Add PKG_CONFIG_PATH environment variable support to all activation scripts

docs/changelog/2637.feature.rst

@@ -0,0 +1 @@
+Add ``PKG_CONFIG_PATH`` environment variable support to all activation scripts (Bash, Batch, PowerShell, Fish, C Shell, Nushell, and Python). The virtualenv's ``lib/pkgconfig`` directory is now automatically prepended to ``PKG_CONFIG_PATH`` on activation and restored on deactivation, enabling packages that use ``pkg-config`` during build/install to find their configuration files - by :user:`rahuldevikar`.

src/virtualenv/activation/bash/activate.sh

@@ -33,6 +33,11 @@ deactivate () {
         export TK_LIBRARY
         unset _OLD_VIRTUAL_TK_LIBRARY
     fi
+    if ! [ -z "${_OLD_PKG_CONFIG_PATH+_}" ]; then
+        PKG_CONFIG_PATH="$_OLD_PKG_CONFIG_PATH"
+        export PKG_CONFIG_PATH
+        unset _OLD_PKG_CONFIG_PATH
+    fi
 
     # The hash command must be called to get it to forget past
     # commands. Without forgetting past commands the $PATH changes
@@ -74,6 +79,10 @@ _OLD_VIRTUAL_PATH="$PATH"
 PATH="$VIRTUAL_ENV/"__BIN_NAME__":$PATH"
 export PATH
 
+_OLD_PKG_CONFIG_PATH="${PKG_CONFIG_PATH}"
+PKG_CONFIG_PATH="${VIRTUAL_ENV}/lib/pkgconfig:${PKG_CONFIG_PATH}"
+export PKG_CONFIG_PATH
+
 if [ "x"__VIRTUAL_PROMPT__ != x ] ; then
     VIRTUAL_ENV_PROMPT=__VIRTUAL_PROMPT__
 else

src/virtualenv/activation/batch/activate.bat

@@ -39,6 +39,9 @@
 @if defined TK_LIBRARY @set "_OLD_VIRTUAL_TK_LIBRARY=%TK_LIBRARY%"
 @if NOT "__TK_LIBRARY__"=="" @set "TK_LIBRARY=__TK_LIBRARY__"
 
+@if defined PKG_CONFIG_PATH @set "_OLD_PKG_CONFIG_PATH=%PKG_CONFIG_PATH%"
+@set "PKG_CONFIG_PATH=%VIRTUAL_ENV%\lib\pkgconfig;%PKG_CONFIG_PATH%"
+
 @REM if defined _OLD_VIRTUAL_PATH (
 @if not defined _OLD_VIRTUAL_PATH @goto ENDIFVPATH1
     @set "PATH=%_OLD_VIRTUAL_PATH%"

src/virtualenv/activation/batch/deactivate.bat

@@ -20,6 +20,10 @@
 @if not defined _OLD_VIRTUAL_TK_LIBRARY @set TK_LIBRARY=
 @set _OLD_VIRTUAL_TK_LIBRARY=
 
+@if defined _OLD_PKG_CONFIG_PATH @set "PKG_CONFIG_PATH=%_OLD_PKG_CONFIG_PATH%"
+@if not defined _OLD_PKG_CONFIG_PATH @set PKG_CONFIG_PATH=
+@set _OLD_PKG_CONFIG_PATH=
+
 @if not defined _OLD_VIRTUAL_PATH @goto ENDIFVPATH
     @set "PATH=%_OLD_VIRTUAL_PATH%"
     @set _OLD_VIRTUAL_PATH=

src/virtualenv/activation/cshell/activate.csh

@@ -5,7 +5,7 @@
 set newline='\
 '
 
