fix cygwin root logic

Author: jmgrosen

dist/index.cjs

@@ -97,6 +97,11 @@ export const OPAM_ROOT = (() => {
   return path.join(os.homedir(), ".opam");
 })();
 
+// opam's internal Cygwin installation paths (only used on Windows)
+export const CYGWIN_ROOT = path.join(OPAM_ROOT, ".cygwin", "root");
+
+export const CYGWIN_ROOT_BIN = path.join(CYGWIN_ROOT, "bin");
+
 export const RUNNER_ENVIRONMENT = ((): "github-hosted" | "self-hosted" => {
   const ImageOS = process.env.ImageOS;
   const RUNNER_ENVIRONMENT = process.env.RUNNER_ENVIRONMENT as

dist/post/index.cjs

@@ -3,9 +3,11 @@ import * as os from "node:os";
 import * as path from "node:path";
 import * as process from "node:process";
 import * as core from "@actions/core";
-import { exec, getExecOutput } from "@actions/exec";
+import { exec } from "@actions/exec";
 import { restoreDuneCache, restoreOpamCaches, saveOpamCache } from "./cache.js";
 import {
+  CYGWIN_ROOT,
+  CYGWIN_ROOT_BIN,
   DUNE_CACHE,
   DUNE_CACHE_ROOT,
   OPAM_PIN,
@@ -26,17 +28,6 @@ import {
 import { retrieveOpamLocalPackages } from "./packages.js";
 import { resolvedCompiler } from "./version.js";
 
-async function getCygwinRoot(): Promise<string> {
-  const { stdout } = await getExecOutput("opam", [
-    "exec",
-    "--",
-    "cygpath",
-    "-w",
-    "/",
-  ]);
-  return stdout.trim();
-}
-
 export async function installer() {
   if (core.isDebug()) {
     core.exportVariable("OPAMVERBOSE", 1);
@@ -71,12 +62,10 @@ export async function installer() {
   const { opamCacheHit } = await restoreOpamCaches();
   await setupOpam();
   if (PLATFORM === "windows") {
-    const cygwinRoot = await getCygwinRoot();
-    const bashEnvPath = path.join(cygwinRoot, "bash_env");
+    const bashEnvPath = path.join(CYGWIN_ROOT, "bash_env");
     await fs.writeFile(bashEnvPath, "set -o igncr");
     core.exportVariable("BASH_ENV", bashEnvPath);
-    const cygwinRootBin = path.join(cygwinRoot, "bin");
-    core.addPath(cygwinRootBin);
+    core.addPath(CYGWIN_ROOT_BIN);
   }
   await repositoryRemoveAll();
   await repositoryAddAll(OPAM_REPOSITORIES);