add example regex match for stdout/err string

lib/exec_wrapper.js

@@ -37,12 +37,27 @@ async function exec_wrapper(commandLine, args, options) {
             }
         }
     };
-    const returnCode = await exec.exec(commandLine, args, {
-        listeners: listeners,
-        ...options
-    });
-    if (stderr === stdout) {
-        console.log('foo bar');
+    let returnCode;
+    try {
+        returnCode = await exec.exec(commandLine, args, {
+            listeners: listeners,
+            ...options
+        });
+    }
+    catch (e) {
+        returnCode = 1;
+    }
+    if (returnCode === 0) {
+        throw new Error('The exit code was ' + returnCode + '?!');
+    }
+    const regex = new RegExp("(No source code was seen during the build\\.|No JavaScript or TypeScript code found\\.)");
+    if (regex.test(stderr) || regex.test(stdout)) {
+        throw new Error(`No source code was found. This can occur if the specified build commands failed to compile or process any code.
+    - Confirm that there is some source code for the specified language in the project.
+    - For codebases written in Go, JavaScript, TypeScript, and Python, do not specify
+      an explicit --command.
+    - For other languages, the --command must specify a "clean" build which compiles
+    https://docs.github.com/en/github/finding-security-vulnerabilities-and-errors-in-your-code/configuring-code-scanning`);
     }
     return returnCode;
 }