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 << EOF > buggylocking.py
> """A small extension that tests our developer warnings
> """
>
> from mercurial import error, registrar, repair, util
>
> cmdtable = {}
> command = registrar.command(cmdtable)
>
> @command(b'buggylocking', [], '')
> def buggylocking(ui, repo):
> lo = repo.lock()
> wl = repo.wlock()
> wl.release()
> lo.release()
>
> @command(b'buggytransaction', [], '')
> def buggylocking(ui, repo):
> tr = repo.transaction(b'buggy')
> # make sure we rollback the transaction as we don't want to rely on the__del__
> tr.release()
>
> @command(b'properlocking', [], '')
> def properlocking(ui, repo):
> """check that reentrance is fine"""
> wl = repo.wlock()
> lo = repo.lock()
> tr = repo.transaction(b'proper')
> tr2 = repo.transaction(b'proper')
> lo2 = repo.lock()
> wl2 = repo.wlock()
> wl2.release()
> lo2.release()
> tr2.close()
> tr.close()
> lo.release()
> wl.release()
>
> @command(b'nowaitlocking', [], '')
> def nowaitlocking(ui, repo):
> lo = repo.lock()
> wl = repo.wlock(wait=False)
> wl.release()
> lo.release()
>
> @command(b'no-wlock-write', [], '')
> def nowlockwrite(ui, repo):
> with repo.vfs(b'branch', b'a'):
> pass
>
> @command(b'no-lock-write', [], '')
> def nolockwrite(ui, repo):
> with repo.svfs(b'fncache', b'a'):
> pass
>
> @command(b'stripintr', [], '')
> def stripintr(ui, repo):
> lo = repo.lock()
> tr = repo.transaction(b'foobar')
> try:
> repair.strip(repo.ui, repo, [repo[b'.'].node()])
> finally:
> lo.release()
> @command(b'oldanddeprecated', [], '')
> def oldanddeprecated(ui, repo):
> """test deprecation warning API"""
> def foobar(ui):
> ui.deprecwarn(b'foorbar is deprecated, go shopping', b'42.1337')
> foobar(ui)
> @command(b'nouiwarning', [], '')
> def nouiwarning(ui, repo):
> util.nouideprecwarn(b'this is a test', b'13.37')
> @command(b'programmingerror', [], '')
> def programmingerror(ui, repo):
> raise error.ProgrammingError(b'something went wrong', hint=b'try again')
> EOF
$ cat << EOF >> $HGRCPATH
> [extensions]
> buggylocking=$TESTTMP/buggylocking.py
> mock=$TESTDIR/mockblackbox.py
> blackbox=
> [devel]
> all-warnings=1
> EOF
$ hg init lock-checker
$ cd lock-checker
$ hg buggylocking
devel-warn: "wlock" acquired after "lock" at: $TESTTMP/buggylocking.py:* (buggylocking) (glob)
$ cat << EOF >> $HGRCPATH
> [devel]
> all=0
> check-locks=1
> EOF
$ hg buggylocking
devel-warn: "wlock" acquired after "lock" at: $TESTTMP/buggylocking.py:* (buggylocking) (glob)
#if no-chg
$ hg buggylocking --traceback
devel-warn: "wlock" acquired after "lock" at:
*/hg:* in <module> (glob) (?)
*/mercurial/dispatch.py:* in run (glob)
*/mercurial/dispatch.py:* in dispatch (glob)
*/mercurial/dispatch.py:* in _runcatch (glob)
*/mercurial/dispatch.py:* in _callcatch (glob)
*/mercurial/scmutil.py* in callcatch (glob)
*/mercurial/dispatch.py:* in _runcatchfunc (glob)
*/mercurial/dispatch.py:* in _dispatch (glob)
*/mercurial/dispatch.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in _runcommand (glob)
*/mercurial/dispatch.py:* in <lambda> (glob)
*/mercurial/util.py:* in check (glob)
$TESTTMP/buggylocking.py:* in buggylocking (glob)
#else
$ hg buggylocking --traceback
devel-warn: "wlock" acquired after "lock" at:
*/hg:* in <module> (glob) (?)
