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
$ cat >> $HGRCPATH <<EOF
> [extensions]
> rebase=
>
> [phases]
> publish=False
>
> [alias]
> tglog = log -G --template "{rev}:{phase} '{desc}' {branches}\n"
> EOF
$ hg init a
$ cd a
$ echo A > A
$ hg add A
$ hg ci -m A
$ echo 'B' > B
$ hg add B
$ hg ci -m B
$ echo C >> A
$ hg ci -m C
$ hg up -q -C 0
$ echo D >> A
$ hg ci -m D
created new head
$ echo E > E
$ hg add E
$ hg ci -m E
$ hg up -q -C 0
$ hg branch 'notdefault'
marked working directory as branch notdefault
(branches are permanent and global, did you want a bookmark?)
$ echo F >> A
$ hg ci -m F
$ cd ..
Rebasing B onto E - check keep: and phases
$ hg clone -q -u . a a1
$ cd a1
$ hg phase --force --secret 2
$ hg tglog
@ 5:draft 'F' notdefault
|
| o 4:draft 'E'
| |
| o 3:draft 'D'
|/
| o 2:secret 'C'
| |
| o 1:draft 'B'
|/
o 0:draft 'A'
$ hg rebase -s 1 -d 4 --keep
rebasing 1:27547f69f254 "B"
rebasing 2:965c486023db "C"
merging A
warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
unresolved conflicts (see hg resolve, then hg rebase --continue)
[1]
Solve the conflict and go on:
$ echo 'conflict solved' > A
$ rm A.orig
$ hg resolve -m A
(no more unresolved files)
continue: hg rebase --continue
$ hg rebase --continue
already rebased 1:27547f69f254 "B" as 45396c49d53b
rebasing 2:965c486023db "C"
$ hg tglog
o 7:secret 'C'
|
o 6:draft 'B'
|
| @ 5:draft 'F' notdefault
| |
o | 4:draft 'E'
| |
o | 3:draft 'D'
|/
| o 2:secret 'C'
| |
| o 1:draft 'B'
|/
o 0:draft 'A'
$ cd ..
Rebase F onto E - check keepbranches:
$ hg clone -q -u . a a2
$ cd a2
$ hg phase --force --secret 2
$ hg tglog
@ 5:draft 'F' notdefault
|
| o 4:draft 'E'
| |
| o 3:draft 'D'
|/
| o 2:secret 'C'
| |
| o 1:draft 'B'
|/
o 0:draft 'A'
$ hg rebase -s 5 -d 4 --keepbranches
rebasing 5:01e6ebbd8272 "F" (tip)
merging A
warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
unresolved conflicts (see hg resolve, then hg rebase --continue)
[1]
Solve the conflict and go on:
$ echo 'conflict solved' > A
$ rm A.orig
$ hg resolve -m A
(no more unresolved files)
continue: hg rebase --continue
$ hg rebase --continue
rebasing 5:01e6ebbd8272 "F" (tip)
saved backup bundle to $TESTTMP/a2/.hg/strip-backup/01e6ebbd8272-6fd3a015-rebase.hg
$ hg tglog
@ 5:draft 'F' notdefault
|
o 4:draft 'E'
|
o 3:draft 'D'
|
| o 2:secret 'C'
| |
| o 1:draft 'B'
|/
o 0:draft 'A'
$ cd ..