Let user passes in the prepared directory manually

Author: uranusjr

src/build/__init__.py

@@ -165,7 +165,6 @@ def __init__(self, srcdir, config_settings=None, python_executable=sys.executabl
             backend_path=self._build_system.get('backend-path'),
             python_executable=python_executable,
         )
-        self._prepared_metadata_directories = {}  # type: Dict[str, str]
 
     @property
     def python_executable(self):  # type: () -> Union[bytes, Text]
@@ -239,7 +238,7 @@ def prepare(self, distribution, outdir):  # type: (str, str) -> Optional[str]
         try:
             with _working_directory(self.srcdir):
                 basename = prepare(outdir, self.config_settings, _allow_fallback=False)  # type: str
-            self._prepared_metadata_directories[distribution] = path = os.path.join(outdir, basename)
+            path = os.path.join(outdir, basename)
         except pep517.wrappers.BackendUnavailable:
             raise BuildException("Backend '{}' is not available.".format(self._backend))
         except pep517.wrappers.HookMissing:
@@ -248,7 +247,7 @@ def prepare(self, distribution, outdir):  # type: (str, str) -> Optional[str]
             raise BuildBackendException('Backend operation failed: {!r}'.format(e))
         return path
 
-    def build(self, distribution, outdir):  # type: (str, str) -> str
+    def build(self, distribution, outdir, metadata=None):  # type: (str, str, Optional[str]) -> str
         """
         Build a distribution.
 
@@ -265,12 +264,9 @@ def build(self, distribution, outdir):  # type: (str, str) -> str
         else:
             os.mkdir(outdir)
 
-        try:
-            metadata_directory = self._prepared_metadata_directories.pop(distribution)
-        except KeyError:
-            kwargs = {}  # type: Dict[str, str]
-        else:
-            kwargs = {'metadata_directory': metadata_directory}
+        kwargs = {}
+        if metadata is not None:
+            kwargs['metadata_directory'] = metadata
 
         try:
             with _working_directory(self.srcdir):