Allow sysconfig to override install schemes...

distutils/command/install.py

@@ -4,6 +4,9 @@
 
 import sys
 import os
+import contextlib
+import sysconfig
+import itertools
 
 from distutils import log
 from distutils.core import Command
@@ -20,69 +23,94 @@
 HAS_USER_SITE = True
 
 WINDOWS_SCHEME = {
-    'purelib': '$base/Lib/site-packages',
-    'platlib': '$base/Lib/site-packages',
-    'headers': '$base/Include/$dist_name',
-    'scripts': '$base/Scripts',
-    'data'   : '$base',
+    'purelib': '{base}/Lib/site-packages',
+    'platlib': '{base}/Lib/site-packages',
+    'headers': '{base}/Include/{dist_name}',
+    'scripts': '{base}/Scripts',
+    'data'   : '{base}',
 }
 
 INSTALL_SCHEMES = {
-    'unix_prefix': {
-        'purelib': '$base/lib/$implementation_lower$py_version_short/site-packages',
-        'platlib': '$platbase/$platlibdir/$implementation_lower$py_version_short/site-packages',
-        'headers': '$base/include/$implementation_lower$py_version_short$abiflags/$dist_name',
-        'scripts': '$base/bin',
-        'data'   : '$base',
+    'posix_prefix': {
+        'purelib': '{base}/lib/{implementation_lower}{py_version_short}/site-packages',
+        'platlib': '{platbase}/{platlibdir}/{implementation_lower}{py_version_short}/site-packages',
+        'headers': '{base}/include/{implementation_lower}{py_version_short}{abiflags}/{dist_name}',
+        'scripts': '{base}/bin',
+        'data'   : '{base}',
         },
-    'unix_home': {
-        'purelib': '$base/lib/$implementation_lower',
-        'platlib': '$base/$platlibdir/$implementation_lower',
-        'headers': '$base/include/$implementation_lower/$dist_name',
-        'scripts': '$base/bin',
-        'data'   : '$base',
+    'posix_home': {
+        'purelib': '{base}/lib/{implementation_lower}',
+        'platlib': '{base}/{platlibdir}/{implementation_lower}',
+        'headers': '{base}/include/{implementation_lower}/{dist_name}',
+        'scripts': '{base}/bin',
+        'data'   : '{base}',
         },
     'nt': WINDOWS_SCHEME,
     'pypy': {
-        'purelib': '$base/site-packages',
-        'platlib': '$base/site-packages',
-        'headers': '$base/include/$dist_name',
-        'scripts': '$base/bin',
-        'data'   : '$base',
+        'purelib': '{base}/site-packages',
+        'platlib': '{base}/site-packages',
+        'headers': '{base}/include/{dist_name}',
+        'scripts': '{base}/bin',
+        'data'   : '{base}',
         },
     'pypy_nt': {
-        'purelib': '$base/site-packages',
-        'platlib': '$base/site-packages',
-        'headers': '$base/include/$dist_name',
-        'scripts': '$base/Scripts',
-        'data'   : '$base',
+        'purelib': '{base}/site-packages',
+        'platlib': '{base}/site-packages',
+        'headers': '{base}/include/{dist_name}',
+        'scripts': '{base}/Scripts',
+        'data'   : '{base}',
         },
     }
 
 # user site schemes
 if HAS_USER_SITE:
     INSTALL_SCHEMES['nt_user'] = {
-        'purelib': '$usersite',
-        'platlib': '$usersite',
-        'headers': '$userbase/$implementation$py_version_nodot/Include/$dist_name',
-        'scripts': '$userbase/$implementation$py_version_nodot/Scripts',
-        'data'   : '$userbase',
+        'purelib': '{usersite}',
+        'platlib': '{usersite}',
+        'headers': '{userbase}/{implementation}{py_version_nodot}/Include/{dist_name}',
+        'scripts': '{userbase}/{implementation}{py_version_nodot}/Scripts',
+        'data'   : '{userbase}',
         }
 
-    INSTALL_SCHEMES['unix_user'] = {
-        'purelib': '$usersite',
-        'platlib': '$usersite',
+    INSTALL_SCHEMES['posix_user'] = {
+        'purelib': '{usersite}',
+        'platlib': '{usersite}',
         'headers':
-            '$userbase/include/$implementation_lower$py_version_short$abiflags/$dist_name',
-        'scripts': '$userbase/bin',
-        'data'   : '$userbase',
+            '{userbase}/include/{implementation_lower}{py_version_short}{abiflags}/{dist_name}',
+        'scripts': '{userbase}/bin',
+        'data'   : '{userbase}',
         }
 
 # The keys to an installation scheme; if any new types of files are to be
 # installed, be sure to add an entry to every installation scheme above,
 # and to SCHEME_KEYS here.
 SCHEME_KEYS = ('purelib', 'platlib', 'headers', 'scripts', 'data')
 
