Add and use parseUserConfig

- Throws a `ConfigurationError` if parsing the YAML fails
- Add a couple of tests for it

lib/init-action.js

@@ -85319,6 +85319,7 @@ function renamed(from, to) {
 var load = loader.load;
 var loadAll = loader.loadAll;
 var dump = dumper.dump;
+var YAMLException = exception;
 var safeLoad = renamed("safeLoad", "load");
 var safeLoadAll = renamed("safeLoadAll", "loadAll");
 var safeDump = renamed("safeDump", "dump");
@@ -86310,6 +86311,9 @@ function getConfigFileOutsideWorkspaceErrorMessage(configFile) {
 function getConfigFileDoesNotExistErrorMessage(configFile) {
   return `The configuration file "${configFile}" does not exist`;
 }
+function getConfigFileParseErrorMessage(configFile, message) {
+  return `Cannot parse "${configFile}": ${message}`;
+}
 function getConfigFileRepoFormatInvalidMessage(configFile) {
   let error2 = `The configuration file "${configFile}" is not a supported remote file reference.`;
   error2 += " Expected format <owner>/<repository>/<file-path>@<ref>";
@@ -86601,6 +86605,18 @@ function generateCodeScanningConfig(logger, originalUserInput, augmentationPrope
   }
   return augmentedConfig;
 }
+function parseUserConfig(pathInput, contents) {
+  try {
+    return load(contents);
+  } catch (error2) {
+    if (error2 instanceof YAMLException) {
+      throw new ConfigurationError(
+        getConfigFileParseErrorMessage(pathInput, error2.message)
+      );
+    }
+    throw error2;
+  }
+}
 
 // src/feature-flags.ts
 var fs7 = __toESM(require("fs"));
@@ -88033,7 +88049,7 @@ function getLocalConfig(configFile) {
       getConfigFileDoesNotExistErrorMessage(configFile)
     );
   }
-  return load(fs9.readFileSync(configFile, "utf8"));
+  return parseUserConfig(configFile, fs9.readFileSync(configFile, "utf-8"));
 }
 async function getRemoteConfig(configFile, apiDetails) {
   const format = new RegExp(
@@ -88063,7 +88079,8 @@ async function getRemoteConfig(configFile, apiDetails) {
       getConfigFileFormatInvalidMessage(configFile)
     );
   }
-  return load(
+  return parseUserConfig(
+    configFile,
     Buffer.from(fileContents, "base64").toString("binary")
   );
 }