The previous refactor to module importing broke module loading when
mercurial.* modules were loaded from a zipfile (using a zipimporter).
This scenario is likely encountered when using py2exe.
Supporting zipimporter and the traditional importer side-by-side
turns out to be quite a pain. In Python 2.x, the standard, file-based
import mechanism is partially implemented in C. The sys.meta_path
and sys.path_hooks hook points exist to allow custom importers in
Python/userland. zipimport.zipimporter and our "hgimporter" class
from earlier in this patch series are 2 of these.
In a standard Python installation (no matter if running in py2exe
or similar or not), zipimport.zipimporter appears to be registered
in sys.path_hooks. This means that as each sys.path entry is
consulted, it will ask zipimporter if it supports that path and
zipimporter will be used if that entry is a zip file. In a
py2exe environment, sys.path contains an entry with the path to
the zip file containing the Python standard library along with
Mercurial's Python files.
The way the importer mechanism works is the first importer that
declares knowledge of a module (via find_module() returning an
object) gets to load it. Since our "hgimporter" is registered
in sys.meta_path and returns an interest in specific mercurial.*
modules, the zipimporter registered on sys.path_hooks never comes
into play for these modules. So, we need to be zipimporter aware
and call into zipimporter to load modules.
This patch teaches "hgimporter" how to call out into zipimporter
when necessary. We detect the necessity of zipimporter by looking
at the loader for the "mercurial" module. If it is a zipimporter
instance, we load via zipimporter.
The behavior of zipimporter is a bit wonky.
You appear to need separate zipimporter instances for each directory
in the zip file. I'm not sure why this is. I suspect it has
something to do with the low-level importing mechanism (implemented
in C) operating on a per-directory basis. PEP-302 makes some
references to this. I was not able to get a zipimporter to
import modules outside of its immediate directory no matter how
I specified the module name. This is why we use separate
zipimporter instances for the ".zip/mercurial" and
".zip/mercurial/pure" locations.
The zipimporter documentation for Python 2.7 explicitly states that
zipimporter does not import dynamic modules (C extensions). Yet from
a py2exe distribution on Windows - where the .pyd files are *not*
in the zip archive - zipimporter imported these dynamic modules
just fine! I'm not sure if dynamic modules can't be imported from
*inside* the zip archive or whether zipimporter looks for dynamic
modules outside the zip archive. All I know is zipimporter does
manage to import the .pyd files on Windows and this patch makes
our new importer compatible with py2exe.
In the ideal world, We'd probably reimplement or fall back to parts
of the built-in import mechanism instead of handling zipimporter
specially. After all, if we're loading Mercurial modules via
something that isn't the built-in file-based importer or zipimporter,
our custom importer will likely fail because it doesn't know how to
call into it. I'd like to think that we'll never encounter this
in the wild, but you never know. If we do encounter it, we can
come up with another solution.
It's worth nothing that Python 3 has moved a lot of the importing
code from C to Python. Python 3 gives you near total control over
the import mechanism. So in the very distant future when Mercurial
drops Python 2 support, it's likely that our custom importer code
can be refactored to something a bit saner.
PyPy isn't compatible with Python C extensions.
With this patch, the module load policy is automatically to "Python
only" when run under PyPy. `hg` and other Python scripts importing
mercurial.* modules will run from the source checkout or any
installation when executed with PyPy. This should enable people to
more easily experiment with PyPy and its potentially significant
performance benefits over CPython!
With this change in place, we should have slightly stronger guarantees
about how modules with both Python and C implementations are loaded.
Before, our module loader's default policy looked under both mercurial/*
and mercurial/pure/* and imported whatever it found, C or pure. The fact
it looked in both locations by default was a temporary regression from
the beginning of this series.
This patch does 2 things:
1) Changes the default module load policy to only load C modules
2) Verifies that files loaded from mercurial/* are actually C modules
This 2nd behavior change makes our new module loading mechanism
stricter than from before this series. Before, it was possible to load
a .py-based module from mercurial/*. This could happen if an old
installation orphaned a file and then somehow didn't install the C
version for the new install. We now detect this odd configuration
and fall back to loading the pure Python module, assuming it is
allowed. In the case of a busted installation, we fail fast. While
we could fall back, we explicitly decide not to do this because
we don't want people accidentally not running the C modules and having
slow performance as a result.
Previously, .py files under mercurial/pure/ were copied to mercurial/*
during installation if we were performing a pure Python installation.
Now that the new import hooks and module load policy are in place, this
hackery from the past is no longer necessary.
With this patch, we stop copying modules from mercurial/pure/* to
mercurial/*. Instead, we preserve the files at their original
hierarchy, mirroring the source repository structure.
