Support custom VIRTUAL_ENV for layout_python (#876)

.github/workflows/go.yml

@@ -25,6 +25,13 @@ jobs:
         go-version: 1.16
       id: go
 
+    - name: Set up Python
+      if: runner.os != 'Windows'
+      uses: actions/setup-python@v4.0.0
+      with:
+        python-version: "3.9"
+      id: python
+
     - name: Check out code into the Go module directory
       uses: actions/checkout@v3.0.2
 

stdlib.sh

@@ -789,9 +789,10 @@ layout_php() {
 
 # Usage: layout python <python_exe>
 #
-# Creates and loads a virtual environment under
+# Creates and loads a virtual environment.
+# You can specify the path of the virtual environment through VIRTUAL_ENV
+# environment variable, otherwise it will be set to
 # "$direnv_layout_dir/python-$python_version".
-# This forces the installation of any egg into the project's sub-folder.
 # For python older then 3.3 this requires virtualenv to be installed.
 #
 # It's possible to specify the python executable if you want to use different
@@ -814,7 +815,13 @@ layout_python() {
       return 1
     fi
 
-    VIRTUAL_ENV=$(direnv_layout_dir)/python-$python_version
+    if [[ -n "${VIRTUAL_ENV:-}" ]]; then
+      local REPLY
+      realpath.absolute "$VIRTUAL_ENV"
+      VIRTUAL_ENV=$REPLY
+    else
+      VIRTUAL_ENV=$(direnv_layout_dir)/python-$python_version
+    fi
     case $ve in
       "venv")
         if [[ ! -d $VIRTUAL_ENV ]]; then
@@ -946,7 +953,9 @@ layout_pipenv() {
 #
 #    layout pyenv 3.6.7
 #
-# Uses pyenv and layout_python to create and load a virtual environment under
+# Uses pyenv and layout_python to create and load a virtual environment.
+# You can specify the path of the virtual environment through VIRTUAL_ENV
+# environment variable, otherwise it will be set to
 # "$direnv_layout_dir/python-$python_version".
 #
 layout_pyenv() {

test/direnv-test-common.sh

@@ -247,6 +247,30 @@ test_start "skip-env"
   test -z "${SKIPPED}"
 test_stop
 
+if has python; then
+  test_start "python-layout"
+    rm -rf .direnv
+
+    direnv_eval
+    test -n "${VIRTUAL_ENV:-}"
+
+    if [[ ":$PATH:" != *":${VIRTUAL_ENV}/bin:"* ]]; then
+      echo "FAILED: VIRTUAL_ENV/bin not added to PATH"
+      exit 1
+    fi
+  test_stop
+
+  test_start "python-custom-virtual-env"
+    direnv_eval
+    test "${VIRTUAL_ENV:-}" -ef ./foo
+
+    if [[ ":$PATH:" != *":${PWD}/foo/bin:"* ]]; then
+      echo "FAILED: VIRTUAL_ENV/bin not added to PATH"
+      exit 1
+    fi
+  test_stop
+fi
+
 test_start "aliases"
   direnv deny
   # check that allow/deny aliases work

test/scenarios/python-custom-virtual-env/.envrc

@@ -0,0 +1,2 @@
+export VIRTUAL_ENV=foo
+layout python

test/scenarios/python-layout/.envrc

@@ -0,0 +1 @@
+layout python