feat(python): add auto venv activation (#12248)

Co-authored-by: Carlo Sala <carlosalag@protonmail.com>

plugins/python/python.plugin.zsh

@@ -51,11 +51,12 @@ alias pyserver="python3 -m http.server"
 
 
 ## venv utilities
+: ${PYTHON_VENV_NAME:=venv}
 
 # Activate a the python virtual environment specified.
-# If none specified, use 'venv'.
+# If none specified, use $PYTHON_VENV_NAME, else 'venv'.
 function vrun() {
-  local name="${1:-venv}"
+  local name="${1:-$PYTHON_VENV_NAME}"
   local venvpath="${name:P}"
 
   if [[ ! -d "$venvpath" ]]; then
@@ -72,12 +73,26 @@ function vrun() {
   echo "Activated virtual environment ${name}"
 }
 
-# Create a new virtual environment, with default name 'venv'.
+# Create a new virtual environment using the specified name.
+# If none specfied, use $PYTHON_VENV_NAME
 function mkv() {
-  local name="${1:-venv}"
+  local name="${1:-$PYTHON_VENV_NAME}"
   local venvpath="${name:P}"
 
   python3 -m venv "${name}" || return
   echo >&2 "Created venv in '${venvpath}'"
   vrun "${name}"
 }
+
+if [[ "$PYTHON_AUTO_VRUN" == "true" ]]; then
+  # Automatically activate venv when changing dir
+  auto_vrun() {
+    if [[ -f "${PYTHON_VENV_NAME}/bin/activate" ]]; then
+      source "${PYTHON_VENV_NAME}/bin/activate" > /dev/null 2>&1
+    else
+      (( $+functions[deactivate] )) && deactivate > /dev/null 2>&1
+    fi
+  }
+  add-zsh-hook chpwd auto_vrun
+  auto_vrun
+fi