view Makefile @ 44118:f81c17ec303c

hgdemandimport: apply lazy module loading to sys.meta_path finders

Python's `sys.meta_path` finders are the primary objects whose job it
is to find a module at import time. When `import` is called, Python
iterates objects in this list and calls `o.find_spec(...)` to find
a `ModuleSpec` (or None if the module couldn't be found by that
finder). If no meta path finder can find a module, import fails.

One of the default meta path finders is `PathFinder`. Its job is to
import modules from the filesystem and is probably the most important
importer. This finder looks at `sys.path` and `sys.path_hooks` to do
its job.

The `ModuleSpec` returned by `MetaPathImporter.find_spec()` has a
`loader` attribute, which defines the concrete module loader to use.
`sys.path_hooks` is a hook point for teaching `PathFinder` to
instantiate custom loader types.

Previously, we injected a custom `sys.path_hook` that told `PathFinder`
to wrap the default loaders with a loader that creates a module object
that is lazy.

This approach worked. But its main limitation was that it only applied
to the `PathFinder` meta path importer. There are other meta path
importers that are registered. And in the case of PyOxidizer loading
modules from memory, `PathFinder` doesn't come into play since
PyOxidizer's own meta path importer was handling all imports.

This commit changes our approach to lazy module loading by proxying
all meta path importers. Specifically, we overload the `find_spec()`
method to swap in a wrapped loader on the `ModuleSpec` before it
is returned. The end result of this is all meta path importers should
be lazy.

As much as I would have loved to utilize .__class__ manipulation to
achieve this, some meta path importers are implemented in C/Rust
in such a way that they cannot be monkeypatched. This is why we
use __getattribute__ to define a proxy.

Also, this change could theoretically open us up to regressions in
meta path importers whose loader is creating module objects which
can't be monkeypatched. But I'm not aware of any of these in the
wild. So I think we'll be safe.

According to hyperfine, this change yields a decent startup time win of
5-6ms:

```
Benchmark #1: ~/.pyenv/versions/3.6.10/bin/python ./hg version
  Time (mean ± σ):      86.8 ms ±   0.5 ms    [User: 78.0 ms, System: 8.7 ms]
  Range (min … max):    86.0 ms …  89.1 ms    50 runs

  Time (mean ± σ):      81.1 ms ±   2.7 ms    [User: 74.5 ms, System: 6.5 ms]
  Range (min … max):    77.8 ms …  90.5 ms    50 runs

Benchmark #2: ~/.pyenv/versions/3.7.6/bin/python ./hg version
  Time (mean ± σ):      78.9 ms ±   0.6 ms    [User: 70.2 ms, System: 8.7 ms]
  Range (min … max):    78.1 ms …  81.2 ms    50 runs

  Time (mean ± σ):      73.4 ms ±   0.6 ms    [User: 65.3 ms, System: 8.0 ms]
  Range (min … max):    72.4 ms …  75.7 ms    50 runs

Benchmark #3: ~/.pyenv/versions/3.8.1/bin/python ./hg version
  Time (mean ± σ):      78.1 ms ±   0.6 ms    [User: 70.2 ms, System: 7.9 ms]
  Range (min … max):    77.4 ms …  80.9 ms    50 runs

  Time (mean ± σ):      72.1 ms ±   0.4 ms    [User: 64.4 ms, System: 7.6 ms]
  Range (min … max):    71.4 ms …  74.1 ms    50 runs
```

Differential Revision: https://phab.mercurial-scm.org/D7954

# If you want to change PREFIX, do not just edit it below. The changed
# value wont get passed on to recursive make calls. You should instead
# override the variable on the command like:
#
# % make PREFIX=/opt/ install

export PREFIX=/usr/local
PYTHON?=python
$(eval HGROOT := $(shell pwd))
HGPYTHONS ?= $(HGROOT)/build/pythons
PURE=
PYFILESCMD=find mercurial hgext doc -name '*.py'
PYFILES:=$(shell $(PYFILESCMD))
DOCFILES=mercurial/helptext/*.txt
export LANGUAGE=C
export LC_ALL=C
TESTFLAGS ?= $(shell echo $$HGTESTFLAGS)
OSXVERSIONFLAGS ?= $(shell echo $$OSXVERSIONFLAGS)
CARGO = cargo

