From f1eb1d26a45dd02bb1bb06b2d979596a5ef5a92f Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sat, 23 Jan 2021 16:11:37 -0500
Subject: [PATCH 01/16] Allow sysconfig to override install schemes and provide
 some compatibility overrides for debian and fedora until they patch
 sysconfig.

---
 distutils/command/install.py | 50 ++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 13feeb89..f3dce84b 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -35,6 +35,13 @@
         'scripts': '$base/bin',
         'data'   : '$base',
         },
+    'unix_local': {
+        'purelib': '$base/local/lib/python$py_version_short/site-packages',
+        'platlib': '$platbase/local/$platlibdir/python$py_version_short/site-packages',
+        'headers': '$base/local/include/python$py_version_short$abiflags/$dist_name',
+        'scripts': '$base/local/bin',
+        'data'   : '$base/local',
+        },
     'unix_home': {
         'purelib': '$base/lib/python',
         'platlib': '$base/$platlibdir/python',
@@ -282,6 +289,7 @@ def finalize_options(self):
 
         self.dump_dirs("pre-finalize_{unix,other}")
 
+        self._load_schemes()
         if os.name == 'posix':
             self.finalize_unix()
         else:
@@ -404,6 +412,48 @@ def dump_dirs(self, msg):
                 val = getattr(self, opt_name)
             log.debug("  %s: %s", opt_name, val)
 
+    def _load_schemes(self):
+        """
+        Allow sysconfig and runtime behaviors to alter schemes.
+        """
+
+        try:
+            import sysconfig
+            INSTALL_SCHEMES.update(sysconfig.INSTALL_SCHEMES)
+            return
+        except Exception:
+            pass
+
+        def is_virtualenv():
+            return (
+                hasattr(sys, 'real_prefix') or
+                sys.prefix != sys.base_prefix or
+                'VIRTUAL_ENV' in os.environ
+            )
+
+        # fedora:
+        def is_rpm_build():
+            return 'RPM_BUILD_ROOT' in os.environ
+
+        if not is_virtualenv() and not is_rpm_build():
+            INSTALL_SCHEMES['unix_prefix'] = INSTALL_SCHEMES['unix_local']
+
+        # debian:
+        def is_deb_system():
+            # TODO: how to solicit without an additional parameter to build?
+            return self.install_layout.lower() == 'deb'
+
+        if is_deb_system():
+            INSTALL_SCHEMES['unix_prefix'] = {
+                'purelib': '$base/lib/python3/dist-packages',
+                'platlib': '$platbase/lib/python3/dist-packages',
+                'headers': '$base/include/python$py_version_short/$dist_name',
+                'scripts': '$base/bin',
+                'data'   : '$base',
+            }
+        if not is_virtualenv():
+            INSTALL_SCHEMES['unix_prefix'] = INSTALL_SCHEMES['unix_local']
+
     def finalize_unix(self):
         """Finalizes options for posix platforms."""
         if self.install_base is not None or self.install_platbase is not None:

From 87c3a984741ab91023a86be28f7145fbf4901862 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Tue, 21 Sep 2021 14:10:17 -0400
Subject: [PATCH 02/16] Only catch relevant exeptions.

Co-authored-by: Petr Viktorin <encukou@gmail.com>
---
 distutils/command/install.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index f3dce84b..80165778 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -421,7 +421,7 @@ def _load_schemes(self):
             import sysconfig
             INSTALL_SCHEMES.update(sysconfig.INSTALL_SCHEMES)
             return
-        except Exception:
+        except (ImportError, AttributeError):
             pass
 
         def is_virtualenv():

From fbbc98f569c135add8f95a5a1e2f8f6b7ad53750 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Tue, 21 Sep 2021 14:23:22 -0400
Subject: [PATCH 03/16] Remove is_rpm_build, unneeded.