-alias deactivate 'test $?_OLD_VIRTUAL_PATH != 0 && setenv PATH "$_OLD_VIRTUAL_PATH:q" && unset _OLD_VIRTUAL_PATH; rehash; test $?_OLD_VIRTUAL_TCL_LIBRARY != 0 && setenv TCL_LIBRARY "$_OLD_VIRTUAL_TCL_LIBRARY:q" && unset _OLD_VIRTUAL_TCL_LIBRARY || unsetenv TCL_LIBRARY; test $?_OLD_VIRTUAL_TK_LIBRARY != 0 && setenv TK_LIBRARY "$_OLD_VIRTUAL_TK_LIBRARY:q" && unset _OLD_VIRTUAL_TK_LIBRARY || unsetenv TK_LIBRARY; test $?_OLD_VIRTUAL_PROMPT != 0 && set prompt="$_OLD_VIRTUAL_PROMPT:q" && unset _OLD_VIRTUAL_PROMPT; unsetenv VIRTUAL_ENV; unsetenv VIRTUAL_ENV_PROMPT; test "\!:*" != "nondestructive" && unalias deactivate && unalias pydoc'
+alias deactivate 'test $?_OLD_VIRTUAL_PATH != 0 && setenv PATH "$_OLD_VIRTUAL_PATH:q" && unset _OLD_VIRTUAL_PATH; rehash; test $?_OLD_VIRTUAL_TCL_LIBRARY != 0 && setenv TCL_LIBRARY "$_OLD_VIRTUAL_TCL_LIBRARY:q" && unset _OLD_VIRTUAL_TCL_LIBRARY || unsetenv TCL_LIBRARY; test $?_OLD_VIRTUAL_TK_LIBRARY != 0 && setenv TK_LIBRARY "$_OLD_VIRTUAL_TK_LIBRARY:q" && unset _OLD_VIRTUAL_TK_LIBRARY || unsetenv TK_LIBRARY; test $?_OLD_PKG_CONFIG_PATH != 0 && setenv PKG_CONFIG_PATH "$_OLD_PKG_CONFIG_PATH:q" && unset _OLD_PKG_CONFIG_PATH || unsetenv PKG_CONFIG_PATH; test $?_OLD_VIRTUAL_PROMPT != 0 && set prompt="$_OLD_VIRTUAL_PROMPT:q" && unset _OLD_VIRTUAL_PROMPT; unsetenv VIRTUAL_ENV; unsetenv VIRTUAL_ENV_PROMPT; test "\!:*" != "nondestructive" && unalias deactivate && unalias pydoc'
 
 # Unset irrelevant variables.
 deactivate nondestructive
@@ -15,6 +15,13 @@ setenv VIRTUAL_ENV __VIRTUAL_ENV__
 set _OLD_VIRTUAL_PATH="$PATH:q"
 setenv PATH "$VIRTUAL_ENV:q/"__BIN_NAME__":$PATH:q"
 
+if ($?PKG_CONFIG_PATH) then
+    set _OLD_PKG_CONFIG_PATH="$PKG_CONFIG_PATH"
+    setenv PKG_CONFIG_PATH "${VIRTUAL_ENV}/lib/pkgconfig:${PKG_CONFIG_PATH}"
+else
+    setenv PKG_CONFIG_PATH "${VIRTUAL_ENV}/lib/pkgconfig"
+endif
+
 if (__TCL_LIBRARY__ != "") then
     if ($?TCL_LIBRARY) then
         set _OLD_VIRTUAL_TCL_LIBRARY="$TCL_LIBRARY"

src/virtualenv/activation/fish/activate.fish

@@ -43,6 +43,11 @@ function deactivate -d 'Exit virtualenv mode and return to the normal environmen
       end
     end
 
