Fix zsh parse error in pipenv shell command (#6504)

Fixes #6503

The previous implementation used 'declare -f' inside an eval statement for
both bash and zsh. However, zsh handles command substitution differently -
it expands $() before parsing the function definition, causing a parse
error: 'zsh: parse error near }''

This fix separates the zsh and bash cases:
- zsh: Uses 'functions -c' to copy function definitions (same approach as fish)
- bash: Continues using 'declare -f' which works correctly in bash

Also enhanced the test to verify zsh uses 'functions -c' (not 'declare -f')
to prevent future regressions.

Author: matteius

pipenv/shells.py

@@ -105,8 +105,14 @@ def _get_deactivate_wrapper_script(cmd):
             "function deactivate { & $_pipenv_old_deactivate; "
             "Remove-Item Env:PIPENV_ACTIVE -ErrorAction SilentlyContinue }"
         )
-    elif cmd.endswith(("bash", "zsh")):
-        # Bash and zsh support 'declare -f' to copy function definitions
+    elif cmd.endswith("zsh"):
+        # Zsh uses 'functions -c' to copy function definitions
+        return (
+            "functions -c deactivate _pipenv_old_deactivate; "
+            "deactivate() { _pipenv_old_deactivate; unset PIPENV_ACTIVE; }"
+        )
+    elif cmd.endswith("bash"):
+        # Bash uses 'declare -f' to copy function definitions
         return (
             'eval "_pipenv_old_deactivate() { $(declare -f deactivate | tail -n +2) }"; '
             "deactivate() { _pipenv_old_deactivate; unset PIPENV_ACTIVE; }"

tests/unit/test_core.py

@@ -176,14 +176,19 @@ def test_load_dot_env_suppresses_message_when_pipenv_active(monkeypatch, capsys,
 @pytest.mark.core
 def test_deactivate_wrapper_script_includes_unset_pipenv_active():
     """Test that deactivate wrapper scripts include 'unset PIPENV_ACTIVE' or equivalent."""
-    # Test bash/zsh - should use 'unset PIPENV_ACTIVE'
+    # Test bash - should use 'declare -f' to copy function and 'unset PIPENV_ACTIVE'
     bash_script = _get_deactivate_wrapper_script("bash")
     assert "unset PIPENV_ACTIVE" in bash_script
     assert "_pipenv_old_deactivate" in bash_script
+    assert "declare -f" in bash_script
 
+    # Test zsh - should use 'functions -c' to copy function (not 'declare -f' which fails in zsh)
+    # See: https://github.com/pypa/pipenv/issues/6503
     zsh_script = _get_deactivate_wrapper_script("zsh")
     assert "unset PIPENV_ACTIVE" in zsh_script
     assert "_pipenv_old_deactivate" in zsh_script
+    assert "functions -c" in zsh_script
+    assert "declare -f" not in zsh_script  # zsh doesn't handle this in eval correctly
 
     # Test fish - should use 'set -e PIPENV_ACTIVE'
     fish_script = _get_deactivate_wrapper_script("fish")