---
 distutils/command/install.py | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 80165778..15c21df5 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -431,11 +431,7 @@ def is_virtualenv():
                 'VIRTUAL_ENV' in os.environ
             )
 
-        # fedora:
-        def is_rpm_build():
-            return 'RPM_BUILD_ROOT' in os.environ
-
-        if not is_virtualenv() and not is_rpm_build():
+        if not is_virtualenv():
             INSTALL_SCHEMES['unix_prefix'] = INSTALL_SCHEMES['unix_local']
 
         # debian:

From 968d2984b116fe1c4e556ebd811ec0e0420307b3 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Tue, 21 Sep 2021 14:44:34 -0400
Subject: [PATCH 04/16] In _load_schemes, actually return the schemes and avoid
 mutating the global state.

---
 distutils/command/install.py | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 15c21df5..796d3791 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -285,11 +285,10 @@ 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}")
 
-        self._load_schemes()
         if os.name == 'posix':
             self.finalize_unix()
         else:
@@ -417,10 +416,12 @@ def _load_schemes(self):
         Allow sysconfig and runtime behaviors to alter schemes.
         """
 
+        schemes = dict(INSTALL_SCHEMES)
+
         try:
             import sysconfig
-            INSTALL_SCHEMES.update(sysconfig.INSTALL_SCHEMES)
-            return
+            schemes.update(sysconfig.INSTALL_SCHEMES)
+            return schemes
         except (ImportError, AttributeError):
             pass
 
@@ -432,7 +433,7 @@ def is_virtualenv():
             )
 
         if not is_virtualenv():
-            INSTALL_SCHEMES['unix_prefix'] = INSTALL_SCHEMES['unix_local']
+            schemes['unix_prefix'] = schemes['unix_local']
 
         # debian:
         def is_deb_system():
@@ -440,7 +441,7 @@ def is_deb_system():
             return self.install_layout.lower() == 'deb'
 
         if is_deb_system():
-            INSTALL_SCHEMES['unix_prefix'] = {
+            schemes['unix_prefix'] = {
                 'purelib': '$base/lib/python3/dist-packages',
                 'platlib': '$platbase/lib/python3/dist-packages',
                 'headers': '$base/include/python$py_version_short/$dist_name',
@@ -448,7 +449,9 @@ def is_deb_system():
                 'data'   : '$base',
             }
         if not is_virtualenv():
-            INSTALL_SCHEMES['unix_prefix'] = INSTALL_SCHEMES['unix_local']
+            schemes['unix_prefix'] = schemes['unix_local']
+
+        return schemes
 
     def finalize_unix(self):
         """Finalizes options for posix platforms."""
@@ -521,7 +524,7 @@ def select_scheme(self, name):
                 name = 'pypy_nt'
             else:
                 name = 'pypy'
-        scheme = INSTALL_SCHEMES[name]
+        scheme = self._load_schemes()[name]
         for key in SCHEME_KEYS:
             attrname = 'install_' + key
             if getattr(self, attrname) is None:

From da44ac095ad1a611959082df5e3f934772b5041c Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Tue, 21 Sep 2021 14:53:00 -0400
Subject: [PATCH 05/16] Remove 'unix_local' install scheme.

---
 distutils/command/install.py | 19 -------------------
 1 file changed, 19 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 796d3791..b005c3a9 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -35,13 +35,6 @@
         'scripts': '$base/bin',
         'data'   : '$base',
         },
-    'unix_local': {
-        'purelib': '$base/local/lib/python$py_version_short/site-packages',
-        'platlib': '$platbase/local/$platlibdir/python$py_version_short/site-packages',
-        'headers': '$base/local/include/python$py_version_short$abiflags/$dist_name',
-        'scripts': '$base/local/bin',
-        'data'   : '$base/local',
-        },
     'unix_home': {
         'purelib': '$base/lib/python',
         'platlib': '$base/$platlibdir/python',
@@ -425,16 +418,6 @@ def _load_schemes(self):
         except (ImportError, AttributeError):
             pass
 
-        def is_virtualenv():
-            return (
-                hasattr(sys, 'real_prefix') or
-                sys.prefix != sys.base_prefix or
-                'VIRTUAL_ENV' in os.environ
-            )
-
-        if not is_virtualenv():
-            schemes['unix_prefix'] = schemes['unix_local']
-
         # debian:
         def is_deb_system():
             # TODO: how to solicit without an additional parameter to build?
@@ -448,8 +431,6 @@ def is_deb_system():
                 'scripts': '$base/bin',
                 'data'   : '$base',
             }
-        if not is_virtualenv():
-            schemes['unix_prefix'] = schemes['unix_local']
 
         return schemes
 

From dcafd577d3bc0a5a87e3278d976bea0ca4b43084 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Tue, 21 Sep 2021 14:54:59 -0400
Subject: [PATCH 06/16] Remove special casing for Debian. Instead, Debian
 should make sure the schemes are updated in sysconfig.

