Defer language aliasing to CLI when appropriate

src/codeql.ts

@@ -128,7 +128,7 @@ export interface CodeQL {
    */
   resolveBuildEnvironment(
     workingDir: string | undefined,
-    language: Language,
+    language: string,
   ): Promise<ResolveBuildEnvironmentOutput>;
 
   /**
@@ -780,7 +780,7 @@ export async function getCodeQLForCmd(
     },
     async resolveBuildEnvironment(
       workingDir: string | undefined,
-      language: Language,
+      language: string,
     ) {
       const codeqlArgs = [
         "resolve",

src/resolve-environment-action.ts

@@ -8,7 +8,6 @@ import {
 import { getGitHubVersion } from "./api-client";
 import { CommandInvocationError } from "./codeql";
 import * as configUtils from "./config-utils";
-import { Language, parseLanguage } from "./languages";
 import { getActionsLogger } from "./logging";
 import { runResolveBuildEnvironment } from "./resolve-environment";
 import {
@@ -44,16 +43,6 @@ async function run() {
       return;
     }
 
-    const language: Language | undefined = parseLanguage(
-      getRequiredInput("language"),
-    );
-
-    if (language === undefined) {
-      throw new Error(
-        `Did not recognize the language "${getRequiredInput("language")}".`,
-      );
-    }
-
     const gitHubVersion = await getGitHubVersion();
     checkGitHubVersionInRange(gitHubVersion, logger);
 
@@ -69,7 +58,7 @@ async function run() {
       config.codeQLCmd,
       logger,
       workingDirectory,
-      language,
+      getRequiredInput("language"),
     );
     core.setOutput(ENVIRONMENT_OUTPUT_NAME, result);
   } catch (unwrappedError) {

src/resolve-environment.ts

@@ -1,5 +1,9 @@
-import { CODEQL_VERSION_RESOLVE_ENVIRONMENT, getCodeQL } from "./codeql";
-import { Language } from "./languages";
+import {
+  CODEQL_VERSION_LANGUAGE_ALIASING,
+  CODEQL_VERSION_RESOLVE_ENVIRONMENT,
+  getCodeQL,
+} from "./codeql";
+import { parseLanguage } from "./languages";
 import { Logger } from "./logging";
 import * as util from "./util";
 
@@ -7,11 +11,26 @@ export async function runResolveBuildEnvironment(
   cmd: string,
   logger: Logger,
   workingDir: string | undefined,
-  language: Language,
+  languageInput: string,
 ) {
-  logger.startGroup(`Attempting to resolve build environment for ${language}`);
+  logger.startGroup(
+    `Attempting to resolve build environment for ${languageInput}`,
+  );
 
   const codeql = await getCodeQL(cmd);
+
+  let language = languageInput;
+  if (await util.codeQlVersionAbove(codeql, CODEQL_VERSION_LANGUAGE_ALIASING)) {
+    // Delegate to the CodeQL CLI to handle aliasing.
+  } else {
+    // Handle aliasing in the Action using `parseLanguage`.
+    const parsedLanguage = parseLanguage(languageInput)?.toString();
+    if (parsedLanguage === undefined) {
+      throw new Error(`Did not recognize the language '${languageInput}'.`);
+    }
+    language = parsedLanguage;
+  }
+
   let result = {};
 
   // If the CodeQL version in use does not support the `resolve build-environment`