Move to src-layout.

The intention of this is better isolation. `trio` is no longer
accidentally on the (python) path and as such requires an explicit
installation for usage, this helps uncover issues in packaging data etc
early on (see
https://packaging.python.org/en/latest/discussions/src-layout-vs-flat-layout/).

This serves as the basis for switching to another build system as well; refs python-trio#2790.

.coveragerc

@@ -14,6 +14,11 @@ omit=
 # this doesn't corrupt the coverage files
 parallel=True
 
+[paths]
+source =
+  src/trio
+  **/site-packages/trio
+
 [report]
 precision = 1
 skip_covered = True

check.sh

@@ -11,7 +11,7 @@ fi
 
 # Test if the generated code is still up to date
 echo "::group::Generate Exports"
-python ./trio/_tools/gen_exports.py --test \
+python src/trio/_tools/gen_exports.py --test \
     || EXIT_STATUS=$?
 echo "::endgroup::"
 
@@ -21,21 +21,21 @@ echo "::endgroup::"
 # autoflake --recursive --in-place .
 # pyupgrade --py3-plus $(find . -name "*.py")
 echo "::group::Black"
-if ! black --check setup.py trio; then
+if ! black --check setup.py src/trio; then
     echo "* Black found issues" >> $GITHUB_STEP_SUMMARY
     EXIT_STATUS=1
-    black --diff setup.py trio
+    black --diff setup.py src/trio
     echo "::endgroup::"
     echo "::error:: Black found issues"
 else
     echo "::endgroup::"
 fi
 
 echo "::group::ISort"
-if ! isort --check setup.py trio; then
+if ! isort --check setup.py src/trio; then
     echo "* isort found issues." >> $GITHUB_STEP_SUMMARY
     EXIT_STATUS=1
-    isort --diff setup.py trio
+    isort --diff setup.py src/trio
     echo "::endgroup::"
     echo "::error:: isort found issues"
 else
@@ -44,7 +44,7 @@ fi
 
 # Run flake8, configured in pyproject.toml
 echo "::group::Flake8"
-flake8 trio/ || EXIT_STATUS=$?
+flake8 src/trio/ || EXIT_STATUS=$?
 echo "::endgroup::"
 
 # Run mypy on all supported platforms
@@ -55,16 +55,16 @@ echo "::group::Mypy"
 rm -f mypy_annotate.dat
 # Pipefail makes these pipelines fail if mypy does, even if mypy_annotate.py succeeds.
 set -o pipefail
-mypy trio --show-error-end --platform linux | python ./trio/_tools/mypy_annotate.py --dumpfile mypy_annotate.dat --platform Linux \
+mypy src/trio --show-error-end --platform linux | python ./src/trio/_tools/mypy_annotate.py --dumpfile mypy_annotate.dat --platform Linux \
     || { echo "* Mypy (Linux) found type errors." >> $GITHUB_STEP_SUMMARY; MYPY=1; }
 # Darwin tests FreeBSD too
-mypy trio --show-error-end --platform darwin | python ./trio/_tools/mypy_annotate.py --dumpfile mypy_annotate.dat --platform Mac \
+mypy src/trio --show-error-end --platform darwin | python ./src/trio/_tools/mypy_annotate.py --dumpfile mypy_annotate.dat --platform Mac \
     || { echo "* Mypy (Mac) found type errors." >> $GITHUB_STEP_SUMMARY; MYPY=1; }
-mypy trio --show-error-end --platform win32 | python ./trio/_tools/mypy_annotate.py --dumpfile mypy_annotate.dat --platform Windows \
+mypy src/trio --show-error-end --platform win32 | python ./src/trio/_tools/mypy_annotate.py --dumpfile mypy_annotate.dat --platform Windows \
     || { echo "* Mypy (Windows) found type errors." >> $GITHUB_STEP_SUMMARY; MYPY=1; }
 set +o pipefail
 # Re-display errors using Github's syntax, read out of mypy_annotate.dat
-python ./trio/_tools/mypy_annotate.py --dumpfile mypy_annotate.dat
+python ./src/trio/_tools/mypy_annotate.py --dumpfile mypy_annotate.dat
 # Then discard.
 rm -f mypy_annotate.dat
 echo "::endgroup::"
@@ -94,11 +94,11 @@ fi
 
 codespell || EXIT_STATUS=$?
 