---
 distutils/command/install.py | 17 +----------------
 1 file changed, 1 insertion(+), 16 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index b005c3a9..848388bb 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -406,7 +406,7 @@ def dump_dirs(self, msg):
 
     def _load_schemes(self):
         """
-        Allow sysconfig and runtime behaviors to alter schemes.
+        Allow sysconfig to alter schemes.
         """
 
         schemes = dict(INSTALL_SCHEMES)
@@ -414,24 +414,9 @@ def _load_schemes(self):
         try:
             import sysconfig
             schemes.update(sysconfig.INSTALL_SCHEMES)
-            return schemes
         except (ImportError, AttributeError):
             pass
 
-        # debian:
-        def is_deb_system():
-            # TODO: how to solicit without an additional parameter to build?
-            return self.install_layout.lower() == 'deb'
-
-        if is_deb_system():
-            schemes['unix_prefix'] = {
-                'purelib': '$base/lib/python3/dist-packages',
-                'platlib': '$platbase/lib/python3/dist-packages',
-                'headers': '$base/include/python$py_version_short/$dist_name',
-                'scripts': '$base/bin',
-                'data'   : '$base',
-            }
-
         return schemes
 
     def finalize_unix(self):

From 044f77190bb457f35222044e5a455cfb11a4455e Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Tue, 21 Sep 2021 20:53:59 -0400
Subject: [PATCH 07/16] Replace instance method with global function.

---
 distutils/command/install.py | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 848388bb..026c609a 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -84,6 +84,22 @@
 SCHEME_KEYS = ('purelib', 'platlib', 'headers', 'scripts', 'data')
 
 
+def _load_schemes():
+    """
+    Extend default schemes with schemes from sysconfig.
+    """
+
+    schemes = dict(INSTALL_SCHEMES)
+
+    try:
+        import sysconfig
+        schemes.update(sysconfig.INSTALL_SCHEMES)
+    except (ImportError, AttributeError):
+        pass
+
+    return schemes
+
+
 class install(Command):
 
     description = "install everything from build directory"
@@ -404,21 +420,6 @@ def dump_dirs(self, msg):
                 val = getattr(self, opt_name)
             log.debug("  %s: %s", opt_name, val)
 
-    def _load_schemes(self):
-        """
-        Allow sysconfig to alter schemes.
-        """
-
-        schemes = dict(INSTALL_SCHEMES)
-
-        try:
-            import sysconfig
-            schemes.update(sysconfig.INSTALL_SCHEMES)
-        except (ImportError, AttributeError):
-            pass
-
-        return schemes
-
     def finalize_unix(self):
         """Finalizes options for posix platforms."""
         if self.install_base is not None or self.install_platbase is not None:
@@ -490,7 +491,7 @@ def select_scheme(self, name):
                 name = 'pypy_nt'
             else:
                 name = 'pypy'
-        scheme = self._load_schemes()[name]
+        scheme = _load_schemes()[name]
         for key in SCHEME_KEYS:
             attrname = 'install_' + key
             if getattr(self, attrname) is None:

From 1d7c74836b725af874f975503568053f0b95e26c Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sat, 6 Nov 2021 11:00:07 -0400
Subject: [PATCH 08/16] Prefer public APIs for sysconfig schemes.

