Final poetry action fix: manually recreate softlinks broken by cachin…

…g. (#10250)

It seems the caching action was not always correctly recreating
softlinks. At first glance, the softlinks it created seemed fine, but
they didn't always work. Possibly hitting some kind of underlying bug,
but not particularly worth debugging in depth -- we can manually create
the soft links we need.

.github/actions/poetry_setup/action.yml

@@ -39,28 +39,43 @@ runs:
       with:
         path: |
           /opt/pipx/venvs/poetry
-          /opt/pipx_bin/poetry
         # This step caches the poetry installation, so make sure it's keyed on the poetry version as well.
         key: bin-poetry-${{ runner.os }}-${{ runner.arch }}-py-${{ inputs.python-version }}-${{ inputs.poetry-version }}
 
-    - name: Install poetry
-      if: steps.cache-bin-poetry.outputs.cache-hit != 'true'
+    - name: Refresh shell hashtable and fixup softlinks
+      if: steps.cache-bin-poetry.outputs.cache-hit == 'true'
       shell: bash
       env:
         POETRY_VERSION: ${{ inputs.poetry-version }}
         PYTHON_VERSION: ${{ inputs.python-version }}
-      run: pipx install "poetry==$POETRY_VERSION" --python "python$PYTHON_VERSION" --verbose
-
-    - name: Refresh shell hashtable and show python/poetry binaries and versions
-      shell: bash
       run: |
         set -eux
+
+        # Refresh the shell hashtable, to ensure correct `which` output.
         hash -r
-        ls -alh /opt/pipx_bin/poetry
-        ls -alh /opt/pipx/venvs/poetry/bin/python
+
+        # `actions/cache@v3` doesn't always seem able to correctly unpack softlinks.
+        # Delete and recreate the softlinks pipx expects to have.
+        rm /opt/pipx/venvs/poetry/bin/python
+        cd /opt/pipx/venvs/poetry/bin
+        ln -s "$(which "python$PYTHON_VERSION")" python
+        chmod +x python
+        cd /opt/pipx_bin/
+        ln -s /opt/pipx/venvs/poetry/bin/poetry poetry
+        chmod +x poetry
+
+        # Ensure everything got set up correctly.
         /opt/pipx/venvs/poetry/bin/python --version
         /opt/pipx_bin/poetry --version
 
+    - name: Install poetry
+      if: steps.cache-bin-poetry.outputs.cache-hit != 'true'
+      shell: bash
+      env:
+        POETRY_VERSION: ${{ inputs.poetry-version }}
+        PYTHON_VERSION: ${{ inputs.python-version }}
+      run: pipx install "poetry==$POETRY_VERSION" --python "python$PYTHON_VERSION" --verbose
+
     - name: Restore pip and poetry cached dependencies
       uses: actions/cache@v3
       env: