () => {
+    const project = await createProjectFromWorkspace('golang-gomodules');
+    const outputFilename = project.path() + '/shouldnt_be_there.json';
+
+    const { code } = await runSnykCLI(
+      `code test --json-file-output=${outputFilename} ${project.path()}`,
+    );
+
+    const fileExists = fs.existsSync(outputFilename);
+    expect(fileExists).toBeFalsy();
+    expect(code).toEqual(0);
+  });
 });