---
 distutils/command/install.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 026c609a..0db71e94 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -93,7 +93,11 @@ def _load_schemes():
 
     try:
         import sysconfig
-        schemes.update(sysconfig.INSTALL_SCHEMES)
+        sysconfig_schemes = {
+            scheme: sysconfig.get_paths(scheme, expand=False)
+            for scheme in sysconfig.get_scheme_names()
+        }
+        schemes.update(sysconfig_schemes)
     except (ImportError, AttributeError):
         pass
 

From 28e643959a4208f86fb3b37ae9b78eb07ad5b6d5 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sat, 6 Nov 2021 11:01:18 -0400
Subject: [PATCH 09/16] Prefer contextlib.suppress to except/pass

---
 distutils/command/install.py | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 0db71e94..b1876748 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -4,6 +4,7 @@
 
 import sys
 import os
+import contextlib
 
 from distutils import log
 from distutils.core import Command
@@ -91,15 +92,13 @@ def _load_schemes():
 
     schemes = dict(INSTALL_SCHEMES)
 
-    try:
+    with contextlib.suppress(ImportError, AttributeError):
         import sysconfig
         sysconfig_schemes = {
             scheme: sysconfig.get_paths(scheme, expand=False)
             for scheme in sysconfig.get_scheme_names()
         }
         schemes.update(sysconfig_schemes)
-    except (ImportError, AttributeError):
-        pass
 
     return schemes
 

From e4466cd3436c6b331fac85bd28d1fdaa658772f7 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sat, 6 Nov 2021 13:02:35 -0400
Subject: [PATCH 10/16] Rename 'headers' to 'include' to match sysconfig.

---
 distutils/command/install.py | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index b1876748..1267a51e 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -23,7 +23,7 @@
 WINDOWS_SCHEME = {
     'purelib': '$base/Lib/site-packages',
     'platlib': '$base/Lib/site-packages',
-    'headers': '$base/Include/$dist_name',
+    'include': '$base/Include/$dist_name',
     'scripts': '$base/Scripts',
     'data'   : '$base',
 }
@@ -32,14 +32,14 @@
     'unix_prefix': {
         'purelib': '$base/lib/python$py_version_short/site-packages',
         'platlib': '$platbase/$platlibdir/python$py_version_short/site-packages',
-        'headers': '$base/include/python$py_version_short$abiflags/$dist_name',
+        'include': '$base/include/python$py_version_short$abiflags/$dist_name',
         'scripts': '$base/bin',
         'data'   : '$base',
         },
     'unix_home': {
         'purelib': '$base/lib/python',
         'platlib': '$base/$platlibdir/python',
-        'headers': '$base/include/python/$dist_name',
+        'include': '$base/include/python/$dist_name',
         'scripts': '$base/bin',
         'data'   : '$base',
         },
@@ -47,14 +47,14 @@
     'pypy': {
         'purelib': '$base/site-packages',
         'platlib': '$base/site-packages',
-        'headers': '$base/include/$dist_name',
+        'include': '$base/include/$dist_name',
         'scripts': '$base/bin',
         'data'   : '$base',
         },
     'pypy_nt': {
         'purelib': '$base/site-packages',
         'platlib': '$base/site-packages',
-        'headers': '$base/include/$dist_name',
+        'include': '$base/include/$dist_name',
         'scripts': '$base/Scripts',
         'data'   : '$base',
         },
@@ -65,7 +65,7 @@
     INSTALL_SCHEMES['nt_user'] = {
         'purelib': '$usersite',
         'platlib': '$usersite',
-        'headers': '$userbase/Python$py_version_nodot/Include/$dist_name',
+        'include': '$userbase/Python$py_version_nodot/Include/$dist_name',
         'scripts': '$userbase/Python$py_version_nodot/Scripts',
         'data'   : '$userbase',
         }
@@ -73,7 +73,7 @@
     INSTALL_SCHEMES['unix_user'] = {
         'purelib': '$usersite',
         'platlib': '$usersite',
-        'headers':
+        'include':
             '$userbase/include/python$py_version_short$abiflags/$dist_name',
         'scripts': '$userbase/bin',
         'data'   : '$userbase',
@@ -82,7 +82,7 @@
 # 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')
+SCHEME_KEYS = ('purelib', 'platlib', 'include', 'scripts', 'data')
 
