Add PEP 660 support (editables)

Author: sbidoul

doc/callhooks.rst

@@ -12,12 +12,18 @@ Calling the build system
 
    .. automethod:: get_requires_for_build_wheel
 
+   .. automethod:: get_requires_for_build_editable
+
    .. automethod:: prepare_metadata_for_build_wheel
 
+   .. automethod:: prepare_metadata_for_build_editable
+
    .. automethod:: build_sdist
 
    .. automethod:: build_wheel
 
+   .. automethod:: build_editable
+
    .. automethod:: subprocess_runner
 
 Subprocess runners

pep517/in_process/_in_process.py

@@ -114,6 +114,20 @@ def get_requires_for_build_wheel(config_settings):
         return hook(config_settings)
 
 
+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)
+
+
 def prepare_metadata_for_build_wheel(
         metadata_directory, config_settings, _allow_fallback):
     """Invoke optional prepare_metadata_for_build_wheel
@@ -134,6 +148,27 @@ def prepare_metadata_for_build_wheel(
         return hook(metadata_directory, 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 an editable wheel 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()
+        whl_basename = backend.build_editable(metadata_directory, config_settings)
+        return _get_wheel_metadata_from_wheel(whl_basename, metadata_directory,
+                                              config_settings)
+    else:
+        return hook(metadata_directory, config_settings)
+
+
 WHEEL_BUILT_MARKER = 'PEP517_ALREADY_BUILT_WHEEL'
 
 
@@ -205,6 +240,27 @@ def build_wheel(wheel_directory, config_settings, metadata_directory=None):
                                         metadata_directory)
 
 
+def build_editable(wheel_directory, config_settings, metadata_directory=None):
+    """Invoke the optional build_editable hook.
+
+    If a wheel was already built in the
+    prepare_metadata_for_build_editable fallback, this
+    will copy it rather than rebuilding the wheel.
+    """
+    prebuilt_whl = _find_already_built_wheel(metadata_directory)
+    if prebuilt_whl:
+        shutil.copy2(prebuilt_whl, wheel_directory)
+        return os.path.basename(prebuilt_whl)
+
+    backend = _build_backend()
+    try:
+        hook = backend.build_editable
+    except AttributeError:
+        raise HookMissing()
+    else:
+        return hook(wheel_directory, config_settings, metadata_directory)
+
+
 def get_requires_for_build_sdist(config_settings):
     """Invoke the optional get_requires_for_build_wheel hook
 

pep517/wrappers.py

@@ -207,6 +207,59 @@ def build_wheel(
             'metadata_directory': metadata_directory,
         })
 
+    def get_requires_for_build_editblae(self, config_settings=None):
+        """Identify packages required for building an editable wheel
+
+        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_editblae', {
+            '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 an editable
+        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 an editable 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 get_requires_for_build_sdist(self, config_settings=None):
         """Identify packages required for building a wheel