+
+def _load_sysconfig_schemes():
+    with contextlib.suppress(AttributeError):
+        return {
+            scheme: sysconfig.get_paths(scheme, expand=False)
+            for scheme in sysconfig.get_scheme_names()
+        }
+
+
+def _load_schemes():
+    """
+    Extend default schemes with schemes from sysconfig.
+    """
+
+    sysconfig_schemes = _load_sysconfig_schemes() or {}
+
+    return {
+        scheme: {
+            **INSTALL_SCHEMES.get(scheme, {}),
+            **sysconfig_schemes.get(scheme, {}),
+        }
+        for scheme in set(itertools.chain(INSTALL_SCHEMES, sysconfig_schemes))
+    }
+
+
 def _get_implementation():
     if hasattr(sys, 'pypy_version_info'):
         return 'PyPy'
@@ -284,7 +312,7 @@ def finalize_options(self):
         # input a heady brew of prefix, exec_prefix, home, install_base,
         # install_platbase, user-supplied versions of
         # install_{purelib,platlib,lib,scripts,data,...}, and the
-        # INSTALL_SCHEME dictionary above.  Phew!
+        # install schemes.  Phew!
 
         self.dump_dirs("pre-finalize_{unix,other}")
 
@@ -335,6 +363,8 @@ def finalize_options(self):
         # everything else.
         self.config_vars['base'] = self.install_base
         self.config_vars['platbase'] = self.install_platbase
+        self.config_vars['installed_base'] = (
+            sysconfig.get_config_vars()['installed_base'])
 
         if DEBUG:
             from pprint import pprint
@@ -431,10 +461,10 @@ def finalize_unix(self):
                 raise DistutilsPlatformError(
                     "User base directory is not specified")
             self.install_base = self.install_platbase = self.install_userbase
-            self.select_scheme("unix_user")
+            self.select_scheme("posix_user")
         elif self.home is not None:
             self.install_base = self.install_platbase = self.home
-            self.select_scheme("unix_home")
+            self.select_scheme("posix_home")
         else:
             if self.prefix is None:
                 if self.exec_prefix is not None:
@@ -450,7 +480,7 @@ def finalize_unix(self):
 
             self.install_base = self.prefix
             self.install_platbase = self.exec_prefix
-            self.select_scheme("unix_prefix")
+            self.select_scheme("posix_prefix")
 
     def finalize_other(self):
         """Finalizes options for non-posix platforms"""
@@ -462,7 +492,7 @@ def finalize_other(self):
             self.select_scheme(os.name + "_user")
         elif self.home is not None:
             self.install_base = self.install_platbase = self.home
-            self.select_scheme("unix_home")
+            self.select_scheme("posix_home")
         else:
             if self.prefix is None:
                 self.prefix = os.path.normpath(sys.prefix)
@@ -484,7 +514,7 @@ def select_scheme(self, name):
                 name = 'pypy_nt'
             else:
                 name = 'pypy'
-        scheme = INSTALL_SCHEMES[name]
+        scheme = _load_schemes()[name]
         for key in SCHEME_KEYS:
             attrname = 'install_' + key
             if getattr(self, attrname) is None:

distutils/tests/test_install.py

@@ -94,7 +94,7 @@ def cleanup():
 
         self.addCleanup(cleanup)
 
-        for key in ('nt_user', 'unix_user'):
+        for key in ('nt_user', 'posix_user'):
             self.assertIn(key, INSTALL_SCHEMES)
 
         dist = Distribution({'name': 'xx'})

distutils/util.py

@@ -242,30 +242,43 @@ def check_environ ():
 
 
 def subst_vars (s, local_vars):
-    """Perform shell/Perl-style variable substitution on 'string'.  Every
-    occurrence of '$' followed by a name is considered a variable, and
-    variable is substituted by the value found in the 'local_vars'
-    dictionary, or in 'os.environ' if it's not in 'local_vars'.
+    """
+    Perform variable substitution on 'string'.
+    Variables are indicated by format-style braces ("{var}").
+    Variable is substituted by the value found in the 'local_vars'
+    dictionary or in 'os.environ' if it's not in 'local_vars'.
     'os.environ' is first checked/augmented to guarantee that it contains
     certain values: see 'check_environ()'.  Raise ValueError for any
     variables not found in either 'local_vars' or 'os.environ'.
     """
     check_environ()
-    def _subst (match, local_vars=local_vars):
-        var_name = match.group(1)
-        if var_name in local_vars:
-            return str(local_vars[var_name])
-        else:
-            return os.environ[var_name]
-
+    lookup = dict(os.environ)
+    lookup.update((name, str(value)) for name, value in local_vars.items())
     try:
-        return re.sub(r'\$([a-zA-Z_][a-zA-Z_0-9]*)', _subst, s)
+        return _subst_compat(s).format_map(lookup)
     except KeyError as var:
-        raise ValueError("invalid variable '$%s'" % var)
+        raise ValueError(f"invalid variable {var}")
 
 # subst_vars ()
 
 
+def _subst_compat(s):
+    """
+    Replace shell/Perl-style variable substitution with
+    format-style. For compatibility.
+    """
+    def _subst(match):
+        return f'{{{match.group(1)}}}'
+    repl = re.sub(r'\$([a-zA-Z_][a-zA-Z_0-9]*)', _subst, s)
+    if repl != s:
+        import warnings
+        warnings.warn(
+            "shell/Perl-style substitions are deprecated",
+            DeprecationWarning,
+        )
+    return repl
+
+
 def grok_environment_error (exc, prefix="error: "):
     # Function kept for backward compatibility.
     # Used to try clever things with EnvironmentErrors,