 
 def _load_schemes():
@@ -198,7 +198,7 @@ def initialize_options(self):
         # that installation scheme.
         self.install_purelib = None     # for pure module distributions
         self.install_platlib = None     # non-pure (dists w/ extensions)
-        self.install_headers = None     # for C/C++ headers
+        self.install_include = None     # for C/C++ headers
         self.install_lib = None         # set to either purelib or platlib
         self.install_scripts = None
         self.install_data = None
@@ -247,6 +247,10 @@ def initialize_options(self):
 
         self.record = None
 
+    @property
+    def install_headers(self):
+        # for compatibility
+        return self.install_include
 
     # -- Option finalizing methods -------------------------------------
     # (This is rather more involved than for most commands,
@@ -376,7 +380,7 @@ def finalize_options(self):
         # Convert directories from Unix /-separated syntax to the local
         # convention.
         self.convert_paths('lib', 'purelib', 'platlib',
-                           'scripts', 'data', 'headers',
+                           'scripts', 'data', 'include',
                            'userbase', 'usersite')
 
         # Deprecated
@@ -392,7 +396,7 @@ def finalize_options(self):
         # dirs relative to it.
         if self.root is not None:
             self.change_roots('libbase', 'lib', 'purelib', 'platlib',
-                              'scripts', 'data', 'headers')
+                              'scripts', 'data', 'include')
 
         self.dump_dirs("after prepending root")
 
@@ -429,7 +433,7 @@ def finalize_unix(self):
             if ((self.install_lib is None and
                  self.install_purelib is None and
                  self.install_platlib is None) or
-                self.install_headers is None or
+                self.install_include is None or
                 self.install_scripts is None or
                 self.install_data is None):
                 raise DistutilsOptionError(
@@ -517,7 +521,7 @@ def expand_basedirs(self):
     def expand_dirs(self):
         """Calls `os.path.expanduser` on install dirs."""
         self._expand_attrs(['install_purelib', 'install_platlib',
-                            'install_lib', 'install_headers',
+                            'install_lib', 'install_include',
                             'install_scripts', 'install_data',])
 
     def convert_paths(self, *names):

From af44971ccc28f5151c896eec66b801944cf8545b Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sat, 6 Nov 2021 13:22:51 -0400
Subject: [PATCH 11/16] Replace shell/Perl-style variables in install schemes
 with format-style.

---
 distutils/command/install.py | 70 ++++++++++++++++++------------------
 distutils/util.py            | 37 ++++++++++++-------
 2 files changed, 60 insertions(+), 47 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 1267a51e..0f4ff70c 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -21,62 +21,62 @@
 HAS_USER_SITE = True
 
 WINDOWS_SCHEME = {
-    'purelib': '$base/Lib/site-packages',
-    'platlib': '$base/Lib/site-packages',
-    'include': '$base/Include/$dist_name',
-    'scripts': '$base/Scripts',
-    'data'   : '$base',
+    'purelib': '{base}/Lib/site-packages',
+    'platlib': '{base}/Lib/site-packages',
+    'include': '{base}/Include/{dist_name}',
+    'scripts': '{base}/Scripts',
+    'data'   : '{base}',
 }
 