In addition, we always install the pure modules. Before, we would only
include the pure modules in the distribution/installation if the
install-time settings requested a pure Python installation. The upside
of this change is that CPython and PyPy can run from the same Mercurial
installation, making packaging and distribution of Mercurial simpler.
The inclusion of pure Python modules in the installation sounds
risky, as it could lead to inadvertent loading of non-C modules.
This shouldn't be a problem. The default module load policy is "C
only" (or at least will be shortly) and the only way to load pure
modules from an installation is if a) pure installation was requested
b) the HGMODULELOADPOLICY overrides the requirement for C modules.
The default module load policy as defined in source is a special string
whose default value from the checkout is equivalent to the "C only"
policy (again, not exactly the state right now). For pure
installations, this default policy is not appropriate and will not
work. This patch adds support for rewriting __init__.py during
installation to reflect the module load policy that should be in
place accoding to the installation settings. For default CPython
installs, the value in the source file will change but there will
be no functional change. For pure installations, the default policy
will be set to "py," allowing them to work without having to set
environment variables.
If we don't change this, the upcoming change to make the module
loading policy only load C modules will cause this script to fail if
run with CPython against an unbuilt source checkout.
There are a handful of modules that have both pure Python and C
extension implementations. Currently, setup.py copies files from
mercurial/pure/*.py to mercurial/ during the install process if C
extensions are not available. This way, "import mercurial.X" will
work whether C extensions are available or not.
This approach has a few drawbacks. First, there aren't run-time checks
verifying the C extensions are loaded when they should be. This could
lead to accidental use of the slower pure Python modules. Second, the
C extensions aren't compatible with PyPy and running Mercurial with
PyPy requires installing Mercurial - you can't run ./hg from a source
checkout. This makes developing while running PyPy somewhat difficult.
This patch implements a PEP-302 import hook for finding and loading the
modules with both C and Python implementations. When a module with dual
implementations is requested for import, its import is handled by our
import hook.
The importer has a mechanism that controls what types of modules we
allow to load. We call this loading behavior the "module load policy."
There are 3 settings:
* Only load C extensions
* Only load pure Python
* Try to load C and fall back to Python
An environment variable allows overriding this policy at run time. This
is mainly useful for developers and for performing actions against the
source checkout (such as installing), which require overriding the
default (strict) policy about requiring C extensions.
The default mode for now is to allow both. This isn't proper and is
technically backwards incompatible. However, it is necessary to
implement a sane patch series that doesn't break the world during
future bisections. The behavior will be corrected in future patch.
We choose the main mercurial/__init__.py module for this code out of
necessity: in a future world, if the custom module importer isn't
registered, we'll fail to find/import certain modules when running
from a pure installation. Without the magical import-time side-effects,
*any* importer of mercurial.* modules would be required to call a
function to register our importer. I'm not a fan of import time side
effects and I initially attempted to do this. However, I was foiled by
our own test harness, which has numerous `python` invoked scripts that
"import mercurial" and fail because the importer isn't registered.
Realizing this problem is probably present in random Python scripts
that have been written over the years, I decided that sacrificing
purity for backwards compatibility is necessary. Plus, if you are
programming Python, "import" should probably "just work."
It's worth noting that now that we have a custom module loader, it
would be possible to hook up demand module proxies at this level
instead of replacing __import__. We leave this work for another time,
if it's even desired.
This patch breaks importing in environments where Mercurial modules
are loaded from a zip file (such as py2exe distributions). This will
be addressed in a subsequent patch.
An upcoming change for exchanging treemanifest data will need to
update the repository capabilities, which we should only do if the
repository was empty before we started applying this changegroup. In
the future we will probably need a strategy for upgrading to
treemanifest in requires during a pull (I'm assuming at some point
we'll make it possible to have a flag day to enable treemanifests on
an existing history.)
New ui.graphnodetemplate option allows us to colorize a node symbol by phase
or branch,
[ui]
graphnodetemplate = {label('graphnode.{phase}', graphnode)}
[color]
graphnode.draft = yellow bold
or use a variety of unicode emoji characters, and so on. (You'll need less-481
to display non-BMP unicode character.)
[ui]
graphnodetemplate = {ifeq(obsolete, 'stable', graphnode, '\xf0\x9f\x92\xa9')}
This mitigates the minor perf regression introduced by the previous patch.
% hg log -G -R mozilla-central -l10000 --time > /dev/null
(original) real 2.200 secs
(previous) real 2.590 secs
(this) real 2.280 secs
This provides a default node symbol. Tests will be added later.
"showparents" variable is renamed to "wpnodes" to avoid confusion with the
existing showparents() function.
Future patches will make a node symbol templatable. Because arguments of a
templatekw function are repo and ctx, "showparents" list will have to be
built from a repo object by that function.
This allows builddeb to handle distributions that are not Debian.
Distributor ID is reported by lsb_release --id, and in case of builddeb it's
usually Debian or Ubuntu.