*/mercurial/dispatch.py:* in run (glob)
*/mercurial/dispatch.py:* in dispatch (glob)
*/mercurial/dispatch.py:* in _runcatch (glob)
*/mercurial/dispatch.py:* in _callcatch (glob)
*/mercurial/scmutil.py:* in callcatch (glob)
*/mercurial/dispatch.py:* in _runcatchfunc (glob)
*/mercurial/dispatch.py:* in _dispatch (glob)
*/mercurial/dispatch.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in _runcommand (glob)
*/mercurial/dispatch.py:* in <lambda> (glob)
*/mercurial/util.py:* in check (glob)
*/mercurial/commands.py:* in serve (glob)
*/mercurial/server.py:* in runservice (glob)
*/mercurial/commandserver.py:* in run (glob)
*/mercurial/commandserver.py:* in _mainloop (glob)
*/mercurial/commandserver.py:* in _runworker (glob)
*/mercurial/commandserver.py:* in _serverequest (glob)
*/mercurial/commandserver.py:* in serve (glob)
*/mercurial/commandserver.py:* in serveone (glob)
*/mercurial/chgserver.py:* in runcommand (glob)
*/mercurial/commandserver.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in dispatch (glob)
*/mercurial/dispatch.py:* in _runcatch (glob)
*/mercurial/dispatch.py:* in _callcatch (glob)
*/mercurial/scmutil.py:* in callcatch (glob)
*/mercurial/dispatch.py:* in _runcatchfunc (glob)
*/mercurial/dispatch.py:* in _dispatch (glob)
*/mercurial/dispatch.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in _runcommand (glob)
*/mercurial/dispatch.py:* in <lambda> (glob)
*/mercurial/util.py:* in check (glob)
$TESTTMP/buggylocking.py:* in buggylocking (glob)
#endif
$ hg properlocking
$ hg nowaitlocking
Writing without lock
$ hg no-wlock-write
devel-warn: write with no wlock: "branch" at: $TESTTMP/buggylocking.py:* (nowlockwrite) (glob)
$ hg no-lock-write
devel-warn: write with no lock: "fncache" at: $TESTTMP/buggylocking.py:* (nolockwrite) (glob)
Stripping from a transaction
$ echo a > a
$ hg add a
$ hg commit -m a
$ hg stripintr 2>&1 | egrep -v '^(\*\*| )'
Traceback (most recent call last):
*ProgrammingError: cannot strip from inside a transaction (glob)
$ hg oldanddeprecated
devel-warn: foorbar is deprecated, go shopping
(compatibility will be dropped after Mercurial-42.1337, update your code.) at: $TESTTMP/buggylocking.py:* (oldanddeprecated) (glob)
#if no-chg
$ hg oldanddeprecated --traceback
devel-warn: foorbar is deprecated, go shopping
(compatibility will be dropped after Mercurial-42.1337, update your code.) at:
*/hg:* in <module> (glob) (?)
*/mercurial/dispatch.py:* in run (glob)
*/mercurial/dispatch.py:* in dispatch (glob)
*/mercurial/dispatch.py:* in _runcatch (glob)
*/mercurial/dispatch.py:* in _callcatch (glob)
*/mercurial/scmutil.py* in callcatch (glob)
*/mercurial/dispatch.py:* in _runcatchfunc (glob)
*/mercurial/dispatch.py:* in _dispatch (glob)
*/mercurial/dispatch.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in _runcommand (glob)
*/mercurial/dispatch.py:* in <lambda> (glob)
*/mercurial/util.py:* in check (glob)
$TESTTMP/buggylocking.py:* in oldanddeprecated (glob)
#else
$ hg oldanddeprecated --traceback
devel-warn: foorbar is deprecated, go shopping
(compatibility will be dropped after Mercurial-42.1337, update your code.) at:
*/hg:* in <module> (glob)
*/mercurial/dispatch.py:* in run (glob)
*/mercurial/dispatch.py:* in dispatch (glob)
*/mercurial/dispatch.py:* in _runcatch (glob)
*/mercurial/dispatch.py:* in _callcatch (glob)
*/mercurial/scmutil.py:* in callcatch (glob)
*/mercurial/dispatch.py:* in _runcatchfunc (glob)
*/mercurial/dispatch.py:* in _dispatch (glob)
*/mercurial/dispatch.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in _runcommand (glob)
*/mercurial/dispatch.py:* in <lambda> (glob)
*/mercurial/util.py:* in check (glob)
*/mercurial/commands.py:* in serve (glob)
*/mercurial/server.py:* in runservice (glob)
*/mercurial/commandserver.py:* in run (glob)
*/mercurial/commandserver.py:* in _mainloop (glob)
*/mercurial/commandserver.py:* in _runworker (glob)
*/mercurial/commandserver.py:* in _serverequest (glob)
*/mercurial/commandserver.py:* in serve (glob)
*/mercurial/commandserver.py:* in serveone (glob)
*/mercurial/chgserver.py:* in runcommand (glob)
*/mercurial/commandserver.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in dispatch (glob)
*/mercurial/dispatch.py:* in _runcatch (glob)
*/mercurial/dispatch.py:* in _callcatch (glob)
*/mercurial/scmutil.py:* in callcatch (glob)
*/mercurial/dispatch.py:* in _runcatchfunc (glob)
*/mercurial/dispatch.py:* in _dispatch (glob)
*/mercurial/dispatch.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in _runcommand (glob)
*/mercurial/dispatch.py:* in <lambda> (glob)
*/mercurial/util.py:* in check (glob)
$TESTTMP/buggylocking.py:* in oldanddeprecated (glob)
#endif
#if no-chg
$ hg blackbox -l 7
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> oldanddeprecated
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> devel-warn: foorbar is deprecated, go shopping
(compatibility will be dropped after Mercurial-42.1337, update your code.) at: $TESTTMP/buggylocking.py:* (oldanddeprecated) (glob)
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> oldanddeprecated exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> oldanddeprecated --traceback
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> devel-warn: foorbar is deprecated, go shopping
(compatibility will be dropped after Mercurial-42.1337, update your code.) at:
*/hg:* in <module> (glob) (?)