# Set this to e.g. "mingw32" to use a non-default compiler.
COMPILER=

COMPILERFLAG_tmp_ =
COMPILERFLAG_tmp_${COMPILER} ?= -c $(COMPILER)
COMPILERFLAG=${COMPILERFLAG_tmp_${COMPILER}}

help:
	@echo 'Commonly used make targets:'
	@echo '  all          - build program and documentation'
	@echo '  install      - install program and man pages to $$PREFIX ($(PREFIX))'
	@echo '  install-home - install with setup.py install --home=$$HOME ($(HOME))'
	@echo '  local        - build for inplace usage'
	@echo '  tests        - run all tests in the automatic test suite'
	@echo '  test-foo     - run only specified tests (e.g. test-merge1.t)'
	@echo '  dist         - run all tests and create a source tarball in dist/'
	@echo '  clean        - remove files created by other targets'
	@echo '                 (except installed files or dist source tarball)'
	@echo '  update-pot   - update i18n/hg.pot'
	@echo
	@echo 'Example for a system-wide installation under /usr/local:'
	@echo '  make all && su -c "make install" && hg version'
	@echo
	@echo 'Example for a local installation (usable in this directory):'
	@echo '  make local && ./hg version'

all: build doc

local:
	$(PYTHON) setup.py $(PURE) \
	  build_py -c -d . \
	  build_ext $(COMPILERFLAG) -i \
	  build_hgexe $(COMPILERFLAG) -i \
	  build_mo
	env HGRCPATH= $(PYTHON) hg version

build:
	$(PYTHON) setup.py $(PURE) build $(COMPILERFLAG)

wheel:
	FORCE_SETUPTOOLS=1 $(PYTHON) setup.py $(PURE) bdist_wheel $(COMPILERFLAG)

doc:
	$(MAKE) -C doc

cleanbutpackages:
	-$(PYTHON) setup.py clean --all # ignore errors from this command
	find contrib doc hgext hgext3rd i18n mercurial tests hgdemandimport \
		\( -name '*.py[cdo]' -o -name '*.so' \) -exec rm -f '{}' ';'
	rm -f MANIFEST MANIFEST.in hgext/__index__.py tests/*.err
	rm -f mercurial/__modulepolicy__.py
	if test -d .hg; then rm -f mercurial/__version__.py; fi
	rm -rf build mercurial/locale
	$(MAKE) -C doc clean
	$(MAKE) -C contrib/chg distclean
	rm -rf rust/target
	rm -f mercurial/rustext.so

clean: cleanbutpackages
	rm -rf packages

install: install-bin install-doc

install-bin: build
	$(PYTHON) setup.py $(PURE) install --root="$(DESTDIR)/" --prefix="$(PREFIX)" --force

install-doc: doc
	cd doc && $(MAKE) $(MFLAGS) install

install-home: install-home-bin install-home-doc

install-home-bin: build
	$(PYTHON) setup.py $(PURE) install --home="$(HOME)" --prefix="" --force

install-home-doc: doc
	cd doc && $(MAKE) $(MFLAGS) PREFIX="$(HOME)" install

MANIFEST-doc:
	$(MAKE) -C doc MANIFEST

MANIFEST.in: MANIFEST-doc
	hg manifest | sed -e 's/^/include /' > MANIFEST.in
	echo include mercurial/__version__.py >> MANIFEST.in
	sed -e 's/^/include /' < doc/MANIFEST >> MANIFEST.in

dist:	tests dist-notests

dist-notests:	doc MANIFEST.in
	TAR_OPTIONS="--owner=root --group=root --mode=u+w,go-w,a+rX-s" $(PYTHON) setup.py -q sdist

check: tests

tests:
        # Run Rust tests if cargo is installed
	if command -v $(CARGO) >/dev/null 2>&1; then \
		$(MAKE) rust-tests; \
	fi
	cd tests && $(PYTHON) run-tests.py $(TESTFLAGS)

test-%:
	cd tests && $(PYTHON) run-tests.py $(TESTFLAGS) $@

testpy-%:
	@echo Looking for Python $* in $(HGPYTHONS)
	[ -e $(HGPYTHONS)/$*/bin/python ] || ( \
	cd $$(mktemp --directory --tmpdir) && \
        $(MAKE) -f $(HGROOT)/contrib/Makefile.python PYTHONVER=$* PREFIX=$(HGPYTHONS)/$* python )
	cd tests && $(HGPYTHONS)/$*/bin/python run-tests.py $(TESTFLAGS)

rust-tests: py_feature = $(shell $(PYTHON) -c \
 'import sys; print(["python27-bin", "python3-bin"][sys.version_info[0] >= 3])')
rust-tests:
	cd $(HGROOT)/rust/hg-cpython \
		&& $(CARGO) test --quiet --all \
			--no-default-features --features "$(py_feature)"

check-code:
	hg manifest | xargs python contrib/check-code.py

format-c:
	clang-format --style file -i \
	  `hg files 'set:(**.c or **.cc or **.h) and not "listfile:contrib/clang-format-ignorelist"'`

