Override defaultSeverity of extended configs (palantir#2569).

docs/usage/configuration/index.md

@@ -30,7 +30,7 @@ A path to a directory or an array of paths to directories of [custom rules][2].
   - Any rules specified in this block will override those configured in any base configuration being extended.
   - [Check out the full rules list here][3].
 * `jsRules?: any`: Same format as `rules`. These rules are applied to `.js` and `.jsx` files.
-* `defaultSeverity?: "error" | "warning" | "off"`: The severity level used when a rule specifies a default warning level. If undefined, "error" is used. This value is not inherited and is only applied to rules in this file.
+* `defaultSeverity?: "error" | "warning" | "off"`: The severity level used when a rule specifies a default warning level. If undefined, "error" is used. If specified, overrides the values defined in the configuration files which are extended by this configuration.
 * `linterOptions?: { exclude?: string[] }`:
   - `exclude: string[]`: An array of globs. Any file matching these globs will not be linted. All exclude patterns are relative to the configuration file they were specified in.
 

src/configuration.ts

@@ -25,7 +25,7 @@ import { arrayify, hasOwnProperty, stripComments } from "./utils";
 
 export interface IConfigurationFile {
     /**
-     * The severity that is applied to rules in _this_ config with `severity === "default"`.
+     * The severity that is applied to rules in this and _extended_ configs with `severity === "default"`.
      * Not inherited.
      */
     defaultSeverity?: RuleSeverity;
@@ -200,9 +200,10 @@ function findup(filename: string, directory: string): string | undefined {
  * 'path/to/config' will attempt to load a to/config file inside a node module named path
  * @param configFilePath The configuration to load
  * @param originalFilePath The entry point configuration file
+ * @param extendingConfig The configuration which extends this one
  * @returns a configuration object for TSLint loaded from the file at configFilePath
  */
-export function loadConfigurationFromPath(configFilePath?: string, originalFilePath = configFilePath) {
+export function loadConfigurationFromPath(configFilePath?: string, originalFilePath = configFilePath, extendingConfig?: RawConfigFile) {
     if (configFilePath == undefined) {
         return DEFAULT_CONFIG;
     } else {
@@ -224,14 +225,19 @@ export function loadConfigurationFromPath(configFilePath?: string, originalFileP
             delete (require.cache as { [key: string]: any })[resolvedConfigFilePath];
         }
 
+        // defaultSeverity defined in the config which extends this one wins.
+        if (extendingConfig && extendingConfig.defaultSeverity) {
+            rawConfigFile.defaultSeverity = extendingConfig.defaultSeverity;
+        }
+
         const configFileDir = path.dirname(resolvedConfigFilePath);
         const configFile = parseConfigFile(rawConfigFile, configFileDir);
 
         // load configurations, in order, using their identifiers or relative paths
         // apply the current configuration last by placing it last in this array
         const configs: IConfigurationFile[] = configFile.extends.map((name) => {
             const nextConfigFilePath = resolveConfigurationPath(name, configFileDir);
-            return loadConfigurationFromPath(nextConfigFilePath, originalFilePath);
+            return loadConfigurationFromPath(nextConfigFilePath, originalFilePath, rawConfigFile);
         }).concat([configFile]);
 
         return configs.reduce(extendConfigurationFile, EMPTY_CONFIG);

test/config/tslint-default-severity-error.json

@@ -0,0 +1,6 @@
+{
+  "defaultSeverity": "error",
+  "rules": {
+    "default-severity-error": { "severity": "default" }
+  }
+}

test/config/tslint-default-severity-unspecified.json

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "default-severity-unspecified": { "severity": "default" }
+  }
+}

test/config/tslint-extends-default-severity.json

@@ -0,0 +1,7 @@
+{
+  "extends": [ "./tslint-default-severity-unspecified.json", "./tslint-default-severity-error.json" ],
+  "defaultSeverity": "warning",
+  "rules": {
+    "default-severity-warning": { "severity": "default" }
+  }
+}

test/configurationTests.ts

@@ -251,6 +251,22 @@ describe("Configuration", () => {
             const actualConfig = extendConfigurationFile(baseConfig, extendingConfig);
             assertConfigEquals(actualConfig, expectedConfig);
         });
+
+        it("overrides defaultSeverity of base configs", () => {
+            const config = loadConfigurationFromPath("./test/config/tslint-extends-default-severity.json");
+            assert.equal<RuleSeverity | undefined>(
+                "warning",
+                config.rules.get("default-severity-unspecified")!.ruleSeverity,
+                "did not apply defaultSeverity to base config with no defaultSeverity");
+            assert.equal<RuleSeverity | undefined>(
+                "warning",
+                config.rules.get("default-severity-error")!.ruleSeverity,
+                "did not override defaultSeverity defined in base config");
+            assert.equal<RuleSeverity | undefined>(
+                "warning",
+                config.rules.get("default-severity-warning")!.ruleSeverity,
+                "did not apply defaultSeverity to extending config");
+        });
     });
 
     describe("findConfigurationPath", () => {