+    if test -n "$_OLD_PKG_CONFIG_PATH"
+        set -gx PKG_CONFIG_PATH "$_OLD_PKG_CONFIG_PATH"
+        set -e _OLD_PKG_CONFIG_PATH
+    end
+
     if test -n "$_OLD_VIRTUAL_PYTHONHOME"
         set -gx PYTHONHOME "$_OLD_VIRTUAL_PYTHONHOME"
         set -e _OLD_VIRTUAL_PYTHONHOME
@@ -77,6 +82,9 @@ deactivate nondestructive
 
 set -gx VIRTUAL_ENV __VIRTUAL_ENV__
 
+set -gx _OLD_PKG_CONFIG_PATH "$PKG_CONFIG_PATH"
+set -gx PKG_CONFIG_PATH "$VIRTUAL_ENV/lib/pkgconfig:$PKG_CONFIG_PATH"
+
 # https://github.com/fish-shell/fish-shell/issues/436 altered PATH handling
 if test (string sub -s 1 -l 1 $FISH_VERSION) -lt 3
     set -gx _OLD_VIRTUAL_PATH (_bashify_path $PATH)

src/virtualenv/activation/nushell/activate.nu

@@ -57,7 +57,9 @@ export-env {
     } else {
         __VIRTUAL_PROMPT__
     }
-    let new_env = { $path_name: $new_path VIRTUAL_ENV: $virtual_env VIRTUAL_ENV_PROMPT: $virtual_env_prompt }
+    let old_pkg_config_path = if (has-env 'PKG_CONFIG_PATH') { $env.PKG_CONFIG_PATH } else { '' }
+    let new_pkg_config_path = $'($virtual_env)/lib/pkgconfig:($old_pkg_config_path)'
+    let new_env = { $path_name: $new_path VIRTUAL_ENV: $virtual_env VIRTUAL_ENV_PROMPT: $virtual_env_prompt PKG_CONFIG_PATH: $new_pkg_config_path }
     if (has-env 'TCL_LIBRARY')  {
         let $new_env = $new_env | insert TCL_LIBRARY __TCL_LIBRARY__
     }

src/virtualenv/activation/powershell/activate.ps1

@@ -25,6 +25,11 @@ function global:deactivate([switch] $NonDestructive) {
         }
     }
 
+    if (Test-Path variable:_OLD_PKG_CONFIG_PATH) {
+        $env:PKG_CONFIG_PATH = $variable:_OLD_PKG_CONFIG_PATH
+        Remove-Variable "_OLD_PKG_CONFIG_PATH" -Scope global
+    }
+
     if (Test-Path function:_old_virtual_prompt) {
         $function:prompt = $function:_old_virtual_prompt
         Remove-Item function:\_old_virtual_prompt
@@ -78,6 +83,11 @@ if (__TK_LIBRARY__ -ne "") {
 
 New-Variable -Scope global -Name _OLD_VIRTUAL_PATH -Value $env:PATH
 
+if (Test-Path env:PKG_CONFIG_PATH) {
+    New-Variable -Scope global -Name _OLD_PKG_CONFIG_PATH -Value $env:PKG_CONFIG_PATH
+}
+$env:PKG_CONFIG_PATH = "$env:VIRTUAL_ENV\lib\pkgconfig;$env:PKG_CONFIG_PATH"
+
 $env:PATH = "$env:VIRTUAL_ENV/" + __BIN_NAME__ + __PATH_SEP__ + $env:PATH
 if (!$env:VIRTUAL_ENV_DISABLE_PROMPT) {
     function global:_old_virtual_prompt {

src/virtualenv/activation/python/activate_this.py

@@ -27,6 +27,14 @@
 os.environ["VIRTUAL_ENV"] = base  # virtual env is right above bin directory
 os.environ["VIRTUAL_ENV_PROMPT"] = __VIRTUAL_PROMPT__ or os.path.basename(base)
 
