GH-103480: make sysconfig a package (GH-110785)

3 files changed, 248 insertions, 229 deletions

diff --git a/Lib/sysconfig.py b/Lib/sysconfig/__init__.py
index edfe451..68d30c0 100644
--- a/Lib/sysconfig.py
+++ b/Lib/sysconfig/__init__.py
@@ -180,12 +180,6 @@ _CONFIG_VARS = None
 _CONFIG_VARS_INITIALIZED = False
 _USER_BASE = None
 
-# Regexes needed for parsing Makefile (and similar syntaxes,
-# like old-style Setup files).
-_variable_rx = r"([a-zA-Z][a-zA-Z0-9_]+)\s*=\s*(.*)"
-_findvar1_rx = r"\$\(([A-Za-z][A-Za-z0-9_]*)\)"
-_findvar2_rx = r"\${([A-Za-z][A-Za-z0-9_]*)}"
-
 
 def _safe_realpath(path):
     try:
@@ -317,134 +311,6 @@ def get_default_scheme():
     return get_preferred_scheme('prefix')
 
 
-def _parse_makefile(filename, vars=None, keep_unresolved=True):
-    """Parse a Makefile-style file.
-
-    A dictionary containing name/value pairs is returned.  If an
-    optional dictionary is passed in as the second argument, it is
-    used instead of a new dictionary.
-    """
-    import re
-
-    if vars is None:
-        vars = {}
-    done = {}
-    notdone = {}
-
-    with open(filename, encoding=sys.getfilesystemencoding(),
-              errors="surrogateescape") as f:
-        lines = f.readlines()
-
-    for line in lines:
-        if line.startswith('#') or line.strip() == '':
-            continue
-        m = re.match(_variable_rx, line)
-        if m:
-            n, v = m.group(1, 2)
-            v = v.strip()
-            # `$$' is a literal `$' in make
-            tmpv = v.replace('$$', '')
-
-            if "$" in tmpv:
-                notdone[n] = v
-            else:
-                try:
-                    if n in _ALWAYS_STR:
-                        raise ValueError
-
-                    v = int(v)
-                except ValueError:
-                    # insert literal `$'
-                    done[n] = v.replace('$$', '$')
-                else:
-                    done[n] = v
-
-    # do variable interpolation here
-    variables = list(notdone.keys())
-
-    # Variables with a 'PY_' prefix in the makefile. These need to
-    # be made available without that prefix through sysconfig.
-    # Special care is needed to ensure that variable expansion works, even
-    # if the expansion uses the name without a prefix.
-    renamed_variables = ('CFLAGS', 'LDFLAGS', 'CPPFLAGS')
-
-    while len(variables) > 0:
-        for name in tuple(variables):
-            value = notdone[name]
-            m1 = re.search(_findvar1_rx, value)
-            m2 = re.search(_findvar2_rx, value)
-            if m1 and m2:
-                m = m1 if m1.start() < m2.start() else m2
-            else:
-                m = m1 if m1 else m2
-            if m is not None:
-                n = m.group(1)
-                found = True
-                if n in done:
-                    item = str(done[n])
-                elif n in notdone:
-                    # get it on a subsequent round
-                    found = False
-                elif n in os.environ:
-                    # do it like make: fall back to environment
-                    item = os.environ[n]
-
-                elif n in renamed_variables:
-                    if (name.startswith('PY_') and
-                        name[3:] in renamed_variables):
-                        item = ""
-
-                    elif 'PY_' + n in notdone:
-                        found = False
-
-                    else:
-                        item = str(done['PY_' + n])
-
-                else:
-                    done[n] = item = ""
-
-                if found:
-                    after = value[m.end():]
-                    value = value[:m.start()] + item + after
-                    if "$" in after:
-                        notdone[name] = value
-                    else:
-                        try:
-                            if name in _ALWAYS_STR:
-                                raise ValueError
-                            value = int(value)
-                        except ValueError:
-                            done[name] = value.strip()
-                        else:
-                            done[name] = value
-                        variables.remove(name)
-
-                        if name.startswith('PY_') \
-                        and name[3:] in renamed_variables:
-
-                            name = name[3:]
-                            if name not in done:
-                                done[name] = value
-
-            else:
-                # Adds unresolved variables to the done dict.