 INSTALL_SCHEMES = {
     'unix_prefix': {
-        'purelib': '$base/lib/python$py_version_short/site-packages',
-        'platlib': '$platbase/$platlibdir/python$py_version_short/site-packages',
-        'include': '$base/include/python$py_version_short$abiflags/$dist_name',
-        'scripts': '$base/bin',
-        'data'   : '$base',
+        'purelib': '{base}/lib/python{py_version_short}/site-packages',
+        'platlib': '{platbase}/{platlibdir}/python{py_version_short}/site-packages',
+        'include': '{base}/include/python{py_version_short}{abiflags}/{dist_name}',
+        'scripts': '{base}/bin',
+        'data'   : '{base}',
         },
     'unix_home': {
-        'purelib': '$base/lib/python',
-        'platlib': '$base/$platlibdir/python',
-        'include': '$base/include/python/$dist_name',
-        'scripts': '$base/bin',
-        'data'   : '$base',
+        'purelib': '{base}/lib/python',
+        'platlib': '{base}/{platlibdir}/python',
+        'include': '{base}/include/python/{dist_name}',
+        'scripts': '{base}/bin',
+        'data'   : '{base}',
         },
     'nt': WINDOWS_SCHEME,
     'pypy': {
-        'purelib': '$base/site-packages',
-        'platlib': '$base/site-packages',
-        'include': '$base/include/$dist_name',
-        'scripts': '$base/bin',
-        'data'   : '$base',
+        'purelib': '{base}/site-packages',
+        'platlib': '{base}/site-packages',
+        'include': '{base}/include/{dist_name}',
+        'scripts': '{base}/bin',
+        'data'   : '{base}',
         },
     'pypy_nt': {
-        'purelib': '$base/site-packages',
-        'platlib': '$base/site-packages',
-        'include': '$base/include/$dist_name',
-        'scripts': '$base/Scripts',
-        'data'   : '$base',
+        'purelib': '{base}/site-packages',
+        'platlib': '{base}/site-packages',
+        'include': '{base}/include/{dist_name}',
+        'scripts': '{base}/Scripts',
+        'data'   : '{base}',
         },
     }
 
 # user site schemes
 if HAS_USER_SITE:
     INSTALL_SCHEMES['nt_user'] = {
-        'purelib': '$usersite',
-        'platlib': '$usersite',
-        'include': '$userbase/Python$py_version_nodot/Include/$dist_name',
-        'scripts': '$userbase/Python$py_version_nodot/Scripts',
-        'data'   : '$userbase',
+        'purelib': '{usersite}',
+        'platlib': '{usersite}',
+        'include': '{userbase}/Python{py_version_nodot}/Include/{dist_name}',
+        'scripts': '{userbase}/Python{py_version_nodot}/Scripts',
+        'data'   : '{userbase}',
         }
 
     INSTALL_SCHEMES['unix_user'] = {
-        'purelib': '$usersite',
-        'platlib': '$usersite',
+        'purelib': '{usersite}',
+        'platlib': '{usersite}',
         'include':
-            '$userbase/include/python$py_version_short$abiflags/$dist_name',
-        'scripts': '$userbase/bin',
-        'data'   : '$userbase',
+            '{userbase}/include/python{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
diff --git a/distutils/util.py b/distutils/util.py
index f5aca794..81d6869f 100644
--- a/distutils/util.py
+++ b/distutils/util.py
@@ -187,30 +187,43 @@ 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)
 
 # 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,

From f1a6ea01ffef107b0ff20aea5e6b5716608bde2a Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sat, 6 Nov 2021 13:36:37 -0400
Subject: [PATCH 12/16] Clean up 'invalid variable'. A KeyError already
 includes the quotes when rendered.

---
 distutils/util.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/distutils/util.py b/distutils/util.py
index d9916a0a..ac6d446d 100644
--- a/distutils/util.py
+++ b/distutils/util.py
@@ -257,7 +257,7 @@ def subst_vars (s, local_vars):
     try:
         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 ()
 

From 341c9087e64dabaaef2718e229fd940c78d9b86f Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sat, 6 Nov 2021 13:47:22 -0400
Subject: [PATCH 13/16] Copy installed_base from sysconfig.get_config_vars.

---
 distutils/command/install.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 8161aa9e..23d48ba3 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -5,6 +5,7 @@
 import sys
 import os
 import contextlib
+import sysconfig
 
 from distutils import log
 from distutils.core import Command
@@ -92,8 +93,7 @@ def _load_schemes():
 
     schemes = dict(INSTALL_SCHEMES)
 
-    with contextlib.suppress(ImportError, AttributeError):
-        import sysconfig
+    with contextlib.suppress(AttributeError):
         sysconfig_schemes = {
             scheme: sysconfig.get_paths(scheme, expand=False)
             for scheme in sysconfig.get_scheme_names()
@@ -102,6 +102,7 @@ def _load_schemes():
 
     return schemes
 
+
 def _get_implementation():
     if hasattr(sys, 'pypy_version_info'):
         return 'PyPy'
@@ -358,6 +359,8 @@ 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

