Vendor tomli 1.2.3 in flit_core

.coveragerc

@@ -1,2 +1,3 @@
 [run]
 omit = */tests/*
+    */flit_core/vendor/*

bootstrap_dev.py

@@ -14,8 +14,6 @@
 os.chdir(str(my_dir))
 sys.path.insert(0, 'flit_core')
 
-from flit_core import build_thyself
-from flit_core.config import LoadedConfig
 from flit.install import Installer
 
 ap = argparse.ArgumentParser()
@@ -24,20 +22,14 @@
 
 logging.basicConfig(level=logging.INFO)
 
-# Construct config for flit_core
-core_config = LoadedConfig()
-core_config.module = 'flit_core'
-core_config.metadata = build_thyself.metadata_dict
-core_config.reqs_by_extra['.none'] = build_thyself.metadata.requires_dist
-
 install_kwargs = {'symlink': True}
 if os.name == 'nt':
     # Use .pth files instead of symlinking on Windows
     install_kwargs = {'symlink': False, 'pth': True}
 
 # Install flit_core
-Installer(
-    my_dir / 'flit_core', core_config, user=args.user, **install_kwargs
+Installer.from_ini_path(
+    my_dir / 'flit_core' / 'pyproject.toml', user=args.user, **install_kwargs
 ).install()
 print("Linked flit_core into site-packages.")
 

doc/bootstrap.rst

@@ -15,8 +15,8 @@ The key piece is ``flit_core``. This is a package which can build itself using
 nothing except Python and the standard library. From an unpacked source archive,
 you can run ``python build_dists.py``, of which the crucial part is::
 
-    from flit_core import build_thyself
-    whl_fname = build_thyself.build_wheel('dist/')
+    from flit_core import buildapi
+    whl_fname = buildapi.build_wheel('dist/')
     print(os.path.join('dist', whl_fname))
 
 This produces a ``.whl`` wheel file, which you can unzip into your
@@ -25,11 +25,9 @@ building other packages. (You could also just copy ``flit_core`` from the
 source directory, but without the ``.dist-info`` folder, tools like pip won't
 know that it's installed.)
 
-Note that although ``flit_core`` has no *build* dependencies, it has one runtime
-dependency, `Tomli <https://pypi.org/project/tomli/>`_. Tomli is itself packaged
-with Flit, so after building ``flit_core``, you will need to use that to build
-Tomli, arranging for ``tomli`` to be importable directly from the source location
-(e.g. using the ``PYTHONPATH`` environment variable).
+As of version 3.6, flit_core bundles the ``tomli`` TOML parser, to avoid a
+dependency cycle. If you need to unbundle it, you will need to special-case
+installing flit_core and/or tomli to get around that cycle.
 
 I recommend that you get the `build <https://pypi.org/project/build/>`_ and
 `installer <https://pypi.org/project/installer/>`_ packages (and their

flit_core/build_dists.py

@@ -4,14 +4,14 @@
 """
 import os
 
-from flit_core import build_thyself
+from flit_core import buildapi
 
 os.chdir(os.path.dirname(os.path.abspath(__file__)))
 
 print("Building sdist")
-sdist_fname = build_thyself.build_sdist('dist/')
+sdist_fname = buildapi.build_sdist('dist/')
 print(os.path.join('dist', sdist_fname))
 
 print("\nBuilding wheel")
-whl_fname = build_thyself.build_wheel('dist/')
+whl_fname = buildapi.build_wheel('dist/')
 print(os.path.join('dist', whl_fname))

flit_core/flit_core/config.py

@@ -5,9 +5,9 @@
 import os
 import os.path as osp
 from pathlib import Path
-import tomli
 import re
 
+from .vendor import tomli
 from .versionno import normalise_version
 
 log = logging.getLogger(__name__)

flit_core/flit_core/tests/test_build_thyself.py

@@ -1,15 +1,16 @@
+"""Tests of flit_core building itself"""
 import os
 import os.path as osp
 import pytest
 import tarfile
 from testpath import assert_isdir, assert_isfile
 import zipfile
 
-from flit_core import build_thyself
+from flit_core import buildapi
 
 @pytest.fixture()
 def cwd_project():
-    proj_dir = osp.dirname(osp.dirname(osp.abspath(build_thyself.__file__)))
+    proj_dir = osp.dirname(osp.dirname(osp.abspath(buildapi.__file__)))
     if not osp.isfile(osp.join(proj_dir, 'pyproject.toml')):
         pytest.skip("need flit_core source directory")
 
@@ -21,9 +22,9 @@ def cwd_project():
         os.chdir(old_cwd)
 
 
-def test_prepare_metadata(tmp_path):
+def test_prepare_metadata(tmp_path, cwd_project):
     tmp_path = str(tmp_path)
-    dist_info = build_thyself.prepare_metadata_for_build_wheel(tmp_path)
+    dist_info = buildapi.prepare_metadata_for_build_wheel(tmp_path)
 
     assert dist_info.endswith('.dist-info')
     assert dist_info.startswith('flit_core')
@@ -36,7 +37,7 @@ def test_prepare_metadata(tmp_path):
 
 def test_wheel(tmp_path, cwd_project):
     tmp_path = str(tmp_path)
-    filename = build_thyself.build_wheel(tmp_path)
+    filename = buildapi.build_wheel(tmp_path)
 
     assert filename.endswith('.whl')
     assert filename.startswith('flit_core')
@@ -47,7 +48,7 @@ def test_wheel(tmp_path, cwd_project):
 
 def test_sdist(tmp_path, cwd_project):
     tmp_path = str(tmp_path)
-    filename = build_thyself.build_sdist(tmp_path)
+    filename = buildapi.build_sdist(tmp_path)
 
     assert filename.endswith('.tar.gz')
     assert filename.startswith('flit_core')

flit_core/flit_core/vendor/README

@@ -0,0 +1,13 @@
+flit_core bundles the 'tomli' TOML parser, to avoid a bootstrapping problem.
+tomli is packaged using Flit, so there would be a dependency cycle when building
+from source. Vendoring a copy of tomli avoids this. The code in tomli is under
+the MIT license, and the LICENSE file is in the .dist-info folder.
+
+If you want to unbundle tomli and rely on it as a separate package, you can
+replace the package with Python code doing 'from tomli import *'. You will
+probably need to work around the dependency cycle between flit_core and tomli.
+
+Bundling a TOML parser should be a special case - I don't plan on bundling
+anything else in flit_core (or depending on any other packages).
+I hope that a TOML parser will be added to the Python standard library, and then
+this bundled parser will go away.

flit_core/flit_core/vendor/tomli-1.2.3.dist-info/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Taneli Hukkinen
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.