-                # This is disabled when called from distutils.sysconfig
-                if keep_unresolved:
-                    done[name] = value
-                # bogus variable reference (e.g. "prefix=$/opt/python");
-                # just drop it since we can't deal
-                variables.remove(name)
-
-    # strip spurious spaces
-    for k, v in done.items():
-        if isinstance(v, str):
-            done[k] = v.strip()
-
-    # save the results in the global dictionary
-    vars.update(done)
-    return vars
-
-
 def get_makefile_filename():
     """Return the path of the Makefile."""
     if _PYTHON_BUILD:
@@ -465,74 +331,6 @@ def _get_sysconfigdata_name():
         f'_sysconfigdata_{sys.abiflags}_{sys.platform}_{multiarch}',
     )
 
-def _print_config_dict(d, stream):
-    print ("{", file=stream)
-    for k, v in sorted(d.items()):
-        print(f"    {k!r}: {v!r},", file=stream)
-    print ("}", file=stream)
-
-def _generate_posix_vars():
-    """Generate the Python module containing build-time variables."""
-    vars = {}
-    # load the installed Makefile:
-    makefile = get_makefile_filename()
-    try:
-        _parse_makefile(makefile, vars)
-    except OSError as e:
-        msg = f"invalid Python installation: unable to open {makefile}"
-        if hasattr(e, "strerror"):
-            msg = f"{msg} ({e.strerror})"
-        raise OSError(msg)
-    # load the installed pyconfig.h:
-    config_h = get_config_h_filename()
-    try:
-        with open(config_h, encoding="utf-8") as f:
-            parse_config_h(f, vars)
-    except OSError as e:
-        msg = f"invalid Python installation: unable to open {config_h}"
-        if hasattr(e, "strerror"):
-            msg = f"{msg} ({e.strerror})"
-        raise OSError(msg)
-    # On AIX, there are wrong paths to the linker scripts in the Makefile
-    # -- these paths are relative to the Python source, but when installed
-    # the scripts are in another directory.
-    if _PYTHON_BUILD:
-        vars['BLDSHARED'] = vars['LDSHARED']
-
-    # There's a chicken-and-egg situation on OS X with regards to the
-    # _sysconfigdata module after the changes introduced by #15298:
-    # get_config_vars() is called by get_platform() as part of the
-    # `make pybuilddir.txt` target -- which is a precursor to the
-    # _sysconfigdata.py module being constructed.  Unfortunately,
-    # get_config_vars() eventually calls _init_posix(), which attempts
-    # to import _sysconfigdata, which we won't have built yet.  In order
-    # for _init_posix() to work, if we're on Darwin, just mock up the
-    # _sysconfigdata module manually and populate it with the build vars.
-    # This is more than sufficient for ensuring the subsequent call to
-    # get_platform() succeeds.
-    name = _get_sysconfigdata_name()
-    if 'darwin' in sys.platform:
-        import types
-        module = types.ModuleType(name)
-        module.build_time_vars = vars
-        sys.modules[name] = module
-
-    pybuilddir = f'build/lib.{get_platform()}-{_PY_VERSION_SHORT}'
-    if hasattr(sys, "gettotalrefcount"):
-        pybuilddir += '-pydebug'
-    os.makedirs(pybuilddir, exist_ok=True)
-    destfile = os.path.join(pybuilddir, name + '.py')
-
-    with open(destfile, 'w', encoding='utf8') as f:
-        f.write('# system configuration generated and used by'
-                ' the sysconfig module\n')
-        f.write('build_time_vars = ')
-        _print_config_dict(vars, stream=f)
-
-    # Create file used for sys.path fixup -- see Modules/getpath.c
-    with open('pybuilddir.txt', 'w', encoding='utf8') as f:
-        f.write(pybuilddir)
-
 def _init_posix(vars):
     """Initialize the module as appropriate for POSIX systems."""
     # _sysconfigdata is generated at build time, see _generate_posix_vars()
@@ -857,28 +655,3 @@ def expand_makefile_vars(s, vars):
         else:
             break
     return s
-
-
-def _print_dict(title, data):
-    for index, (key, value) in enumerate(sorted(data.items())):
-        if index == 0:
-            print(f'{title}: ')
-        print(f'\t{key} = "{value}"')
-
-
-def _main():
-    """Display all information sysconfig detains."""
-    if '--generate-posix-vars' in sys.argv:
-        _generate_posix_vars()
-        return
-    print(f'Platform: "{get_platform()}"')
-    print(f'Python version: "{get_python_version()}"')
-    print(f'Current installation scheme: "{get_default_scheme()}"')
-    print()
-    _print_dict('Paths', get_paths())
-    print()
-    _print_dict('Variables', get_config_vars())
-
-
-if __name__ == '__main__':
-    _main()
diff --git a/Lib/sysconfig/__main__.py b/Lib/sysconfig/__main__.py
new file mode 100644
index 0000000..e0c3756
--- /dev/null
+++ b/Lib/sysconfig/__main__.py
@@ -0,0 +1,245 @@
+import os
+import sys
+from sysconfig import (
+    _ALWAYS_STR,
+    _PYTHON_BUILD,
+    _get_sysconfigdata_name,
+    get_config_h_filename,
+    get_config_vars,
+    get_default_scheme,
+    get_makefile_filename,
+    get_paths,
+    get_platform,
+    get_python_version,
+    parse_config_h,
+)
+
+
+# Regexes needed for parsing Makefile (and similar syntaxes,
+# like old-style Setup files).
