Fix macos ghcup and cabal flags (#4)

* fix short-circuit logic for ghcup based installs of ghc

* fix unrecognized user-config option for cabal v2.0

* update dependencies

src/installer.ts

@@ -85,7 +85,14 @@ async function isInstalled(
       .then(() => p)
       .catch(() => undefined);
 
-    if (installedPath) return success(tool, version, installedPath);
+    if (installedPath) {
+      // Make sure that the correct ghc is used, even if ghcup has set a
+      // default prior to this action being ran.
+      if (tool === 'ghc' && installedPath === ghcupPath)
+        await exec(await ghcupBin(os), ['set', version]);
+
+      return success(tool, version, installedPath);
+    }
   }
 
   if (tool === 'cabal' && os !== 'win32') {
@@ -172,17 +179,23 @@ async function choco(tool: Tool, version: string): Promise<void> {
   ]);
 }
 
-async function ghcup(tool: Tool, version: string, os: OS): Promise<void> {
-  core.info(`Attempting to install ${tool} ${version} using ghcup`);
+async function ghcupBin(os: OS): Promise<string> {
+  const v = '0.1.5';
+  const cachedBin = tc.find('ghcup', v);
+  if (cachedBin) return join(cachedBin, 'ghcup');
 
-  const v = '0.1.4';
   const bin = await tc.downloadTool(
-    `https://downloads.haskell.org/~ghcup/${v}/x86_64-${
+    `https://downloads.haskell.org/ghcup/${v}/x86_64-${
       os === 'darwin' ? 'apple-darwin' : 'linux'
     }-ghcup-${v}`
   );
   await fs.chmod(bin, 0o755);
+  return join(await tc.cacheFile(bin, 'ghcup', 'ghcup', v), 'ghcup');
+}
 
+async function ghcup(tool: Tool, version: string, os: OS): Promise<void> {
+  core.info(`Attempting to install ${tool} ${version} using ghcup`);
+  const bin = await ghcupBin(os);
   await exec(bin, [tool === 'ghc' ? 'install' : 'install-cabal', version]);
   if (tool === 'ghc') await exec(bin, ['set', version]);
 }

src/setup-haskell.ts

@@ -1,9 +1,20 @@
 import * as core from '@actions/core';
+import * as fs from 'fs';
 import {getOpts, getDefaults, Tool} from './opts';
 import {installTool} from './installer';
 import type {OS} from './opts';
 import {exec} from '@actions/exec';
 
+async function cabalConfig(): Promise<string> {
+  let out = Buffer.from('');
+  const append = (b: Buffer): Buffer => (out = Buffer.concat([out, b]));
+  await exec('cabal', ['--help'], {
+    silent: true,
+    listeners: {stdout: append, stderr: append}
+  });
+  return out.toString().trim().split('\n').slice(-1)[0].trim();
+}
+
 (async () => {
   try {
     core.info('Preparing to setup a Haskell environment');
@@ -21,16 +32,19 @@ import {exec} from '@actions/exec';
 
     if (opts.cabal.enable)
       await core.group('Setting up cabal', async () => {
-        await exec(
-          'cabal user-config update -a "http-transport: plain-http" -v3'
-        );
-        await exec('cabal', ['update']);
+        await exec('cabal', ['user-config', 'update'], {silent: true});
+        const configFile = await cabalConfig();
+        fs.appendFileSync(configFile, 'http-transport: plain-http\n');
+
         if (process.platform === 'win32') {
-          await exec('cabal user-config update -a "store-dir: C:\\sr" -v3');
+          fs.appendFileSync(configFile, 'store-dir: C:\\sr\n');
           core.setOutput('cabal-store', 'C:\\sr');
         } else {
           core.setOutput('cabal-store', `${process.env.HOME}/.cabal/store`);
         }
+
+        await exec('cabal user-config update');
+        if (!opts.stack.enable) await exec('cabal update');
       });
   } catch (error) {
     core.setFailed(error.message);