support PEP 660 hook calling

pep517/in_process/_in_process.py

@@ -149,14 +149,19 @@ def _dist_info_files(whl_zip):
 
 
 def _get_wheel_metadata_from_wheel(
-        backend, metadata_directory, config_settings):
+        backend, metadata_directory, config_settings, editable=False):
     """Build a wheel and extract the metadata from it.
 
     Fallback for when the build backend does not
-    define the 'get_wheel_metadata' hook.
+    define the 'prepare_metadata' hook.
     """
     from zipfile import ZipFile
-    whl_basename = backend.build_wheel(metadata_directory, config_settings)
+    if editable:
+        whl_basename = backend.build_editable(
+            metadata_directory, config_settings)
+    else:
+        whl_basename = backend.build_wheel(
+            metadata_directory, config_settings)
     with open(os.path.join(metadata_directory, WHEEL_BUILT_MARKER), 'wb'):
         pass  # Touch marker file
 
@@ -167,7 +172,7 @@ def _get_wheel_metadata_from_wheel(
     return dist_info[0].split('/')[0]
 
 
-def _find_already_built_wheel(metadata_directory):
+def _find_already_built_wheel(metadata_directory, editable=False):
     """Check for a wheel already built during the get_wheel_metadata hook.
     """
     if not metadata_directory:
@@ -181,8 +186,9 @@ def _find_already_built_wheel(metadata_directory):
         print('Found wheel built marker, but no .whl files')
         return None
     if len(whl_files) > 1:
+        hook_name = 'build_editable' if editable else 'build_wheel'
         print('Found multiple .whl files; unspecified behaviour. '
-              'Will call build_wheel.')
+              'Will call {}.'.format(hook_name))
         return None
 
     # Exactly one .whl file
@@ -206,7 +212,7 @@ def build_wheel(wheel_directory, config_settings, metadata_directory=None):
 
 
 def get_requires_for_build_sdist(config_settings):
-    """Invoke the optional get_requires_for_build_wheel hook
+    """Invoke the optional get_requires_for_build_sdist hook
 
     Returns [] if the hook is not defined.
     """
@@ -219,6 +225,57 @@ def get_requires_for_build_sdist(config_settings):
         return hook(config_settings)
 
 
+def prepare_metadata_for_build_editable(
+        metadata_directory, config_settings, _allow_fallback):
+    """Invoke optional prepare_metadata_for_build_editable
+
+    Implements a fallback by building a wheel for editable if the hook
+    isn't defined, unless _allow_fallback is False in which case
+    HookMissing is raised.
+    """
+    backend = _build_backend()
+    try:
+        hook = backend.prepare_metadata_for_build_editable
+    except AttributeError:
+        if not _allow_fallback:
+            raise HookMissing()
+        return _get_wheel_metadata_from_wheel(backend, metadata_directory,
+                                              config_settings, editable=True)
+    else:
+        return hook(metadata_directory, config_settings)
+
+
+def build_editable(wheel_directory, config_settings, metadata_directory=None):
+    """Invoke the optional build_editable hook.
+    """
+    prebuilt_whl = _find_already_built_wheel(metadata_directory, editable=True)
+    if prebuilt_whl:
+        shutil.copy2(prebuilt_whl, wheel_directory)
+        return os.path.basename(prebuilt_whl)
+
+    backend = _build_backend()
+    try:
+        hook = backend.build_wheel_for_editable
+    except AttributeError:
+        raise HookMissing()
+    else:
+        return hook(wheel_directory, config_settings, metadata_directory)
+
+
+def get_requires_for_build_editable(config_settings):
+    """Invoke the optional get_requires_for_build_editable hook
+
+    Returns [] if the hook is not defined.
+    """
+    backend = _build_backend()
+    try:
+        hook = backend.get_requires_for_build_editable
+    except AttributeError:
+        return []
+    else:
+        return hook(config_settings)
+
+
 class _DummyException(Exception):
     """Nothing should ever raise this exception"""
 
@@ -244,6 +301,9 @@ def build_sdist(sdist_directory, config_settings):
     'build_wheel',
     'get_requires_for_build_sdist',
     'build_sdist',
+    'get_requires_for_build_editable',
+    'prepare_metadata_for_build_editable',
+    'build_editable',
 }
 
 

pep517/wrappers.py

@@ -234,6 +234,59 @@ def build_sdist(self, sdist_directory, config_settings=None):
             'config_settings': config_settings,
         })
 
+    def get_requires_for_build_editable(self, config_settings=None):
+        """Identify packages required for building a editable
+
+        Returns a list of dependency specifications, e.g.::
+
+            ["wheel >= 0.25", "setuptools"]
+
+        This does not include requirements specified in pyproject.toml.
+        It returns the result of calling the equivalently named hook in a
+        subprocess.
+        """
+        return self._call_hook('get_requires_for_build_editable', {
+            'config_settings': config_settings
+        })
+
+    def prepare_metadata_for_build_editable(
+            self, metadata_directory, config_settings=None,
+            _allow_fallback=True):
+        """Prepare a ``*.dist-info`` folder with metadata for this project.
+
+        Returns the name of the newly created folder.
+
+        If the build backend defines a hook with this name, it will be called
+        in a subprocess. If not, the backend will be asked to build a wheel,
+        and the dist-info extracted from that (unless _allow_fallback is
+        False).
+        """
+        return self._call_hook('prepare_metadata_for_build_editable', {
+            'metadata_directory': abspath(metadata_directory),
+            'config_settings': config_settings,
+            '_allow_fallback': _allow_fallback,
+        })
+
+    def build_editable(
+            self, wheel_directory, config_settings=None,
+            metadata_directory=None):
+        """Build a wheel from this project.
+
+        Returns the name of the newly created file.
+
+        In general, this will call the 'build_editable' hook in the backend.
+        However, if that was previously called by
+        'prepare_metadata_for_build_editable', and the same metadata_directory is
+        used, the previously built wheel will be copied to wheel_directory.
+        """
+        if metadata_directory is not None:
+            metadata_directory = abspath(metadata_directory)
+        return self._call_hook('build_editable', {
+            'wheel_directory': abspath(wheel_directory),
+            'config_settings': config_settings,
+            'metadata_directory': metadata_directory,
+        })
+
     def _call_hook(self, hook_name, kwargs):
         # On Python 2, pytoml returns Unicode values (which is correct) but the
         # environment passed to check_call needs to contain string values. We