+# Set PKG_CONFIG_PATH to include the virtualenv's pkgconfig directory
+pkg_config_path = os.path.join(base, "lib", "pkgconfig")
+existing_pkg_config_path = os.environ.get("PKG_CONFIG_PATH", "")
+if existing_pkg_config_path:
+    os.environ["PKG_CONFIG_PATH"] = os.pathsep.join([pkg_config_path, existing_pkg_config_path])
+else:
+    os.environ["PKG_CONFIG_PATH"] = pkg_config_path
+
 # add the virtual environments libraries to the host python import mechanism
 prev_length = len(sys.path)
 for lib in __LIB_FOLDERS__.split(os.pathsep):

tests/unit/activation/test_pkg_config_path.py

@@ -0,0 +1,177 @@
+"""Test that PKG_CONFIG_PATH is properly set and restored during activation/deactivation."""
+
+from __future__ import annotations
+
+from argparse import Namespace
+
+import pytest
+
+from virtualenv.activation import (
+    BashActivator,
+    BatchActivator,
+    CShellActivator,
+    FishActivator,
+    NushellActivator,
+    PowerShellActivator,
+    PythonActivator,
+)
+from virtualenv.info import IS_WIN
+
+
+def _create_test_env(tmp_path):
+    """Helper to create a mock virtualenv environment for testing."""
+
+    class MockInterpreter:
+        tcl_lib = None
+        tk_lib = None
+
+    class MockCreator:
+        def __init__(self, dest):
+            self.dest = dest
+            self.bin_dir = dest / ("Scripts" if IS_WIN else "bin")
+            self.bin_dir.mkdir(parents=True)
+            self.interpreter = MockInterpreter()
+            self.pyenv_cfg = {}
+            self.env_name = "test-env"
+
+    return MockCreator(tmp_path)
+
+
+@pytest.mark.parametrize(
+    ("activator_class", "script_name", "search_patterns"),
+    [
+        (
+            BashActivator,
+            "activate",
+            {
+                "save": '_OLD_PKG_CONFIG_PATH="${PKG_CONFIG_PATH}"',
+                "set": 'PKG_CONFIG_PATH="${VIRTUAL_ENV}/lib/pkgconfig:${PKG_CONFIG_PATH}"',
+                "export": "export PKG_CONFIG_PATH",
+                "restore": 'PKG_CONFIG_PATH="$_OLD_PKG_CONFIG_PATH"',
+                "unset": "unset _OLD_PKG_CONFIG_PATH",
+            },
+        ),
+        (
+            FishActivator,
+            "activate.fish",
+            {
+                "save": "set -gx _OLD_PKG_CONFIG_PATH",
+                "set": 'set -gx PKG_CONFIG_PATH "$VIRTUAL_ENV/lib/pkgconfig:$PKG_CONFIG_PATH"',
+                "restore": "set -gx PKG_CONFIG_PATH",
+                "erase": "set -e _OLD_PKG_CONFIG_PATH",
+            },
+        ),
+        (
+            CShellActivator,
+            "activate.csh",
+            {
+                "save": 'set _OLD_PKG_CONFIG_PATH="$PKG_CONFIG_PATH"',
+                "set_with_existing": 'setenv PKG_CONFIG_PATH "${VIRTUAL_ENV}/lib/pkgconfig:${PKG_CONFIG_PATH}"',
+                "set_without_existing": 'setenv PKG_CONFIG_PATH "${VIRTUAL_ENV}/lib/pkgconfig"',
+                "deactivate_test": "test $?_OLD_PKG_CONFIG_PATH != 0",
+                "restore": 'setenv PKG_CONFIG_PATH "$_OLD_PKG_CONFIG_PATH:q"',
+                "unset": "unset _OLD_PKG_CONFIG_PATH",
+            },
+        ),
+    ],
+)
+def test_pkg_config_path_unix_shells(tmp_path, activator_class, script_name, search_patterns):
+    """Test PKG_CONFIG_PATH is set for Unix-like shells."""
+    if IS_WIN and activator_class in {BashActivator, FishActivator, CShellActivator}:
+        pytest.skip("Unix shell test on Windows")
+
+    creator = _create_test_env(tmp_path)
+    options = Namespace(prompt=None)
+    activator = activator_class(options)
+
+    # Generate the activation script
+    activator.generate(creator)
+
