sparse-revlog: new requirement enabled with format.sparse-revlog
The meaning of the new 'sparse-revlog' requirement is that the revlogs are
allowed to contain wider delta chains with larger holes between the interesting
chunks. These sparse delta chains should be read in several chunks to avoid a
potential explosion of memory usage.
Former version won't know how to read a delta chain in several chunks. They
would keep reading them in a single read, and therefore would be subject to the
potential memory explosion. Hence this new requirement: only versions having
support of sparse-revlog reading should be allowed to read such a revlog.
Implementation of this new algorithm and tools to enable or disable the
requirement will follow in the next changesets.
Create a repository:
#if no-extraextensions
$ hg config
devel.all-warnings=true
devel.default-date=0 0
extensions.fsmonitor= (fsmonitor !)
largefiles.usercache=$TESTTMP/.cache/largefiles
lfs.usercache=$TESTTMP/.cache/lfs
ui.slash=True
ui.interactive=False
ui.mergemarkers=detailed
ui.promptecho=True
web.address=localhost
web\.ipv6=(?:True|False) (re)
web.server-header=testing stub value
#endif
$ hg init t
$ cd t
Prepare a changeset:
$ echo a > a
$ hg add a
$ hg status
A a
Writes to stdio succeed and fail appropriately
#if devfull
$ hg status 2>/dev/full
A a
$ hg status >/dev/full
abort: No space left on device
[255]
#endif
#if devfull
$ hg status >/dev/full 2>&1
[255]
$ hg status ENOENT 2>/dev/full
[255]
#endif
$ hg commit -m test
This command is ancient:
$ hg history
changeset: 0:acb14030fe0a
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: test
Verify that updating to revision 0 via commands.update() works properly
$ cat <<EOF > update_to_rev0.py
> from mercurial import ui, hg, commands
> myui = ui.ui.load()
> repo = hg.repository(myui, path=b'.')
> commands.update(myui, repo, rev=b"0")
> EOF
$ hg up null
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ $PYTHON ./update_to_rev0.py
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg identify -n
0
Poke around at hashes:
$ hg manifest --debug
b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3 644 a
$ hg cat a
a
Verify should succeed:
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
Repository root:
$ hg root
$TESTTMP/t
$ hg log -l1 -T '{reporoot}\n'
$TESTTMP/t
At the end...
$ cd ..