+_variable_rx = r"([a-zA-Z][a-zA-Z0-9_]+)\s*=\s*(.*)"
+_findvar1_rx = r"\$\(([A-Za-z][A-Za-z0-9_]*)\)"
+_findvar2_rx = r"\${([A-Za-z][A-Za-z0-9_]*)}"
+
+
+def _parse_makefile(filename, vars=None, keep_unresolved=True):
+    """Parse a Makefile-style file.
+
+    A dictionary containing name/value pairs is returned.  If an
+    optional dictionary is passed in as the second argument, it is
+    used instead of a new dictionary.
+    """
+    import re
+
+    if vars is None:
+        vars = {}
+    done = {}
+    notdone = {}
+
+    with open(filename, encoding=sys.getfilesystemencoding(),
+              errors="surrogateescape") as f:
+        lines = f.readlines()
+
+    for line in lines:
+        if line.startswith('#') or line.strip() == '':
+            continue
+        m = re.match(_variable_rx, line)
+        if m:
+            n, v = m.group(1, 2)
+            v = v.strip()
+            # `$$' is a literal `$' in make
+            tmpv = v.replace('$$', '')
+
+            if "$" in tmpv:
+                notdone[n] = v
+            else:
+                try:
+                    if n in _ALWAYS_STR:
+                        raise ValueError
+
+                    v = int(v)
+                except ValueError:
+                    # insert literal `$'
+                    done[n] = v.replace('$$', '$')
+                else:
+                    done[n] = v
+
+    # do variable interpolation here
+    variables = list(notdone.keys())
+
+    # Variables with a 'PY_' prefix in the makefile. These need to
+    # be made available without that prefix through sysconfig.
+    # Special care is needed to ensure that variable expansion works, even
+    # if the expansion uses the name without a prefix.
+    renamed_variables = ('CFLAGS', 'LDFLAGS', 'CPPFLAGS')
+
+    while len(variables) > 0:
+        for name in tuple(variables):
+            value = notdone[name]
+            m1 = re.search(_findvar1_rx, value)
+            m2 = re.search(_findvar2_rx, value)
+            if m1 and m2:
+                m = m1 if m1.start() < m2.start() else m2
+            else:
+                m = m1 if m1 else m2
+            if m is not None:
+                n = m.group(1)
+                found = True
+                if n in done:
+                    item = str(done[n])
+                elif n in notdone:
+                    # get it on a subsequent round
+                    found = False
+                elif n in os.environ:
+                    # do it like make: fall back to environment
+                    item = os.environ[n]
+
+                elif n in renamed_variables:
+                    if (name.startswith('PY_') and
+                        name[3:] in renamed_variables):
+                        item = ""
+
+                    elif 'PY_' + n in notdone:
+                        found = False
+
+                    else:
+                        item = str(done['PY_' + n])
+
+                else:
+                    done[n] = item = ""
+
+                if found:
+                    after = value[m.end():]
+                    value = value[:m.start()] + item + after
+                    if "$" in after:
+                        notdone[name] = value
+                    else:
+                        try:
+                            if name in _ALWAYS_STR:
+                                raise ValueError
+                            value = int(value)
+                        except ValueError:
+                            done[name] = value.strip()
+                        else:
+                            done[name] = value
+                        variables.remove(name)
+
+                        if name.startswith('PY_') \
+                        and name[3:] in renamed_variables:
+
+                            name = name[3:]
+                            if name not in done:
+                                done[name] = value
+
+            else:
+                # Adds unresolved variables to the done dict.
+                # This is disabled when called from distutils.sysconfig
+                if keep_unresolved:
+                    done[name] = value
+                # bogus variable reference (e.g. "prefix=$/opt/python");
+                # just drop it since we can't deal
+                variables.remove(name)
+
+    # strip spurious spaces
+    for k, v in done.items():
+        if isinstance(v, str):
+            done[k] = v.strip()
+
+    # save the results in the global dictionary
+    vars.update(done)
+    return vars
+
+
+def _print_config_dict(d, stream):
+    print ("{", file=stream)
+    for k, v in sorted(d.items()):
+        print(f"    {k!r}: {v!r},", file=stream)
+    print ("}", file=stream)
+
+
+def _generate_posix_vars():
+    """Generate the Python module containing build-time variables."""