+    # Read the generated script
+    script_path = creator.bin_dir / script_name
+    content = script_path.read_text(encoding="utf-8")
+
+    # Verify all expected patterns are present
+    for pattern_name, pattern in search_patterns.items():
+        assert pattern in content, f"Missing {pattern_name} pattern: {pattern}\nScript content:\n{content}"
+
+
+@pytest.mark.skipif(not IS_WIN, reason="Windows-only test")
+@pytest.mark.parametrize(
+    ("activator_class", "script_name", "search_patterns"),
+    [
+        (
+            BatchActivator,
+            "activate.bat",
+            {
+                "save": 'set "_OLD_PKG_CONFIG_PATH=%PKG_CONFIG_PATH%"',
+                "set": 'set "PKG_CONFIG_PATH=%VIRTUAL_ENV%\\lib\\pkgconfig;%PKG_CONFIG_PATH%"',
+            },
+        ),
+        (
+            PowerShellActivator,
+            "activate.ps1",
+            {
+                "save": "New-Variable -Scope global -Name _OLD_PKG_CONFIG_PATH",
+                "set": '$env:PKG_CONFIG_PATH = "$env:VIRTUAL_ENV\\lib\\pkgconfig;$env:PKG_CONFIG_PATH"',
+                "restore": "$env:PKG_CONFIG_PATH = $variable:_OLD_PKG_CONFIG_PATH",
+                "remove": 'Remove-Variable "_OLD_PKG_CONFIG_PATH" -Scope global',
+            },
+        ),
+    ],
+)
+def test_pkg_config_path_windows_shells(tmp_path, activator_class, script_name, search_patterns):
+    """Test PKG_CONFIG_PATH is set for Windows shells."""
+    creator = _create_test_env(tmp_path)
+    options = Namespace(prompt=None)
+    activator = activator_class(options)
+
+    # Generate the activation script
+    activator.generate(creator)
+
+    # Read the generated script
+    script_path = creator.bin_dir / script_name
+    content = script_path.read_text(encoding="utf-8")
+
+    # Verify all expected patterns are present
+    for pattern_name, pattern in search_patterns.items():
+        assert pattern in content, f"Missing {pattern_name} pattern: {pattern}\nScript content:\n{content}"
+
+
+def test_pkg_config_path_python_activator(tmp_path):
+    """Test PKG_CONFIG_PATH is set in Python activator."""
+    creator = _create_test_env(tmp_path)
+    # Add libs attribute needed by PythonActivator
+    creator.libs = [tmp_path / "Lib" / "site-packages"]
+    options = Namespace(prompt=None)
+    activator = PythonActivator(options)
+
+    # Generate the activation script
+    activator.generate(creator)
+
+    # Read the generated script
+    script_path = creator.bin_dir / "activate_this.py"
+    content = script_path.read_text(encoding="utf-8")
+
+    # Verify PKG_CONFIG_PATH is handled
+    assert "PKG_CONFIG_PATH" in content, f"PKG_CONFIG_PATH not found in activate_this.py:\n{content}"
+    assert "pkg_config_path" in content, f"pkg_config_path variable not found in activate_this.py:\n{content}"
+
+
+def test_pkg_config_path_nushell(tmp_path):
+    """Test PKG_CONFIG_PATH is set in Nushell."""
+    creator = _create_test_env(tmp_path)
+    options = Namespace(prompt=None)
+    activator = NushellActivator(options)
+
+    # Generate the activation script
+    activator.generate(creator)
+
+    # Read the generated script
+    script_path = creator.bin_dir / "activate.nu"
+    content = script_path.read_text(encoding="utf-8")
+
+    # Verify PKG_CONFIG_PATH is handled
+    assert "PKG_CONFIG_PATH" in content, f"PKG_CONFIG_PATH not found in activate.nu:\n{content}"
+    assert "old_pkg_config_path" in content, f"old_pkg_config_path variable not saved in activate.nu:\n{content}"
+    assert "new_pkg_config_path" in content, f"new_pkg_config_path variable not found in activate.nu:\n{content}"