From 5c5aed1004472ecec994620fec43743f0528a254 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sat, 6 Nov 2021 18:53:22 -0400
Subject: [PATCH 14/16] Prefer 'posix_*' to 'unix_*'

---
 distutils/command/install.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 23d48ba3..6ba07ffd 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -457,10 +457,10 @@ 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:
@@ -476,7 +476,7 @@ 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"""
@@ -488,7 +488,7 @@ 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)

From 69b850303420cf47d41d6e6f47ed07a3e2dd4516 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Fri, 12 Nov 2021 15:46:00 -0500
Subject: [PATCH 15/16] Revert "Rename 'headers' to 'include' to match
 sysconfig."

This reverts commit e4466cd3436c6b331fac85bd28d1fdaa658772f7.
---
 distutils/command/install.py | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index 6ba07ffd..dd313d8a 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -24,7 +24,7 @@
 WINDOWS_SCHEME = {
     'purelib': '{base}/Lib/site-packages',
     'platlib': '{base}/Lib/site-packages',
-    'include': '{base}/Include/{dist_name}',
+    'headers': '{base}/Include/{dist_name}',
     'scripts': '{base}/Scripts',
     'data'   : '{base}',
 }
@@ -33,14 +33,14 @@
     'unix_prefix': {
         'purelib': '{base}/lib/{implementation_lower}{py_version_short}/site-packages',
         'platlib': '{platbase}/{platlibdir}/{implementation_lower}{py_version_short}/site-packages',
-        'include': '{base}/include/{implementation_lower}{py_version_short}{abiflags}/{dist_name}',
+        '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}',
-        'include': '{base}/include/{implementation_lower}/{dist_name}',
+        'headers': '{base}/include/{implementation_lower}/{dist_name}',
         'scripts': '{base}/bin',
         'data'   : '{base}',
         },
@@ -48,14 +48,14 @@
     'pypy': {
         'purelib': '{base}/site-packages',
         'platlib': '{base}/site-packages',
-        'include': '{base}/include/{dist_name}',
+        'headers': '{base}/include/{dist_name}',
         'scripts': '{base}/bin',
         'data'   : '{base}',
         },
     'pypy_nt': {
         'purelib': '{base}/site-packages',
         'platlib': '{base}/site-packages',
-        'include': '{base}/include/{dist_name}',
+        'headers': '{base}/include/{dist_name}',
         'scripts': '{base}/Scripts',
         'data'   : '{base}',
         },
@@ -66,7 +66,7 @@
     INSTALL_SCHEMES['nt_user'] = {
         'purelib': '{usersite}',
         'platlib': '{usersite}',
-        'include': '{userbase}/{implementation}{py_version_nodot}/Include/{dist_name}',
+        'headers': '{userbase}/{implementation}{py_version_nodot}/Include/{dist_name}',
         'scripts': '{userbase}/{implementation}{py_version_nodot}/Scripts',
         'data'   : '{userbase}',
         }
@@ -74,7 +74,7 @@
     INSTALL_SCHEMES['unix_user'] = {
         'purelib': '{usersite}',
         'platlib': '{usersite}',
-        'include':
+        'headers':
             '{userbase}/include/{implementation_lower}{py_version_short}{abiflags}/{dist_name}',
         'scripts': '{userbase}/bin',
         'data'   : '{userbase}',
@@ -83,7 +83,7 @@
 # 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', 'include', 'scripts', 'data')
+SCHEME_KEYS = ('purelib', 'platlib', 'headers', 'scripts', 'data')
 
 
 def _load_schemes():
@@ -205,7 +205,7 @@ def initialize_options(self):
         # that installation scheme.
         self.install_purelib = None     # for pure module distributions
         self.install_platlib = None     # non-pure (dists w/ extensions)
-        self.install_include = None     # for C/C++ headers
+        self.install_headers = None     # for C/C++ headers
         self.install_lib = None         # set to either purelib or platlib
         self.install_scripts = None
         self.install_data = None
@@ -254,10 +254,6 @@ def initialize_options(self):
 
         self.record = None
 
-    @property
-    def install_headers(self):
-        # for compatibility
-        return self.install_include
 