+    vars = {}
+    # load the installed Makefile:
+    makefile = get_makefile_filename()
+    try:
+        _parse_makefile(makefile, vars)
+    except OSError as e:
+        msg = f"invalid Python installation: unable to open {makefile}"
+        if hasattr(e, "strerror"):
+            msg = f"{msg} ({e.strerror})"
+        raise OSError(msg)
+    # load the installed pyconfig.h:
+    config_h = get_config_h_filename()
+    try:
+        with open(config_h, encoding="utf-8") as f:
+            parse_config_h(f, vars)
+    except OSError as e:
+        msg = f"invalid Python installation: unable to open {config_h}"
+        if hasattr(e, "strerror"):
+            msg = f"{msg} ({e.strerror})"
+        raise OSError(msg)
+    # On AIX, there are wrong paths to the linker scripts in the Makefile
+    # -- these paths are relative to the Python source, but when installed
+    # the scripts are in another directory.
+    if _PYTHON_BUILD:
+        vars['BLDSHARED'] = vars['LDSHARED']
+
+    # There's a chicken-and-egg situation on OS X with regards to the
+    # _sysconfigdata module after the changes introduced by #15298:
+    # get_config_vars() is called by get_platform() as part of the
+    # `make pybuilddir.txt` target -- which is a precursor to the
+    # _sysconfigdata.py module being constructed.  Unfortunately,
+    # get_config_vars() eventually calls _init_posix(), which attempts
+    # to import _sysconfigdata, which we won't have built yet.  In order
+    # for _init_posix() to work, if we're on Darwin, just mock up the
+    # _sysconfigdata module manually and populate it with the build vars.
+    # This is more than sufficient for ensuring the subsequent call to
+    # get_platform() succeeds.
+    name = _get_sysconfigdata_name()
+    if 'darwin' in sys.platform:
+        import types
+        module = types.ModuleType(name)
+        module.build_time_vars = vars
+        sys.modules[name] = module
+
+    pybuilddir = f'build/lib.{get_platform()}-{get_python_version()}'
+    if hasattr(sys, "gettotalrefcount"):
+        pybuilddir += '-pydebug'
+    os.makedirs(pybuilddir, exist_ok=True)
+    destfile = os.path.join(pybuilddir, name + '.py')
+
+    with open(destfile, 'w', encoding='utf8') as f:
+        f.write('# system configuration generated and used by'
+                ' the sysconfig module\n')
+        f.write('build_time_vars = ')
+        _print_config_dict(vars, stream=f)
+
+    # Create file used for sys.path fixup -- see Modules/getpath.c
+    with open('pybuilddir.txt', 'w', encoding='utf8') as f:
+        f.write(pybuilddir)
+
+
+def _print_dict(title, data):
+    for index, (key, value) in enumerate(sorted(data.items())):
+        if index == 0:
+            print(f'{title}: ')
+        print(f'\t{key} = "{value}"')
+
+
+def _main():
+    """Display all information sysconfig detains."""
+    if '--generate-posix-vars' in sys.argv:
+        _generate_posix_vars()
+        return
+    print(f'Platform: "{get_platform()}"')
+    print(f'Python version: "{get_python_version()}"')
+    print(f'Current installation scheme: "{get_default_scheme()}"')
+    print()
+    _print_dict('Paths', get_paths())
+    print()
+    _print_dict('Variables', get_config_vars())
+
+
+if __name__ == '__main__':
+    _main()
diff --git a/Lib/test/test_sysconfig.py b/Lib/test/test_sysconfig.py
index a077ac5..2a6813f 100644
--- a/Lib/test/test_sysconfig.py
+++ b/Lib/test/test_sysconfig.py
@@ -16,7 +16,8 @@ import sysconfig
 from sysconfig import (get_paths, get_platform, get_config_vars,
                        get_path, get_path_names, _INSTALL_SCHEMES,
                        get_default_scheme, get_scheme_names, get_config_var,
-                       _expand_vars, _get_preferred_schemes, _main)
+                       _expand_vars, _get_preferred_schemes)
+from sysconfig.__main__ import _main, _parse_makefile
 import _imp
 import _osx_support
 import _sysconfig
@@ -539,7 +540,7 @@ class MakefileTests(unittest.TestCase):
             print("var5=dollar$$5", file=makefile)
             print("var6=${var3}/lib/python3.5/config-$(VAR2)$(var5)"
                   "-x86_64-linux-gnu", file=makefile)
-        vars = sysconfig._parse_makefile(TESTFN)
+        vars = _parse_makefile(TESTFN)
         self.assertEqual(vars, {
             'var1': 'ab42',
             'VAR2': 'b42',