Fix #130: ensure cabal installdir is in the PATH (#165)

Add  `~/.cabal/bin` to the PATH under Linux and macOS.  
Windows' chocolatey install already takes care of this.

That the `installdir` is in the `PATH` is now tested in CI via a `cabal install` with subsequent call to the installed executable.

Original commits:
* CI issue #130: test whether installdir is in the PATH
* Linux/macOS: add ~/.cabal/bin to PATH
* Inform that installdir is added to PATH

.github/workflows/workflow.yml

@@ -78,6 +78,11 @@ jobs:
  cabal-version: ${{ matrix.cabal }}
  cabal-update: ${{ matrix.cabal_update }}
 
+ - name: Show installed versions
+ run: |
+ cabal --version
+ ghc --version
+
  - name: Test runghc
  run: |
  runghc --version
@@ -91,16 +96,19 @@ jobs:
  working-directory: setup/__tests__/project
  run: cabal run
 
+ - name: Install test project
+ working-directory: setup/__tests__/project
+ run: cabal install
+
+ - name: Run installed test project
+ run: hello-haskell-setup
+ # This tests whether the default installdir has been added to the PATH (issue #130).
+
  - name: Build and run test with Hackage dependency
  if: ${{ matrix.cabal_update != 'false' }}
  working-directory: setup/__tests__/project-with-hackage-dependency
  run: cabal build && cabal run
 
- - name: Show installed versions
- run: |
- cabal --version
- ghc --version
-
  - name: Confirm installed and expected versions match
  shell: bash
  # check that if given in the matrix, the actual version matches:

setup/__tests__/project/project.cabal

@@ -3,7 +3,7 @@ name: project
 version: 0.1.0.0
 build-type: Simple
 
-executable project
+executable hello-haskell-setup
  main-is: Main.hs
  build-depends: base
  default-language: Haskell2010

setup/src/setup-haskell.ts

@@ -57,6 +57,10 @@ export default async function run(
  core.setOutput('cabal-store', 'C:\\sr');
  } else {
  core.setOutput('cabal-store', `${process.env.HOME}/.cabal/store`);
+ // Issue #130: for non-choco installs, add ~/.cabal/bin to PATH
+ const installdir = `${process.env.HOME}/.cabal/bin`;
+ core.info(`Adding ${installdir} to PATH`);
+ core.addPath(installdir);
  }
 
  // Workaround the GHC nopie linking errors for ancient GHC versions