internals: document CBOR utilization
I spoke with some people at Mozilla about CBOR and they advised me
that we should be careful about the subset of CBOR we use in order
to mitigate security, performance, and compatibility concerns.
This commit establishes a document that attempts to formalize our
use of CBOR.
Its main limitations are on what types are allowed. It explicitly
enumerates which types are supported. Notable missing features
include:
* Indefinite-length arrays and maps
* Text strings (bytes all the way)
* Floats
* Date/time types
* Big integers
* Use of indefinite-length byte strings for map keys, values in
containers.
If we have a need for any of these, we can have a discussion about
them when the time comes.
Differential Revision: https://phab.mercurial-scm.org/D4412
#require no-chg
$ hg init repo
$ cd repo
$ echo foo > foo
$ hg ci -qAm 'add foo'
$ echo >> foo
$ hg ci -m 'change foo'
$ hg up -qC 0
$ echo bar > bar
$ hg ci -qAm 'add bar'
$ hg log
changeset: 2:effea6de0384
tag: tip
parent: 0:bbd179dfa0a7
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: add bar
changeset: 1:ed1b79f46b9a
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: change foo
changeset: 0:bbd179dfa0a7
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: add foo
$ cd ..
Test pullbundle functionality
$ cd repo
$ cat <<EOF > .hg/hgrc
> [server]
> pullbundle = True
> [extensions]
> blackbox =
> EOF
$ hg bundle --base null -r 0 .hg/0.hg
1 changesets found
$ hg bundle --base 0 -r 1 .hg/1.hg
1 changesets found
$ hg bundle --base 1 -r 2 .hg/2.hg
1 changesets found
$ cat <<EOF > .hg/pullbundles.manifest
> 2.hg BUNDLESPEC=none-v2 heads=effea6de0384e684f44435651cb7bd70b8735bd4 bases=bbd179dfa0a71671c253b3ae0aa1513b60d199fa
> 1.hg BUNDLESPEC=bzip2-v2 heads=ed1b79f46b9a29f5a6efa59cf12fcfca43bead5a bases=bbd179dfa0a71671c253b3ae0aa1513b60d199fa
> 0.hg BUNDLESPEC=gzip-v2 heads=bbd179dfa0a71671c253b3ae0aa1513b60d199fa
> EOF
$ hg --config blackbox.track=debug --debug serve -p $HGPORT2 -d --pid-file=../repo.pid
listening at http://*:$HGPORT2/ (bound to $LOCALIP:$HGPORT2) (glob) (?)
$ cat ../repo.pid >> $DAEMON_PIDS
$ cd ..
$ hg clone -r 0 http://localhost:$HGPORT2/ repo.pullbundle
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets bbd179dfa0a7
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd repo.pullbundle
$ hg pull -r 1
pulling from http://localhost:$HGPORT2/
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets ed1b79f46b9a
(run 'hg update' to get a working copy)
$ hg pull -r 2
pulling from http://localhost:$HGPORT2/
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets effea6de0384
(run 'hg heads' to see heads, 'hg merge' to merge)
$ cd ..
$ killdaemons.py
$ grep 'sending pullbundle ' repo/.hg/blackbox.log
* sending pullbundle "0.hg" (glob)
* sending pullbundle "1.hg" (glob)
* sending pullbundle "2.hg" (glob)
$ rm repo/.hg/blackbox.log
Test pullbundle functionality for incremental pulls
$ cd repo
$ hg --config blackbox.track=debug --debug serve -p $HGPORT2 -d --pid-file=../repo.pid
listening at http://*:$HGPORT2/ (bound to $LOCALIP:$HGPORT2) (glob) (?)
$ cat ../repo.pid >> $DAEMON_PIDS
$ cd ..
$ hg clone http://localhost:$HGPORT2/ repo.pullbundle2
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
new changesets bbd179dfa0a7:ed1b79f46b9a
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ killdaemons.py
$ grep 'sending pullbundle ' repo/.hg/blackbox.log
* sending pullbundle "0.hg" (glob)
* sending pullbundle "2.hg" (glob)
* sending pullbundle "1.hg" (glob)
$ rm repo/.hg/blackbox.log
Test recovery from misconfigured server sending no new data
$ cd repo
$ cat <<EOF > .hg/pullbundles.manifest
> 0.hg heads=ed1b79f46b9a29f5a6efa59cf12fcfca43bead5a bases=bbd179dfa0a71671c253b3ae0aa1513b60d199fa
> 0.hg heads=bbd179dfa0a71671c253b3ae0aa1513b60d199fa
> EOF
$ hg --config blackbox.track=debug --debug serve -p $HGPORT2 -d --pid-file=../repo.pid
listening at http://*:$HGPORT2/ (bound to $LOCALIP:$HGPORT2) (glob) (?)
$ cat ../repo.pid >> $DAEMON_PIDS
$ cd ..
$ hg clone -r 0 http://localhost:$HGPORT2/ repo.pullbundle3
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets bbd179dfa0a7
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd repo.pullbundle3
$ hg pull -r 1
pulling from http://localhost:$HGPORT2/
searching for changes
adding changesets
adding manifests
adding file changes
added 0 changesets with 0 changes to 1 files
abort: 00changelog.i@ed1b79f46b9a: no node!
[255]
$ cd ..
$ killdaemons.py
$ grep 'sending pullbundle ' repo/.hg/blackbox.log
* sending pullbundle "0.hg" (glob)
* sending pullbundle "0.hg" (glob)
$ rm repo/.hg/blackbox.log