From 511ac68353faed9a70fe74281ca050ea6b67d657 Mon Sep 17 00:00:00 2001
From: "Michael B. Gale" <mbg@github.com>
Date: Fri, 9 Oct 2026 11:35:54 +0100
Subject: [PATCH] Use `macOSVersion` in `isSwiftCompatible`

---
 lib/entry-points.js         | 22 +++++++++++++++++++++-
 src/languages/swift.test.ts | 18 +++++++++++++++++-
 src/languages/swift.ts      | 24 +++++++++++++++++++-----
 3 files changed, 57 insertions(+), 7 deletions(-)

diff --git a/lib/entry-points.js b/lib/entry-points.js
index eccce77eb..e727825c6 100644
--- a/lib/entry-points.js
+++ b/lib/entry-points.js
@@ -175650,6 +175650,16 @@ function getBundlePlatform(platform2 = process.platform, arch2 = process.arch) {
       return void 0;
   }
 }
+function macOSVersion(action) {
+  if (action.platform !== "darwin") {
+    return void 0;
+  }
+  const version = semver7.parse(action.osRelease);
+  if (version === null) {
+    return action.osRelease;
+  }
+  return version;
+}
 
 // src/per-language-bundles.ts
 var MIN_PER_LANGUAGE_BUNDLE_CLI_VERSION = "2.27.1";
@@ -186035,11 +186045,21 @@ async function getToolsInput(action, repositoryProperties) {
 
 // src/languages/swift.ts
 function isSwiftCompatible(action, config) {
-  if (config.languages.includes("swift" /* swift */) && action.platform !== "darwin") {
+  if (!config.languages.includes("swift" /* swift */)) {
+    return;
+  }
+  const version = macOSVersion(action);
+  if (version === void 0) {
     throw new ConfigurationError(
       `Swift analysis is only supported on macOS runner images. Please migrate to a macOS runner.`
     );
   }
+  if (typeof version === "string") {
+    action.logger.warning(
+      `Unable to determine version of macOS, got: ${version}`
+    );
+    return;
+  }
 }
 
 // src/status-report/tools-download.ts
diff --git a/src/languages/swift.test.ts b/src/languages/swift.test.ts
index b0ddc89a3..ecbaae76f 100644
--- a/src/languages/swift.test.ts
+++ b/src/languages/swift.test.ts
@@ -1,6 +1,11 @@
 import test from "ava";
 
-import { createTestConfig, initAllState } from "../testing-utils";
+import {
+  checkExpectedLogMessages,
+  createTestConfig,
+  initAllState,
+  RecordingLogger,
+} from "../testing-utils";
 
 import { isSwiftCompatible } from "./swift";
 
@@ -41,3 +46,14 @@ for (const nonDarwinPlatform of nonDarwinPlatforms) {
     });
   });
 }
+
+test("isSwiftCompatible warns if version string is not a semver", (t) => {
+  const logger = new RecordingLogger();
+  isSwiftCompatible(
+    initAllState({ logger, platform: "darwin", osRelease: "unexpected" }),
+    createTestConfig({ languages: [BuiltInLanguage.swift] }),
+  );
+  checkExpectedLogMessages(t, logger.messages, [
+    "Unable to determine version of macOS, got: unexpected",
+  ]);
+});
diff --git a/src/languages/swift.ts b/src/languages/swift.ts
index 501e7a027..fa6517c6d 100644
--- a/src/languages/swift.ts
+++ b/src/languages/swift.ts
@@ -1,5 +1,6 @@
 import { ActionState } from "../action-common";
 import { Config } from "../config-utils";
+import { macOSVersion } from "../platform";
 import { ConfigurationError } from "../util";
 
 import { BuiltInLanguage } from ".";
@@ -14,15 +15,28 @@ import { BuiltInLanguage } from ".";
  * @returns True if we can run a Swift analysis.
  */
 export function isSwiftCompatible(
-  action: ActionState<["Base"]>,
+  action: ActionState<["Base", "Logger"]>,
   config: Config,
 ) {
-  if (
-    config.languages.includes(BuiltInLanguage.swift) &&
-    action.platform !== "darwin"
-  ) {
+  // The checks are not relevant if we are not trying to analyse Swift.
+  if (!config.languages.includes(BuiltInLanguage.swift)) {
+    return;
+  }
+
+  // Try to get the macOS version.
+  const version = macOSVersion(action);
+
+  // If `version` is undefined, then we are not on macOS.
+  if (version === undefined) {
     throw new ConfigurationError(
       `Swift analysis is only supported on macOS runner images. Please migrate to a macOS runner.`,
     );
   }
+  // If we got a string, we are on macOS but couldn't parse the version string.
+  if (typeof version === "string") {
+    action.logger.warning(
+      `Unable to determine version of macOS, got: ${version}`,
+    );
+    return;
+  }
 }