phases: use revision number in new_heads
All graph operations will be done using revision numbers, so passing nodes only
means they will eventually get converted to revision numbers internally.
As part of an effort to align the code on using revision number we make the
`phases.newheads` function operated on revision number, taking them as input
and using them in returns, instead of the node-id it used to consume and
produce.
This is part of multiple changesets effort to translate more part of the logic,
but is done step by step to facilitate the identification of issue that might
arise in mercurial core and extensions.
To make the change simpler to handle for third party extensions, we also rename
the function, using a more modern form. This will help detecting the different
between the node-id version and the rev-num version.
I also take this as an opportunity to add some comment about possible
performance improvement for the future. They don't matter too much now, but they
are worse exploring in a while.
Test how largefiles abort in case the disk runs full
$ cat > criple.py <<EOF
> import errno
> import os
> import shutil
> from mercurial import util
> #
> # this makes the original largefiles code abort:
> _origcopyfileobj = shutil.copyfileobj
> def copyfileobj(fsrc, fdst, length=16 * 1024):
> # allow journal files (used by transaction) to be written
> if b'journal.' in fdst.name or b'backup.' in fdst.name:
> return _origcopyfileobj(fsrc, fdst, length)
> fdst.write(fsrc.read(4))
> raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))
> shutil.copyfileobj = copyfileobj
> #
> # this makes the rewritten code abort:
> def filechunkiter(f, size=131072, limit=None):
> yield f.read(4)
> raise IOError(errno.ENOSPC, os.strerror(errno.ENOSPC))
> util.filechunkiter = filechunkiter
> #
> def oslink(src, dest):
> raise OSError("no hardlinks, try copying instead")
> util.oslink = oslink
> EOF
$ echo "[extensions]" >> $HGRCPATH
$ echo "largefiles =" >> $HGRCPATH
$ hg init alice
$ cd alice
$ echo "this is a very big file" > big
$ hg add --large big
$ hg commit --config extensions.criple=$TESTTMP/criple.py -m big
abort: No space left on device
[255]
The largefile is not created in .hg/largefiles:
$ ls .hg/largefiles
dirstate
The user cache is not even created:
>>> import os; os.path.exists("$HOME/.cache/largefiles/")
False
Make the commit with space on the device:
$ hg commit -m big
Now make a clone with a full disk, and make sure lfutil.link function
makes copies instead of hardlinks:
$ cd ..
$ hg --config extensions.criple=$TESTTMP/criple.py clone --pull alice bob
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets 390cf214e9ac
updating to branch default
getting changed largefiles
abort: No space left on device
[255]
The largefile is not created in .hg/largefiles:
$ ls bob/.hg/largefiles
dirstate