*/mercurial/dispatch.py:* in run (glob)
*/mercurial/dispatch.py:* in dispatch (glob)
*/mercurial/dispatch.py:* in _runcatch (glob)
*/mercurial/dispatch.py:* in _callcatch (glob)
*/mercurial/scmutil.py* in callcatch (glob)
*/mercurial/dispatch.py:* in _runcatchfunc (glob)
*/mercurial/dispatch.py:* in _dispatch (glob)
*/mercurial/dispatch.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in _runcommand (glob)
*/mercurial/dispatch.py:* in <lambda> (glob)
*/mercurial/util.py:* in check (glob)
$TESTTMP/buggylocking.py:* in oldanddeprecated (glob)
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> oldanddeprecated --traceback exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> blackbox -l 7
#else
$ hg blackbox -l 7
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> oldanddeprecated
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> devel-warn: foorbar is deprecated, go shopping
(compatibility will be dropped after Mercurial-42.1337, update your code.) at: $TESTTMP/buggylocking.py:* (oldanddeprecated) (glob)
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> oldanddeprecated exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> oldanddeprecated --traceback
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> devel-warn: foorbar is deprecated, go shopping
(compatibility will be dropped after Mercurial-42.1337, update your code.) at:
*/hg:* in <module> (glob)
*/mercurial/dispatch.py:* in run (glob)
*/mercurial/dispatch.py:* in dispatch (glob)
*/mercurial/dispatch.py:* in _runcatch (glob)
*/mercurial/dispatch.py:* in _callcatch (glob)
*/mercurial/scmutil.py:* in callcatch (glob)
*/mercurial/dispatch.py:* in _runcatchfunc (glob)
*/mercurial/dispatch.py:* in _dispatch (glob)
*/mercurial/dispatch.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in _runcommand (glob)
*/mercurial/dispatch.py:* in <lambda> (glob)
*/mercurial/util.py:* in check (glob)
*/mercurial/commands.py:* in serve (glob)
*/mercurial/server.py:* in runservice (glob)
*/mercurial/commandserver.py:* in run (glob)
*/mercurial/commandserver.py:* in _mainloop (glob)
*/mercurial/commandserver.py:* in _runworker (glob)
*/mercurial/commandserver.py:* in _serverequest (glob)
*/mercurial/commandserver.py:* in serve (glob)
*/mercurial/commandserver.py:* in serveone (glob)
*/mercurial/chgserver.py:* in runcommand (glob)
*/mercurial/commandserver.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in dispatch (glob)
*/mercurial/dispatch.py:* in _runcatch (glob)
*/mercurial/dispatch.py:* in _callcatch (glob)
*/mercurial/scmutil.py:* in callcatch (glob)
*/mercurial/dispatch.py:* in _runcatchfunc (glob)
*/mercurial/dispatch.py:* in _dispatch (glob)
*/mercurial/dispatch.py:* in runcommand (glob)
*/mercurial/dispatch.py:* in _runcommand (glob)
*/mercurial/dispatch.py:* in <lambda> (glob)
*/mercurial/util.py:* in check (glob)
$TESTTMP/buggylocking.py:* in oldanddeprecated (glob)
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> oldanddeprecated --traceback exited 0 after * seconds (glob)
1970/01/01 00:00:00 bob @cb9a9f314b8b07ba71012fcdbc544b5a4d82ff5b (5000)> blackbox -l 7
#endif
Test programming error failure:
$ hg buggytransaction 2>&1 | egrep -v '^ '