-python trio/_tests/check_type_completeness.py --overwrite-file || EXIT_STATUS=$?
-if git status --porcelain trio/_tests/verify_types*.json | grep -q "M"; then
+python src/trio/_tests/check_type_completeness.py --overwrite-file || EXIT_STATUS=$?
+if git status --porcelain src/trio/_tests/verify_types*.json | grep -q "M"; then
     echo "* Type completeness changed, please update!" >> $GITHUB_STEP_SUMMARY
     echo "::error::Type completeness changed, please update!"
-    git --no-pager diff --color trio/_tests/verify_types*.json
+    git --no-pager diff --color src/trio/_tests/verify_types*.json
     EXIT_STATUS=1
 fi
 
@@ -112,8 +112,8 @@ Problems were found by static analysis (listed above).
 To fix formatting and see remaining errors, run
 
     pip install -r test-requirements.txt
-    black setup.py trio
-    isort setup.py trio
+    black setup.py src/trio
+    isort setup.py src/trio
     ./check.sh
 
 in your local checkout.

ci.sh

@@ -87,7 +87,7 @@ else
         # when installing, and then running 'certmgr.msc' and exporting the
         # certificate. See:
         #    http://www.migee.com/2010/09/24/solution-for-unattendedsilent-installs-and-would-you-like-to-install-this-device-software/
-        certutil -addstore "TrustedPublisher" trio/_tests/astrill-codesigning-cert.cer
+        certutil -addstore "TrustedPublisher" src/trio/_tests/astrill-codesigning-cert.cer
         # Double-slashes are how you tell windows-bash that you want a single
         # slash, and don't treat this as a unix-style filename that needs to
         # be replaced by a windows-style filename.

docs/source/conf.py

@@ -22,7 +22,7 @@
 # For our local_customization module
 sys.path.insert(0, os.path.abspath("."))
 # For trio itself
-sys.path.insert(0, os.path.abspath("../.."))
+sys.path.insert(0, os.path.abspath("../../src"))
 
 # https://docs.readthedocs.io/en/stable/builds.html#build-environment
 if "READTHEDOCS" in os.environ:

pyproject.toml

@@ -13,13 +13,13 @@ ignore-words-list = 'astroid,crasher,asend'
 [tool.flake8]
 extend-ignore = ['D', 'E', 'W', 'F403', 'F405', 'F821', 'F822']
 per-file-ignores = [
-  'trio/__init__.py: F401',
-  'trio/_core/__init__.py: F401',
-  'trio/_core/_tests/test_multierror_scripts/*: F401',
-  'trio/abc.py: F401',
-  'trio/lowlevel.py: F401',
-  'trio/socket.py: F401',
-  'trio/testing/__init__.py: F401'
+  'src/trio/__init__.py: F401',
+  'src/trio/_core/__init__.py: F401',
+  'src/trio/_core/_tests/test_multierror_scripts/*: F401',
+  'src/trio/abc.py: F401',
+  'src/trio/lowlevel.py: F401',
+  'src/trio/socket.py: F401',
+  'src/trio/testing/__init__.py: F401'
 ]
 
 [tool.isort]
@@ -61,48 +61,48 @@ disallow_untyped_calls = false
 [[tool.mypy.overrides]]
 module = [
 # 2761
-"trio/_core/_generated_io_windows",
-"trio/_core/_io_windows",
+"src/trio/_core/_generated_io_windows",
+"src/trio/_core/_io_windows",
 