Debian and Ubuntu releases have both codenames and traditional version numbers.
An entire "branch" of releases is referred to by its codename, and version
numbers (e.g. 8.2, 14.04.3) are used to address individual releases.
Since we use codenames for building .deb packages, let's call the option and
the variable appropriately.
This change is replacing most of state.rules uses with state.actions
uses. The next change will change histeditstate class to actually
uses state actions.
the format of rules that we store in state file format is different from the rule
format that we present to users. We need a way of dumping action to state file.
To make histedit action objects responsible for understanding
the format of their action lines we are adding a torule method
which for a histedit action will return a string which can be
saved in histedit state or shown in text editor when editing the
plan.
This commits splits the parsing of the histedit rule from its semantic analysis.
It's necessary because sometimes we want to do first without doing the former (reading the
histedit state).
This decorator will is allowing us to move the registering the action
in actiontable closer to the action code. Also it is storing the
verb inside histedit action so the action is aware of the verb
needed to trigger it.
I want to refactor histedit to use action objects instead of (verb, rest)
pairs whenever possible. At the end of this series I want the rules to
be translated into action objects when reading state and translated back
when writing state. All histedit internals should use action objects instead
of state rules.
To migrate histedti internals sequentially I'm introducing the state.actions
property to translate rules on the fly so we can use both state.actions and
state.rules until refactoring is done.
The pull url header can easily grow over 80 chars. The check-commit script was
confusing this with a too long summary line. We update the regular expression to
not match other header.
Before this patch, "hg shelve" of shelve extension executes
'cmdutil.checkunfinished()' before acquisition of wlock.
It may cause unintentional result, if another command runs parallelly
(see also issue4368).
To avoid this issue, this patch executes 'cmdutil.checkunfinished()'
inside wlock scope of "hg shelve".
This also fixes issue4957, because now 'cmdutil.checkunfinished()'
isn't invoked at "hg shelve" with options below:
--cleanup
--delete
--list
--patch
--stat
Before this patch, "hg shelve" of shelve extension executes/refers
below before acquisition of wlock:
- 'repo.dirstate.parents()' via 'repo[None].parents()'
- 'repo._activebookmark'
It may cause unintentional result, if another command runs parallelly
(see also issue4368).
This patch widens wlock scope of "hg shelve" of shelve extension for
consistency while processing.
Before this patch, "hg sign" of gpg extension executes/evaluates below
without acquisition of wlock.
- repo.dirstate.parents()
- '.hgsigs' not in repo.dirstate
It may cause unintentional result, if another command runs parallelly
(see also issue4368).
To avoid this issue, this patch makes "hg sign" of gpg extension
acquire wlock before processing.
Before this patch, "hg import" executes below before acquisition of
wlock:
- cmdutil.checkunfinished()
- cmdutil.bailifchanged()
It may cause unintentional result, if another command runs parallelly
(see also issue4368).
To avoid this issue, this patch executes 'cmdutil.checkunfinished()'
and 'cmdutil.bailifchanged()' inside wlock scope of "hg import".
Before this patch, "hg graft" executes below before acquisition of
wlock.
- cmdutil.checkunfinished()
- cmdutil.bailifchanged()
- repo.dirstate.parents() via 'repo["."]'
- unlinking '.hg/graftstate'
It may cause unintentional result, if another command runs parallelly
(see also issue4368).
This patch widens wlock scope of "hg graft" for consitency while
processing.
Before this patch, "hg backout" executes below before acquisition of
wlock.
- cmdutil.checkunfinished()
- cmdutil.bailifchanged()
- repo.dirstate.parents()
It may cause unintentional result, if another command runs parallelly
(see also issue4368).
In addition to it, "hg backout" refers changelog for purposes below
without acquisition of store lock (slock), and it may cause
unintentional result, if store is updated parallelly.
- show and update to the revision by 'repo.changelog.tip()'
- examine for "created new head" by 'repo.branchheads()' and
'cmdutil.commitstatus()'
To avoid this issue, this patch makes "hg backout" acquire wlock and
slock before processing.
Before this patch, "hg commit" (process A) executes steps below:
1. get current branch heads via 'repo.branchheads()'
- cache 'repo.changelog'
2. invoke 'repo.commit()'
3. acquire wlock
- invalidate 'repo.dirstate'
4. access 'repo.dirstate'
- re-read '.hg/dirstate'
- check validity of parent revisions with 'repo.changelog'
5. invoke 'repo.commitctx()'
6. acquire store lock (slock)
- invalidate 'repo.changelog'
7. do committing
8. release slock
9. release wlock
10. check new branch head (via 'cmdutil.commitstatus()')
If acquisition of wlock at (3) above waits for another "hg commit"
(process B) or so running parallelly to release wlock, process A
causes creating orphan revision, because:
- '.hg/dirstate' refers the revision, which is newly added by
process B, as its parent
- but already cached 'repo.changelog' doesn't contain such revision
- therefore, validating parents of '.hg/dirstate' at (4) above
replaces such revision with 'nullid'
Then, process A creates "orphan" revision, of which parent is "null"
revision.
