give better error messages

lib/config-utils.js

@@ -105,6 +105,24 @@ class Config {
     }
 }
 exports.Config = Config;
+// Regex validating stars in paths or paths-ignore entries.
+// The intention is to only allow ** to appear when immediately
+// preceded and followed by a slash.
+const pathStarsRegex = /.*(?:\*\*[^/].*|\*\*$|[^/]\*\*.*)/;
+// Checks that a paths of paths-ignore entry is valid, possibly modifying it
+// to make it valid, or if not possible then throws an error.
+function validateAndSanitisePath(originalPath, propertyName, configFile) {
+    let path = originalPath;
+    if (path.endsWith('/**')) {
+        path = path.substring(0, path.length - 2);
+    }
+    if (path.match(pathStarsRegex)) {
+        throw new Error(getConfigFilePropertyError(configFile, propertyName, '"' + originalPath + '" contains an invalid "**" wildcard. ' +
+            'They must be immediately preceeded and followed by a slash as in "/**/".'));
+    }
+    return path;
+}
+exports.validateAndSanitisePath = validateAndSanitisePath;
 function getNameInvalid(configFile) {
     return getConfigFilePropertyError(configFile, NAME_PROPERTY, 'must be a non-empty string');
 }
@@ -216,7 +234,7 @@ async function initConfig() {
             if (typeof path !== "string" || path === '') {
                 throw new Error(getPathsIgnoreInvalid(configFile));
             }
-            config.pathsIgnore.push(path);
+            config.pathsIgnore.push(validateAndSanitisePath(path, PATHS_IGNORE_PROPERTY, configFile));
         });
     }
     if (PATHS_PROPERTY in parsedYAML) {
@@ -227,7 +245,7 @@ async function initConfig() {
             if (typeof path !== "string" || path === '') {
                 throw new Error(getPathsInvalid(configFile));
             }
-            config.paths.push(path);
+            config.paths.push(validateAndSanitisePath(path, PATHS_PROPERTY, configFile));
         });
     }
     return config;