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-reposimplestore
Test creating a consuming stream bundle v2
$ getmainid() {
> hg -R main log --template '{node}\n' --rev "$1"
> }
$ cp $HGRCPATH $TESTTMP/hgrc.orig
$ cat >> $HGRCPATH << EOF
> [experimental]
> evolution.createmarkers=True
> evolution.exchange=True
> bundle2-output-capture=True
> [ui]
> ssh="$PYTHON" "$TESTDIR/dummyssh"
> logtemplate={rev}:{node|short} {phase} {author} {bookmarks} {desc|firstline}
> [web]
> push_ssl = false
> allow_push = *
> [phases]
> publish=False
> [extensions]
> drawdag=$TESTDIR/drawdag.py
> clonebundles=
> EOF
The extension requires a repo (currently unused)
$ hg init main
$ cd main
$ hg debugdrawdag <<'EOF'
> E
> |
> D
> |
> C
> |
> B
> |
> A
> EOF
$ hg bundle -a --type="none-v2;stream=v2" bundle.hg
$ hg debugbundle bundle.hg
Stream params: {}
stream2 -- {bytecount: 1693, filecount: 11, requirements: dotencode%2Cfncache%2Cgeneraldelta%2Crevlogv1%2Cstore} (mandatory: True)
$ hg debugbundle --spec bundle.hg
none-v2;stream=v2;requirements%3Ddotencode%2Cfncache%2Cgeneraldelta%2Crevlogv1%2Cstore
Test that we can apply the bundle as a stream clone bundle
$ cat > .hg/clonebundles.manifest << EOF
> http://localhost:$HGPORT1/bundle.hg BUNDLESPEC=`hg debugbundle --spec bundle.hg`
> EOF
$ hg serve -d -p $HGPORT --pid-file hg.pid --accesslog access.log
$ cat hg.pid >> $DAEMON_PIDS
$ "$PYTHON" $TESTDIR/dumbhttp.py -p $HGPORT1 --pid http.pid
$ cat http.pid >> $DAEMON_PIDS
$ cd ..
$ hg clone http://localhost:$HGPORT streamv2-clone-implicit --debug
using http://localhost:$HGPORT/
sending capabilities command
sending clonebundles command
applying clone bundle from http://localhost:$HGPORT1/bundle.hg
bundle2-input-bundle: with-transaction
bundle2-input-part: "stream2" (params: 3 mandatory) supported
applying stream bundle
11 files to transfer, 1.65 KB of data
starting 4 threads for background file closing (?)
starting 4 threads for background file closing (?)
adding [s] data/A.i (66 bytes)
adding [s] data/B.i (66 bytes)
adding [s] data/C.i (66 bytes)
adding [s] data/D.i (66 bytes)
adding [s] data/E.i (66 bytes)
adding [s] 00manifest.i (584 bytes)
adding [s] 00changelog.i (595 bytes)
adding [s] phaseroots (43 bytes)
adding [c] branch2-served (94 bytes)
adding [c] rbc-names-v1 (7 bytes)
adding [c] rbc-revs-v1 (40 bytes)
transferred 1.65 KB in \d\.\d seconds \(.*/sec\) (re)
bundle2-input-part: total payload size 1840
bundle2-input-bundle: 0 parts total
updating the branch cache
finished applying clone bundle
query 1; heads
sending batch command
searching for changes
all remote heads known locally
no changes found
sending getbundle command
bundle2-input-bundle: with-transaction
bundle2-input-part: "listkeys" (params: 1 mandatory) supported
bundle2-input-part: "phase-heads" supported
bundle2-input-part: total payload size 24
bundle2-input-bundle: 1 parts total
checking for updated bookmarks
updating to branch default
resolving manifests
branchmerge: False, force: False, partial: False
ancestor: 000000000000, local: 000000000000+, remote: 9bc730a19041
A: remote created -> g
getting A
B: remote created -> g
getting B
C: remote created -> g
getting C
D: remote created -> g
getting D
E: remote created -> g
getting E
5 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg clone --stream http://localhost:$HGPORT streamv2-clone-explicit --debug
using http://localhost:$HGPORT/
sending capabilities command
sending clonebundles command
applying clone bundle from http://localhost:$HGPORT1/bundle.hg
bundle2-input-bundle: with-transaction
bundle2-input-part: "stream2" (params: 3 mandatory) supported
applying stream bundle
11 files to transfer, 1.65 KB of data
starting 4 threads for background file closing (?)
starting 4 threads for background file closing (?)
adding [s] data/A.i (66 bytes)
adding [s] data/B.i (66 bytes)
adding [s] data/C.i (66 bytes)
adding [s] data/D.i (66 bytes)
adding [s] data/E.i (66 bytes)
adding [s] 00manifest.i (584 bytes)
adding [s] 00changelog.i (595 bytes)
adding [s] phaseroots (43 bytes)
adding [c] branch2-served (94 bytes)
adding [c] rbc-names-v1 (7 bytes)
adding [c] rbc-revs-v1 (40 bytes)
transferred 1.65 KB in *.* seconds (*/sec) (glob)
bundle2-input-part: total payload size 1840
bundle2-input-bundle: 0 parts total
updating the branch cache
finished applying clone bundle
query 1; heads
sending batch command
searching for changes
all remote heads known locally
no changes found
sending getbundle command
bundle2-input-bundle: with-transaction
bundle2-input-part: "listkeys" (params: 1 mandatory) supported
bundle2-input-part: "phase-heads" supported
bundle2-input-part: total payload size 24
bundle2-input-bundle: 1 parts total
checking for updated bookmarks
updating to branch default
resolving manifests
branchmerge: False, force: False, partial: False
ancestor: 000000000000, local: 000000000000+, remote: 9bc730a19041
A: remote created -> g
getting A
B: remote created -> g
getting B
C: remote created -> g
getting C
D: remote created -> g
getting D
E: remote created -> g
getting E
5 files updated, 0 files merged, 0 files removed, 0 files unresolved