     # -- Option finalizing methods -------------------------------------
     # (This is rather more involved than for most commands,
@@ -391,7 +387,7 @@ def finalize_options(self):
         # Convert directories from Unix /-separated syntax to the local
         # convention.
         self.convert_paths('lib', 'purelib', 'platlib',
-                           'scripts', 'data', 'include',
+                           'scripts', 'data', 'headers',
                            'userbase', 'usersite')
 
         # Deprecated
@@ -407,7 +403,7 @@ def finalize_options(self):
         # dirs relative to it.
         if self.root is not None:
             self.change_roots('libbase', 'lib', 'purelib', 'platlib',
-                              'scripts', 'data', 'include')
+                              'scripts', 'data', 'headers')
 
         self.dump_dirs("after prepending root")
 
@@ -444,7 +440,7 @@ def finalize_unix(self):
             if ((self.install_lib is None and
                  self.install_purelib is None and
                  self.install_platlib is None) or
-                self.install_include is None or
+                self.install_headers is None or
                 self.install_scripts is None or
                 self.install_data is None):
                 raise DistutilsOptionError(
@@ -533,7 +529,7 @@ def expand_basedirs(self):
     def expand_dirs(self):
         """Calls `os.path.expanduser` on install dirs."""
         self._expand_attrs(['install_purelib', 'install_platlib',
-                            'install_lib', 'install_include',
+                            'install_lib', 'install_headers',
                             'install_scripts', 'install_data',])
 
     def convert_paths(self, *names):

From 342e02e7a4dbedf0e3a04c4d2d213b5340d56010 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Fri, 12 Nov 2021 16:06:47 -0500
Subject: [PATCH 16/16] Rename 'posix' to 'unix' to match sysconfig. Merge both
 definitions with sysconfig.

---
 distutils/command/install.py    | 30 +++++++++++++++++++-----------
 distutils/tests/test_install.py |  2 +-
 2 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/distutils/command/install.py b/distutils/command/install.py
index dd313d8a..c756b6db 100644
--- a/distutils/command/install.py
+++ b/distutils/command/install.py
@@ -6,6 +6,7 @@
 import os
 import contextlib
 import sysconfig
+import itertools
 
 from distutils import log
 from distutils.core import Command
@@ -30,14 +31,14 @@
 }
 
 INSTALL_SCHEMES = {
-    'unix_prefix': {
+    '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': {
+    'posix_home': {
         'purelib': '{base}/lib/{implementation_lower}',
         'platlib': '{base}/{platlibdir}/{implementation_lower}',
         'headers': '{base}/include/{implementation_lower}/{dist_name}',
@@ -71,7 +72,7 @@
         'data'   : '{userbase}',
         }
 
-    INSTALL_SCHEMES['unix_user'] = {
+    INSTALL_SCHEMES['posix_user'] = {
         'purelib': '{usersite}',
         'platlib': '{usersite}',
         'headers':
@@ -86,21 +87,28 @@
 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.
     """
 
-    schemes = dict(INSTALL_SCHEMES)
+    sysconfig_schemes = _load_sysconfig_schemes() or {}
 
-    with contextlib.suppress(AttributeError):
-        sysconfig_schemes = {
-            scheme: sysconfig.get_paths(scheme, expand=False)
-            for scheme in sysconfig.get_scheme_names()
+    return {
+        scheme: {
+            **INSTALL_SCHEMES.get(scheme, {}),
+            **sysconfig_schemes.get(scheme, {}),
         }
-        schemes.update(sysconfig_schemes)
-
-    return schemes
+        for scheme in set(itertools.chain(INSTALL_SCHEMES, sysconfig_schemes))
+    }
 
 
 def _get_implementation():
diff --git a/distutils/tests/test_install.py b/distutils/tests/test_install.py
index eb684a09..cce973dc 100644
--- a/distutils/tests/test_install.py
+++ b/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'})