discovery-helper: use reflink copy if available
A reflink copy will copy the files "as usual" but keep using the same data block
underneath. This is only supported by "copy on write" file system like btrfs or
zfs.
This will achieve similar performance that the existing hardlink clone that
Mercurial performs with the same initial space saving. However, it will behave
better on revlogs start being touch by strip. Instead of duplicating all data in
the touched revlogs, only the block actually affected by the strip will be
duplicated. This save a lot of space when building many variants of large
repositories.
The --reflink=always flag make sure the `cp` call fails if reflink copies are
not supported. Falling back to local clone.
Setup
$ PYTHONPATH=$TESTDIR/..:$PYTHONPATH
$ export PYTHONPATH
$ cat > $TESTTMP/pretxnchangegroup.sh << EOF
> #!/bin/sh
> env | egrep "^HG_USERVAR_(DEBUG|BYPASS_REVIEW)" | sort
> exit 0
> EOF
$ cat >> $HGRCPATH << EOF
> [hooks]
> pretxnchangegroup = sh $TESTTMP/pretxnchangegroup.sh
> EOF
$ hg init repo
$ hg clone -q repo child
$ cd child
Test pushing vars to repo with pushvars.server not set
$ echo b > a
$ hg commit -Aqm a
$ hg push --pushvars "DEBUG=1" --pushvars "BYPASS_REVIEW=true"
pushing to $TESTTMP/repo
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
Setting pushvars.sever = true and then pushing.
$ echo [push] >> $HGRCPATH
$ echo "pushvars.server = true" >> $HGRCPATH
$ echo b >> a
$ hg commit -Aqm a
$ hg push --pushvars "DEBUG=1" --pushvars "BYPASS_REVIEW=true"
pushing to $TESTTMP/repo
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
HG_USERVAR_BYPASS_REVIEW=true
HG_USERVAR_DEBUG=1
Test pushing var with empty right-hand side
$ echo b >> a
$ hg commit -Aqm a
$ hg push --pushvars "DEBUG="
pushing to $TESTTMP/repo
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
HG_USERVAR_DEBUG=
Test pushing bad vars
$ echo b >> a
$ hg commit -Aqm b
$ hg push --pushvars "DEBUG"
pushing to $TESTTMP/repo
searching for changes
abort: unable to parse variable 'DEBUG', should follow 'KEY=VALUE' or 'KEY=' format
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