push: rework the computation of fallbackheads to be correct
The previous computation tried to be smart but ended up being wrong. This was
caught by phase movement test while reworking the phase discovery logic to be
faster.
The previous logic was failing to catch case where the pushed set was not based
on a common heads (i.e. when the discovery seemed to have "over discovered"
content, outside the pushed set)
In the following graph, `e` is a common head and we `hg push -r f`. We need to
detect `c` as a fallback heads and we previous failed to do so::
e
|
d f
|/
c
|
b
|
a
The performance impact of the change seems minimal. On the most impacted
repository at hand (mozilla-try), the slowdown seems mostly mixed in the
overall noise `hg push` but seems to be in the hundred of milliseconds order of
magnitude. When using rust, we seems to be a bit faster, probably because we
leverage more accelaratd internals.
I added a couple of performance related common for further investigation later
on.
PYTHONVER=2.7.16
PYTHONNAME=python-
PREFIX=$(HOME)/bin/prefix-$(PYTHONNAME)$(PYTHONVER)
SYMLINKDIR=$(HOME)/bin
help:
@echo
@echo 'Make a custom installation of a Python version'
@echo
@echo 'Common make parameters:'
@echo ' PYTHONVER=... [$(PYTHONVER)]'
@echo ' PREFIX=... [$(PREFIX)]'
@echo ' SYMLINKDIR=... [$(SYMLINKDIR) creating $(PYTHONNAME)$(PYTHONVER)]'
@echo
@echo 'Common make targets:'
@echo ' python - install Python $$PYTHONVER in $$PREFIX'
@echo ' symlink - create a $$SYMLINKDIR/$(PYTHONNAME)$$PYTHONVER symlink'
@echo
@echo 'Example: create a temporary Python installation:'
@echo ' $$ make -f Makefile.python python PYTHONVER=${PYTHONVER} PREFIX=/tmp/p27'
@echo ' $$ /tmp/p27/bin/python -V'
@echo ' Python 2.7'
@echo
@echo 'Some external libraries are required for building Python: zlib bzip2 openssl.'
@echo 'Make sure their development packages are installed systemwide.'
# fedora: yum install zlib-devel bzip2-devel openssl-devel
# debian: apt-get install zlib1g-dev libbz2-dev libssl-dev
@echo
@echo 'To build a nice collection of interesting Python versions:'
@echo ' $$ for v in 2.{6{,.1,.2,.9},7{,.8,.10}}; do'
@echo ' make -f Makefile.python symlink PYTHONVER=$$v || break; done'
@echo 'To run a Mercurial test on all these Python versions:'
@echo ' $$ for py in `cd ~/bin && ls $(PYTHONNAME)2.*`; do'
@echo ' echo $$py; $$py run-tests.py test-http.t; echo; done'
@echo
export LANGUAGE=C
export LC_ALL=C
python: $(PREFIX)/bin/python docutils
printf 'import sys, zlib, bz2, docutils, ssl' | $(PREFIX)/bin/python
PYTHON_SRCDIR=Python-$(PYTHONVER)
PYTHON_SRCFILE=$(PYTHON_SRCDIR).tgz
$(PREFIX)/bin/python:
[ -f $(PYTHON_SRCFILE) ] || wget http://www.python.org/ftp/python/$(PYTHONVER)/$(PYTHON_SRCFILE) || curl -OL http://www.python.org/ftp/python/$(PYTHONVER)/$(PYTHON_SRCFILE) || [ -f $(PYTHON_SRCFILE) ]
rm -rf $(PYTHON_SRCDIR)
tar xf $(PYTHON_SRCFILE)
# Debian/Ubuntu disables SSLv2,3 the hard way, disable it on old Pythons too
-sed -i 's,self.*SSLv[23]_method(),0;//\0,g' $(PYTHON_SRCDIR)/Modules/_ssl.c
# Find multiarch system libraries on Ubuntu and disable fortify error when setting argv
LDFLAGS="-L/usr/lib/`dpkg-architecture -qDEB_HOST_MULTIARCH`"; \
BASECFLAGS=-U_FORTIFY_SOURCE; \
export LDFLAGS BASECFLAGS; \
cd $(PYTHON_SRCDIR) && ./configure --prefix=$(PREFIX) && make all SVNVERSION=pwd && make install
printf 'import sys, zlib, bz2, ssl' | $(PREFIX)/bin/python
rm -rf $(PYTHON_SRCDIR)
DOCUTILSVER=0.12
DOCUTILS_SRCDIR=docutils-$(DOCUTILSVER)
DOCUTILS_SRCFILE=$(DOCUTILS_SRCDIR).tar.gz
docutils: $(PREFIX)/bin/python
@$(PREFIX)/bin/python -c 'import docutils' || ( set -ex; \
[ -f $(DOCUTILS_SRCFILE) ] || wget http://downloads.sourceforge.net/project/docutils/docutils/$(DOCUTILSVER)/$(DOCUTILS_SRCFILE) || [ -f $(DOCUTILS_SRCFILE) ]; \
rm -rf $(DOCUTILS_SRCDIR); \
tar xf $(DOCUTILS_SRCFILE); \
cd $(DOCUTILS_SRCDIR) && $(PREFIX)/bin/python setup.py install --prefix=$(PREFIX); \
$(PREFIX)/bin/python -c 'import docutils'; \
rm -rf $(DOCUTILS_SRCDIR); )
symlink: python $(SYMLINKDIR)
ln -sf $(PREFIX)/bin/python $(SYMLINKDIR)/$(PYTHONNAME)$(PYTHONVER)
.PHONY: help python docutils symlink