Make it possible for build_py to export the output mapping

1 files changed, 41 insertions, 8 deletions

diff --git a/setuptools/command/build_py.py b/setuptools/command/build_py.py
index dab81327..3163752f 100644
--- a/setuptools/command/build_py.py
+++ b/setuptools/command/build_py.py
@@ -11,6 +11,8 @@ import itertools
 import stat
 import warnings
 from pathlib import Path
+from typing import Dict, Iterator, List, Optional, Tuple
+
 from setuptools._deprecation_warning import SetuptoolsDeprecationWarning
 from setuptools.extern.more_itertools import unique_everseen
 
@@ -28,8 +30,13 @@ class build_py(orig.build_py):
     Also, this version of the 'build_py' command allows you to specify both
     'py_modules' and 'packages' in the same setup operation.
     """
+    editable_mode: bool = False
+    existing_egg_info_dir: Optional[str] = None  #: Private API, internal use only.
 
-    existing_egg_info_dir = None  #: Private API, setuptools internal use only.
+    def initialize_options(self):
+        super().initialize_options()
+        self.editable_mode = False
+        self.existing_egg_info_dir = None
 
     def finalize_options(self):
         orig.build_py.finalize_options(self)
@@ -52,7 +59,8 @@ class build_py(orig.build_py):
 
     def run(self):
         """Build modules, packages, and copy data files to build directory"""
-        if not self.py_modules and not self.packages:
+        # if self.editable_mode or not (self.py_modules and self.packages):
+        if not (self.py_modules or self.packages) or self.editable_mode:
             return
 
         if self.py_modules:
@@ -125,16 +133,41 @@ class build_py(orig.build_py):
         )
         return self.exclude_data_files(package, src_dir, files)
 
-    def build_package_data(self):
-        """Copy data files into build directory"""
+    def get_outputs(self, include_bytecode=1) -> List[str]:
+        """See :class:`setuptools.commands.build.SubCommand`"""
+        if self.editable_mode:
+            return list(self.get_output_mapping().keys())
+        return super().get_outputs(include_bytecode)
+
+    def get_output_mapping(self) -> Dict[str, str]:
+        """See :class:`setuptools.commands.build.SubCommand`"""
+        mapping = itertools.chain(
+            self._get_package_data_output_mapping(),
+            self._get_module_mapping(),
+        )
+        return dict(sorted(mapping, key=lambda x: x[0]))
+
+    def _get_module_mapping(self) -> Iterator[Tuple[str, str]]:
+        """Iterate over all modules producing (dest, src) pairs."""
+        for (package, module, module_file) in self.find_all_modules():
+            package = package.split('.')
+            filename = self.get_module_outfile(self.build_lib, package, module)
+            yield (filename, module_file)
+
+    def _get_package_data_output_mapping(self) -> Iterator[Tuple[str, str]]:
+        """Iterate over package data producing (dest, src) pairs."""
         for package, src_dir, build_dir, filenames in self.data_files:
             for filename in filenames:
                 target = os.path.join(build_dir, filename)
-                self.mkpath(os.path.dirname(target))
                 srcfile = os.path.join(src_dir, filename)
-                outf, copied = self.copy_file(srcfile, target)
-                make_writable(target)
-                srcfile = os.path.abspath(srcfile)
+                yield (target, srcfile)
+
+    def build_package_data(self):
+        """Copy data files into build directory"""
+        for target, srcfile in self._get_package_data_output_mapping():
+            self.mkpath(os.path.dirname(target))
+            _outf, _copied = self.copy_file(srcfile, target)
+            make_writable(target)
 
     def analyze_manifest(self):
         self.manifest_files = mf = {}