In addition to it, "created new head" may be shown at the end of
process A unintentionally, if store is updated parallelly, because
both getting branch heads (1) and checking new branch head (10) are
executed outside slock scope.
To avoid this issue, this patch makes "hg commit" acquire wlock and
slock before processing.
This patch resolves the issue between "hg commit" processes, but not
one between "hg commit" and other commands. Subsequent patches resolve
the latter.
Even after this patch, there are still corner case problems below:
- filecache may overlook changes of '.hg/dirstate', and it causes
similar issue (see below for detail)
https://bz.mercurial-scm.org/show_bug.cgi?id=4368#c10
- 3rd party extension may cause similar issue, if it directly uses
'repo.commit()' without acquisition of wlock and slock
This can be fixed by acquisition of slock at the beginning of
'repo.commit()', but it seems suitable for "default" branch
In fact, acquisition of slock itself is already introduced at
"default" branch by ec227b188932, but acquisition is not at the
beginning of 'repo.commit()'.
This patch also changes some tests:
- test-fncache.t needs this tricky wrapping, to release (= forced
failure of) wlock certainly
- order of "hg commit" output is changed by widening scope of locks,
because some hooks are fired after releasing wlock
We unify the delta selection process to be a simple three options process:
- try to use the incoming delta (if lazydeltabase is on)
- try to find a suitable parents to delta against (if gd is on)
- try to delta against the tipmost revision
The first of this option that yield a valid delta will be used.
The test change in 'test-generaldelta.t' show this behavior as we use a delta
against the parent instead of a full delta when the incoming delta is not
suitable.
This as some impact on 'test-bundle.t' because a delta somewhere changes. It
does not seems to change the test semantic and have been ignored.
The currently used manifest is too small and cannot sustain a chain length
above "1". This make testing the 'lazybasedelta' behavior hard. So we add an
extra file in the manifest to help testing in the next changeset.
The semantic of existing tests have been checked and is not changed.
The old code have multiple explicit tests and code duplications. This makes it
hard to improve the code. We rewrite the logic in a more generic way, not
changing anything of the computed result.
The final goal here is to eventually be able to:
- factor out the default fallback case "try against 'prev'" in a single place
- allow 'lazydeltabase' case to use the smarter general delta code path when
the incoming base does not provide us with a good delta.
I'm about to move active-bookmark management into the bmstore. I'd
like to avoid re-writing the bookmarks data (as distinct from the
active bookmark file) if possible, so let's introduce some
dirty-tracking early.
Previously, when extdiff was called on two changesets where
a subrepository had been removed, an unexpected KeyError would
be raised.
Now, the missing subrepository will be ignored. This behavior
mirrors the behavior in diffordiffstat from cmdutil.py line
~1138-1153. The KeyError is caught and the revision is
set to None.
try/catch of LookupError around matchmod.narrowmatcher and
sub.status is removed, as LookupError is not raised anywhere
within those methods or deeper calls.
Before this patch, it was unclear why the httpservice object could read the
server options (e.g. --port) from 'ui'. It just worked because repo.ui is ui.
Since createservice() was moved to hgweb and hgweb imports both hgweb_mod and
hgwebdir_mod, we no longer have to force hgweb() function to select one of
them by the type of 'o' variable. Let's be explicit!
This patch does not change hgweb() function because it is the interface of
existing WSGI and CGI scripts.
Before this change, the 'lazydeltabase' would blindly build a delta using the
base provided by the incoming bundle and try to use it. If that base was far
down the revlog, the delta would be seen as "no good" and we would fall back to
a full text revision.
We now check if the delta is good and fallback to a computing a delta again the
tipmost revision otherwise (as we would do without general delta).
Later changesets will improve the logic to compute the fallback delta using the
general delta logic.
We would like to be able to exit the delta generation block without a valid
delta (for a more flexible control flow). So we make sure we do not expand the
"delta" content unless we actually have a delta.
We can do it one level lower because 'delta' is initialised at None anyway. Not
adding a level to the assignment prevent a line length issue.
When strip builds the list of changedfiles to pass into dirstate.rebuild, it adds
files blindly, including those that have been removed. This tests ensures that
rebuild can handle this case.
When debugrebuilddirstate --minimal is called, rebuilding the dirstate was done
outside of the appropriate rebuild function. This patch makes
debugrebuilddirstate use dirstate.rebuild.
This was done to allow our extension to become aware debugrebuilddirstate
--minimal
