Change Nushell activation script to module (#2422)

docs/changelog/2422.feature.rst

@@ -0,0 +1 @@
+Change Nushell activation script to be a module meant to be activated as an overlay.

src/virtualenv/activation/nushell/__init__.py

@@ -1,4 +1,3 @@
-import os
 from pathlib import Path
 
 from ..via_template import ViaTemplateActivator
@@ -7,20 +6,13 @@
 class NushellActivator(ViaTemplateActivator):
     def templates(self):
         yield Path("activate.nu")
-        yield Path("deactivate.nu")
-
-    def replacements(self, creator, dest_folder):
-        # Due to nushell scoping, it isn't easy to create a function that will
-        # deactivate the environment. For that reason a __DEACTIVATE_PATH__
-        # replacement pointing to the deactivate.nu file is created
 
+    def replacements(self, creator, dest_folder):  # noqa: U100
         return {
             "__VIRTUAL_PROMPT__": "" if self.flag_prompt is None else self.flag_prompt,
             "__VIRTUAL_ENV__": str(creator.dest),
             "__VIRTUAL_NAME__": creator.env_name,
             "__BIN_NAME__": str(creator.bin_dir.relative_to(creator.dest)),
-            "__PATH_SEP__": os.pathsep,
-            "__DEACTIVATE_PATH__": str(Path(dest_folder) / "deactivate.nu"),
         }
 
 

src/virtualenv/activation/nushell/activate.nu

@@ -1,5 +1,12 @@
-# This command prepares the required environment variables
-def-env activate-virtualenv [] {
+# virtualenv activation module
+# Activate with `overlay use activate.nu`
+# Deactivate with `deactivate`, as usual
+#
+# To customize the overlay name, you can call `overlay use activate.nu as foo`,
+# but then simply `deactivate` won't work because it is just an alias to hide
+# the "activate" overlay. You'd need to call `overlay hide foo` manually.
+
+export-env {
     def is-string [x] {
         ($x | describe) == 'string'
     }
@@ -8,10 +15,10 @@ def-env activate-virtualenv [] {
         $name in (env).name
     }
 
-    let is_windows = ((sys).host.name | str downcase) == 'windows'
+    let is_windows = ($nu.os-info.name | str downcase) == 'windows'
     let virtual_env = '__VIRTUAL_ENV__'
     let bin = '__BIN_NAME__'
-    let path_sep = '__PATH_SEP__'
+    let path_sep = (char esep)
     let path_name = if $is_windows {
         if (has-env 'Path') {
             'Path'
@@ -50,7 +57,7 @@ def-env activate-virtualenv [] {
     }
 
     # Back up the old prompt builder
-    let old_prompt_command = if (has-env 'VIRTUAL_ENV') && (has-env '_OLD_PROMPT_COMMAND') {
+    let old_prompt_command = if (has-env 'VIRTUAL_ENV') and (has-env '_OLD_PROMPT_COMMAND') {
         $env._OLD_PROMPT_COMMAND
     } else {
         if (has-env 'PROMPT_COMMAND') {
@@ -71,22 +78,16 @@ def-env activate-virtualenv [] {
         { $'($virtual_prompt)' }
     }
 
-    # Environment variables that will be batched loaded to the virtual env
-    let new_env = {
+    # Environment variables that will be loaded as the virtual env
+    load-env {
         $path_name          : $new_path
         VIRTUAL_ENV         : $virtual_env
         _OLD_VIRTUAL_PATH   : ($old_path | str collect $path_sep)
         _OLD_PROMPT_COMMAND : $old_prompt_command
         PROMPT_COMMAND      : $new_prompt
         VIRTUAL_PROMPT      : $virtual_prompt
     }
-
-    # Activate the environment variables
-    load-env $new_env
 }
 
-# Activate the virtualenv
-activate-virtualenv
-
-alias pydoc = python -m pydoc
-alias deactivate = source '__DEACTIVATE_PATH__'
+export alias pydoc = python -m pydoc
+export alias deactivate = overlay hide activate

tests/unit/activation/test_nushell.py

@@ -13,9 +13,16 @@ def __init__(self, session):
 
             super().__init__(NushellActivator, session, cmd, "activate.nu", "nu")
 
+            self.activate_cmd = "overlay use"
             self.unix_line_ending = not IS_WIN
 
         def print_prompt(self):
             return r"$env.VIRTUAL_PROMPT"
 
+        def activate_call(self, script):
+            # Commands are called without quotes in Nushell
+            cmd = self.activate_cmd
+            scr = self.quote(str(script))
+            return f"{cmd} {scr}".strip()
+
     activation_tester(Nushell)