 # internal
-"trio/_windows_pipes",
+"src/trio/_windows_pipes",
 
 # tests
-"trio/testing/_fake_net",
-"trio/_core/_tests/test_guest_mode",
-"trio/_core/_tests/test_instrumentation",
-"trio/_core/_tests/test_ki",
-"trio/_core/_tests/test_local",
-"trio/_core/_tests/test_mock_clock",
-"trio/_core/_tests/test_multierror",
-"trio/_core/_tests/test_multierror_scripts/ipython_custom_exc",
-"trio/_core/_tests/test_multierror_scripts/simple_excepthook",
-"trio/_core/_tests/test_parking_lot",
-"trio/_core/_tests/test_thread_cache",
-"trio/_core/_tests/test_unbounded_queue",
-"trio/_tests/test_exports",
-"trio/_tests/test_file_io",
-"trio/_tests/test_highlevel_generic",
-"trio/_tests/test_highlevel_open_tcp_listeners",
-"trio/_tests/test_highlevel_open_tcp_stream",
-"trio/_tests/test_highlevel_open_unix_stream",
-"trio/_tests/test_highlevel_serve_listeners",
-"trio/_tests/test_highlevel_socket",
-"trio/_tests/test_highlevel_ssl_helpers",
-"trio/_tests/test_path",
-"trio/_tests/test_scheduler_determinism",
-"trio/_tests/test_socket",
-"trio/_tests/test_ssl",
-"trio/_tests/test_subprocess",
-"trio/_tests/test_sync",
-"trio/_tests/test_testing",
-"trio/_tests/test_threads",
-"trio/_tests/test_timeouts",
-"trio/_tests/test_tracing",
-"trio/_tests/test_util",
-"trio/_tests/test_wait_for_object",
-"trio/_tests/test_windows_pipes",
-"trio/_tests/tools/test_gen_exports",
+"src/trio/testing/_fake_net",
+"src/trio/_core/_tests/test_guest_mode",
+"src/trio/_core/_tests/test_instrumentation",
+"src/trio/_core/_tests/test_ki",
+"src/trio/_core/_tests/test_local",
+"src/trio/_core/_tests/test_mock_clock",
+"src/trio/_core/_tests/test_multierror",
+"src/trio/_core/_tests/test_multierror_scripts/ipython_custom_exc",
+"src/trio/_core/_tests/test_multierror_scripts/simple_excepthook",
+"src/trio/_core/_tests/test_parking_lot",
+"src/trio/_core/_tests/test_thread_cache",
+"src/trio/_core/_tests/test_unbounded_queue",
+"src/trio/_tests/test_exports",
+"src/trio/_tests/test_file_io",
+"src/trio/_tests/test_highlevel_generic",
+"src/trio/_tests/test_highlevel_open_tcp_listeners",
+"src/trio/_tests/test_highlevel_open_tcp_stream",
+"src/trio/_tests/test_highlevel_open_unix_stream",
+"src/trio/_tests/test_highlevel_serve_listeners",
+"src/trio/_tests/test_highlevel_socket",
+"src/trio/_tests/test_highlevel_ssl_helpers",
+"src/trio/_tests/test_path",
+"src/trio/_tests/test_scheduler_determinism",
+"src/trio/_tests/test_socket",
+"src/trio/_tests/test_ssl",
+"src/trio/_tests/test_subprocess",
+"src/trio/_tests/test_sync",
+"src/trio/_tests/test_testing",
+"src/trio/_tests/test_threads",
+"src/trio/_tests/test_timeouts",
+"src/trio/_tests/test_tracing",
+"src/trio/_tests/test_util",
+"src/trio/_tests/test_wait_for_object",
+"src/trio/_tests/test_windows_pipes",
+"src/trio/_tests/tools/test_gen_exports",
 ]
 check_untyped_defs = false
 disallow_any_decorated = false
@@ -142,6 +142,7 @@ issue_format = "`#{issue} <https://github.com/python-trio/trio/issues/{issue}>`_
 # - At release time after bumping version number, run: towncrier
 # (or towncrier --draft)
 package = "trio"
+package_dir = "src"
 underlines = ["-", "~", "^"]
 
 [[tool.towncrier.type]]

setup.py

@@ -1,6 +1,6 @@
 from setuptools import find_packages, setup
 
-exec(open("trio/_version.py", encoding="utf-8").read())
+exec(open("src/trio/_version.py", encoding="utf-8").read())
 
 LONG_DESC = """\
 .. image:: https://raw.githubusercontent.com/python-trio/trio/9b0bec646a31e0d0f67b8b6ecc6939726faf3e17/logo/logo-with-background.svg
@@ -80,7 +80,8 @@
     author_email="[email protected]",
     url="https://github.com/python-trio/trio",
     license="MIT OR Apache-2.0",
-    packages=find_packages(),
+    packages=find_packages(where="src"),
+    package_dir={"": "src"},
     install_requires=[
         # attrs 19.2.0 adds `eq` option to decorators
         # attrs 20.1.0 adds @frozen