Mercurial > hg-stable
view Makefile @ 13704:a464763e99f1
dirstate: avoid a race with multiple commits in the same process
(issue2264, issue2516)
The race happens when two commits in a row change the same file
without changing its size, *if* those two commits happen in the same
second in the same process while holding the same repo lock. For
example:
commit 1:
M a
M b
commit 2: # same process, same second, same repo lock
M b # modify b without changing its size
M c
This first manifested in transplant, which is the most common way to
do multiple commits in the same process. But it can manifest in any
script or extension that does multiple commits under the same repo
lock. (Thus, the test script tests both transplant and a custom script.)
The problem was that dirstate.status() failed to notice the change to
b when localrepo is about to do the second commit, meaning that change
gets left in the working directory. In the context of transplant, that
means either a crash ("RuntimeError: nothing committed after
transplant") or a silently inaccurate transplant, depending on whether
any other files were modified by the second transplanted changeset.
The fix is to make status() work a little harder when we have
previously marked files as clean (state 'normal') in the same process.
Specifically, dirstate.normal() adds files to self._lastnormal, and
other state-changing methods remove them. Then dirstate.status() puts
any files in self._lastnormal into state 'lookup', which will make
localrepository.status() read file contents to see if it has really
changed. So we pay a small performance penalty for the second (and
subsequent) commits in the same process, without affecting the common
case. Anything that does lots of status updates and checks in the
same process could suffer a performance hit.
Incidentally, there is a simpler fix: call dirstate.normallookup() on
every file updated by commit() at the end of the commit. The trouble
with that solution is that it imposes a performance penalty on the
common case: it means the next status-dependent hg command after every
"hg commit" will be a little bit slower. The patch here is more
complex, but only affects performance for the uncommon case.
author | Greg Ward <greg@gerg.ca> |
---|---|
date | Sun, 20 Mar 2011 17:41:09 -0400 |
parents | 37d0fe7a14da |
children | 1a919c3271bf |
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# 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 PREFIX=/usr/local export PREFIX PYTHON=python PURE= PYFILES:=$(shell find mercurial hgext doc -name '*.py') DOCFILES=mercurial/help/*.txt help: @echo 'Commonly used make targets:' @echo ' all - build program and documentation' @echo ' install - install program and man pages to PREFIX ($(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)' @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 -i build_mo $(PYTHON) hg version build: $(PYTHON) setup.py $(PURE) build doc: $(MAKE) -C doc clean: -$(PYTHON) setup.py clean --all # ignore errors from this command find . \( -name '*.py[cdo]' -o -name '*.so' \) -exec rm -f '{}' ';' rm -f MANIFEST tests/*.err rm -rf build mercurial/locale $(MAKE) -C doc clean 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)" --force install-home-doc: doc cd doc && $(MAKE) $(MFLAGS) PREFIX="$(HOME)" install MANIFEST-doc: $(MAKE) -C doc MANIFEST MANIFEST: MANIFEST-doc hg manifest > MANIFEST echo mercurial/__version__.py >> MANIFEST cat doc/MANIFEST >> MANIFEST dist: tests dist-notests dist-notests: doc MANIFEST TAR_OPTIONS="--owner=root --group=root --mode=u+w,go-w,a+rX-s" $(PYTHON) setup.py -q sdist tests: cd tests && $(PYTHON) run-tests.py $(TESTFLAGS) test-%: cd tests && $(PYTHON) run-tests.py $(TESTFLAGS) $@ update-pot: i18n/hg.pot i18n/hg.pot: $(PYFILES) $(DOCFILES) $(PYTHON) i18n/hggettext mercurial/commands.py \ hgext/*.py hgext/*/__init__.py mercurial/revset.py \ $(DOCFILES) > i18n/hg.pot # 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. echo $(PYFILES) | xargs \ xgettext --package-name "Mercurial" \ --msgid-bugs-address "<mercurial-devel@selenic.com>" \ --copyright-holder "Matt Mackall <mpm@selenic.com> and others" \ --from-code ISO-8859-1 --join --sort-by-file --add-comments=i18n: \ -d hg -p i18n -o hg.pot $(PYTHON) i18n/posplit i18n/hg.pot %.po: i18n/hg.pot msgmerge --no-location --update $@ $^ .PHONY: help all local build doc clean install install-bin install-doc \ install-home install-home-bin install-home-doc dist dist-notests tests \ update-pot