** Unknown exception encountered with possibly-broken third-party extension buggylocking
** which supports versions unknown of Mercurial.
** Please disable buggylocking and try your action again.
** If that fixes the bug please report it to the extension author.
** Python * (glob)
** Mercurial Distributed SCM (*) (glob)
** Extensions loaded: * (glob)
** ProgrammingError: transaction requires locking
Traceback (most recent call last):
*ProgrammingError: transaction requires locking (glob)
$ hg programmingerror 2>&1 | egrep -v '^ '
** Unknown exception encountered with possibly-broken third-party extension buggylocking
** which supports versions unknown of Mercurial.
** Please disable buggylocking and try your action again.
** If that fixes the bug please report it to the extension author.
** Python * (glob)
** Mercurial Distributed SCM (*) (glob)
** Extensions loaded: * (glob)
** ProgrammingError: something went wrong
** (try again)
Traceback (most recent call last):
*ProgrammingError: something went wrong (glob)
Old style deprecation warning
$ hg nouiwarning
$TESTTMP/buggylocking.py:*: DeprecationWarning: this is a test (glob)
(compatibility will be dropped after Mercurial-13.37, update your code.)
util.nouideprecwarn(b'this is a test', b'13.37')
(disabled outside of test run)
$ HGEMITWARNINGS= hg nouiwarning
Test warning on config option access and registration
$ cat << EOF > ${TESTTMP}/buggyconfig.py
> """A small extension that tests our developer warnings for config"""
>
> from mercurial import registrar, configitems
>
> cmdtable = {}
> command = registrar.command(cmdtable)
>
> configtable = {}
> configitem = registrar.configitem(configtable)
>
> configitem(b'test', b'some', default=b'foo')
> configitem(b'test', b'dynamic', default=configitems.dynamicdefault)
> configitem(b'test', b'callable', default=list)
> # overwrite a core config
> configitem(b'ui', b'quiet', default=False)
> configitem(b'ui', b'interactive', default=None)
>
> @command(b'buggyconfig')
> def cmdbuggyconfig(ui, repo):
> repo.ui.config(b'ui', b'quiet', True)
> repo.ui.config(b'ui', b'interactive', False)
> repo.ui.config(b'test', b'some', b'bar')
> repo.ui.config(b'test', b'some', b'foo')
> repo.ui.config(b'test', b'dynamic', b'some-required-default')
> repo.ui.config(b'test', b'dynamic')
> repo.ui.config(b'test', b'callable', [])
> repo.ui.config(b'test', b'callable', b'foo')
> repo.ui.config(b'test', b'unregistered')
> repo.ui.config(b'unregistered', b'unregistered')
> EOF
$ hg --config "extensions.buggyconfig=${TESTTMP}/buggyconfig.py" buggyconfig
devel-warn: extension 'buggyconfig' overwrite config item 'ui.interactive' at: */mercurial/extensions.py:* (_loadextra) (glob)
devel-warn: extension 'buggyconfig' overwrite config item 'ui.quiet' at: */mercurial/extensions.py:* (_loadextra) (glob)
devel-warn: specifying a mismatched default value for a registered config item: 'ui.quiet' 'True' at: $TESTTMP/buggyconfig.py:* (cmdbuggyconfig) (glob)
devel-warn: specifying a mismatched default value for a registered config item: 'ui.interactive' 'False' at: $TESTTMP/buggyconfig.py:* (cmdbuggyconfig) (glob)
devel-warn: specifying a mismatched default value for a registered config item: 'test.some' 'bar' at: $TESTTMP/buggyconfig.py:* (cmdbuggyconfig) (glob)
devel-warn: config item requires an explicit default value: 'test.dynamic' at: $TESTTMP/buggyconfig.py:* (cmdbuggyconfig) (glob)
devel-warn: specifying a mismatched default value for a registered config item: 'test.callable' 'foo' at: $TESTTMP/buggyconfig.py:* (cmdbuggyconfig) (glob)
devel-warn: accessing unregistered config item: 'test.unregistered' at: $TESTTMP/buggyconfig.py:* (cmdbuggyconfig) (glob)
devel-warn: accessing unregistered config item: 'unregistered.unregistered' at: $TESTTMP/buggyconfig.py:* (cmdbuggyconfig) (glob)
$ cd ..