update-pot: i18n/hg.pot

i18n/hg.pot: $(PYFILES) $(DOCFILES) i18n/posplit i18n/hggettext
	$(PYTHON) i18n/hggettext mercurial/commands.py \
	  hgext/*.py hgext/*/__init__.py \
	  mercurial/fileset.py mercurial/revset.py \
	  mercurial/templatefilters.py \
	  mercurial/templatefuncs.py \
	  mercurial/templatekw.py \
	  mercurial/filemerge.py \
	  mercurial/hgweb/webcommands.py \
	  mercurial/util.py \
	  $(DOCFILES) > i18n/hg.pot.tmp
        # All strings marked for translation in Mercurial contain
        # ASCII characters only. But some files contain string
        # literals like this '\037\213'. xgettext thinks it has to
        # parse them even though they are not marked for translation.
        # Extracting with an explicit encoding of ISO-8859-1 will make
        # xgettext "parse" and ignore them.
	$(PYFILESCMD) | xargs \
	  xgettext --package-name "Mercurial" \
	  --msgid-bugs-address "<[e-mail]>" \
	  --copyright-holder "Matt Mackall <[e-mail]> and others" \
	  --from-code ISO-8859-1 --join --sort-by-file --add-comments=i18n: \
	  -d hg -p i18n -o hg.pot.tmp
	$(PYTHON) i18n/posplit i18n/hg.pot.tmp
        # The target file is not created before the last step. So it never is in
        # an intermediate state.
	mv -f i18n/hg.pot.tmp i18n/hg.pot

%.po: i18n/hg.pot
        # work on a temporary copy for never having a half completed target
	cp $@ $@.tmp
	msgmerge --no-location --update $@.tmp $^
	mv -f $@.tmp $@

# Packaging targets

packaging_targets := \
  centos5 \
  centos6 \
  centos7 \
  centos8 \
  deb \
  docker-centos5 \
  docker-centos6 \
  docker-centos7 \
  docker-centos8 \
  docker-debian-bullseye \
  docker-debian-buster \
  docker-debian-stretch \
  docker-fedora \
  docker-ubuntu-trusty \
  docker-ubuntu-trusty-ppa \
  docker-ubuntu-xenial \
  docker-ubuntu-xenial-ppa \
  docker-ubuntu-artful \
  docker-ubuntu-artful-ppa \
  docker-ubuntu-bionic \
  docker-ubuntu-bionic-ppa \
  fedora \
  linux-wheels \
  linux-wheels-x86_64 \
  linux-wheels-i686 \
  ppa

# Forward packaging targets for convenience.
$(packaging_targets):
	$(MAKE) -C contrib/packaging $@

osx:
	rm -rf build/mercurial
	/usr/bin/python2.7 setup.py install --optimize=1 \
	  --root=build/mercurial/ --prefix=/usr/local/ \
	  --install-lib=/Library/Python/2.7/site-packages/
	make -C doc all install DESTDIR="$(PWD)/build/mercurial/"
        # Place a bogon .DS_Store file in the target dir so we can be
        # sure it doesn't get included in the final package.
	touch build/mercurial/.DS_Store
        # install zsh completions - this location appears to be
        # searched by default as of macOS Sierra.
	install -d build/mercurial/usr/local/share/zsh/site-functions/
	install -m 0644 contrib/zsh_completion build/mercurial/usr/local/share/zsh/site-functions/_hg
        # install bash completions - there doesn't appear to be a
        # place that's searched by default for bash, so we'll follow
        # the lead of Apple's git install and just put it in a
        # location of our own.
	install -d build/mercurial/usr/local/hg/contrib/
	install -m 0644 contrib/bash_completion build/mercurial/usr/local/hg/contrib/hg-completion.bash
	make -C contrib/chg \
	  HGPATH=/usr/local/bin/hg \
	  PYTHON=/usr/bin/python2.7 \
	  HGEXTDIR=/Library/Python/2.7/site-packages/hgext \
	  DESTDIR=../../build/mercurial \
	  PREFIX=/usr/local \
	  clean install
	mkdir -p $${OUTPUTDIR:-dist}
	HGVER=$$(python contrib/genosxversion.py $(OSXVERSIONFLAGS) build/mercurial/Library/Python/2.7/site-packages/mercurial/__version__.py) && \
	OSXVER=$$(sw_vers -productVersion | cut -d. -f1,2) && \
	pkgbuild --filter \\.DS_Store --root build/mercurial/ \
	  --identifier org.mercurial-scm.mercurial \
	  --version "$${HGVER}" \
	  build/mercurial.pkg && \
	productbuild --distribution contrib/packaging/macosx/distribution.xml \
	  --package-path build/ \
	  --version "$${HGVER}" \
	  --resources contrib/packaging/macosx/ \
	  "$${OUTPUTDIR:-dist/}"/Mercurial-"$${HGVER}"-macosx"$${OSXVER}".pkg

.PHONY: help all local build doc cleanbutpackages clean install install-bin \
	install-doc install-home install-home-bin install-home-doc \
	dist dist-notests check tests rust-tests check-code format-c \
	update-pot \
	$(packaging_targets) \
	osx