1
============================
2
Guidelines for modifying bzr
3
============================
7
(The current version of this document is available in the file ``HACKING``
8
in the source tree, or at http://doc.bazaar-vcs.org/current/hacking.html)
13
* New functionality should have test cases. Preferably write the
14
test before writing the code.
16
In general, you can test at either the command-line level or the
17
internal API level. See Writing Tests below for more detail.
19
* Try to practice Test-Driven Development. before fixing a bug, write a
20
test case so that it does not regress. Similarly for adding a new
21
feature: write a test case for a small version of the new feature before
22
starting on the code itself. Check the test fails on the old code, then
23
add the feature or fix and check it passes.
25
* Exceptions should be defined inside bzrlib.errors, so that we can
26
see the whole tree at a glance.
28
* Imports should be done at the top-level of the file, unless there is
29
a strong reason to have them lazily loaded when a particular
30
function runs. Import statements have a cost, so try to make sure
31
they don't run inside hot functions.
33
* Module names should always be given fully-qualified,
34
i.e. ``bzrlib.hashcache`` not just ``hashcache``.
36
* Commands should return non-zero when they encounter circumstances that
37
the user should really pay attention to - which includes trivial shell
40
Recommended values are
42
1. Conflicts in merge-like operations, or changes are present in
44
2. Unrepresentable diff changes (i.e. binary files that we cannot show
46
3. An error or exception has occurred.
51
We have a commitment to 6 months API stability - any supported symbol in a
52
release of bzr MUST NOT be altered in any way that would result in
5
This document describes the Bazaar internals and the development process.
6
It's meant for people interested in developing Bazaar, and some parts will
7
also be useful to people developing Bazaar plugins.
9
If you have any questions or something seems to be incorrect, unclear or
10
missing, please talk to us in ``irc://irc.freenode.net/#bzr``, or write to
11
the Bazaar mailing list. To propose a correction or addition to this
12
document, send a merge request or new text to the mailing list.
14
The latest developer documentation can be found online at
15
http://doc.bazaar.canonical.com/developers/.
20
Exploring the Bazaar Platform
21
=============================
23
Before making changes, it's a good idea to explore the work already
24
done by others. Perhaps the new feature or improvement you're looking
25
for is available in another plug-in already? If you find a bug,
26
perhaps someone else has already fixed it?
28
To answer these questions and more, take a moment to explore the
29
overall Bazaar Platform. Here are some links to browse:
31
* The Plugins page on the Wiki - http://wiki.bazaar.canonical.com/BzrPlugins
33
* The Bazaar product family on Launchpad - https://launchpad.net/bazaar
35
* Bug Tracker for the core product - https://bugs.launchpad.net/bzr/
37
If nothing else, perhaps you'll find inspiration in how other developers
38
have solved their challenges.
40
Finding Something To Do
41
=======================
43
Ad-hoc performance work can also be done. One useful tool is the 'evil' debug
44
flag. For instance running ``bzr -Devil commit -m "test"`` will log a backtrace
45
to the bzr log file for every method call which triggers a slow or non-scalable
46
part of the bzr library. So checking that a given command with ``-Devil`` has
47
no backtraces logged to the log file is a good way to find problem function
48
calls that might be nested deep in the code base.
50
Planning and Discussing Changes
51
===============================
53
There is a very active community around Bazaar. Mostly we meet on IRC
54
(#bzr on irc.freenode.net) and on the mailing list. To join the Bazaar
55
community, see http://wiki.bazaar.canonical.com/BzrSupport.
57
If you are planning to make a change, it's a very good idea to mention it
58
on the IRC channel and/or on the mailing list. There are many advantages
59
to involving the community before you spend much time on a change.
62
* you get to build on the wisdom of others, saving time
64
* if others can direct you to similar code, it minimises the work to be done
66
* it assists everyone in coordinating direction, priorities and effort.
68
In summary, maximising the input from others typically minimises the
69
total effort required to get your changes merged. The community is
70
friendly, helpful and always keen to welcome newcomers.
73
Bazaar Development in a Nutshell
74
================================
76
.. was from http://wiki.bazaar.canonical.com/BzrGivingBack
78
One of the fun things about working on a version control system like Bazaar is
79
that the users have a high level of proficiency in contributing back into
80
the tool. Consider the following very brief introduction to contributing back
81
to Bazaar. More detailed instructions are in the following sections.
86
First, get a local copy of the development mainline (See `Why make a local
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$ bzr branch lp:bzr bzr.dev
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Now make your own branch::
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$ bzr branch bzr.dev 123456-my-bugfix
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This will give you a branch called "123456-my-bugfix" that you can work on
99
and commit in. Here, you can study the code, make a fix or a new feature.
100
Feel free to commit early and often (after all, it's your branch!).
102
Documentation improvements are an easy place to get started giving back to the
103
Bazaar project. The documentation is in the `doc/` subdirectory of the Bazaar
106
When you are done, make sure that you commit your last set of changes as well!
107
Once you are happy with your changes, ask for them to be merged, as described
110
Making a Merge Proposal
111
-----------------------
113
The Bazaar developers use Launchpad to further enable a truly distributed
114
style of development. Anyone can propose a branch for merging into the Bazaar
115
trunk. To start this process, you need to push your branch to Launchpad. To
116
do this, you will need a Launchpad account and user name, e.g.
117
`your_lp_username`. You can push your branch to Launchpad directly from
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$ bzr push lp:~<your_lp_username>/bzr/meaningful_name_here
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After you have pushed your branch, you will need to propose it for merging to
123
the Bazaar trunk. Go to
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<https://launchpad.net/~<your_lp_username>/bzr/meaningful_name_here> and choose
125
"Propose for merging into another branch". Select "lp:bzr" to hand
126
your changes off to the Bazaar developers for review and merging.
128
Alternatively, after pushing you can use the ``lp-propose`` command to
129
create the merge proposal.
131
Using a meaningful name for your branch will help you and the reviewer(s)
132
better track the submission. Use a very succint description of your submission
133
and prefix it with bug number if needed (lp:~mbp/bzr/484558-merge-directory
134
for example). Alternatively, you can suffix with the bug number
135
(lp:~jameinel/bzr/export-file-511987).
141
Please put a "cover letter" on your merge request explaining:
143
* the reason **why** you're making this change
145
* **how** this change achieves this purpose
147
* anything else you may have fixed in passing
149
* anything significant that you thought of doing, such as a more
150
extensive fix or a different approach, but didn't or couldn't do now
152
A good cover letter makes reviewers' lives easier because they can decide
153
from the letter whether they agree with the purpose and approach, and then
154
assess whether the patch actually does what the cover letter says.
155
Explaining any "drive-by fixes" or roads not taken may also avoid queries
156
from the reviewer. All in all this should give faster and better reviews.
157
Sometimes writing the cover letter helps the submitter realize something
158
else they need to do. The size of the cover letter should be proportional
159
to the size and complexity of the patch.
162
Why make a local copy of bzr.dev?
163
---------------------------------
165
Making a local mirror of bzr.dev is not strictly necessary, but it means
167
- You can use that copy of bzr.dev as your main bzr executable, and keep it
168
up-to-date using ``bzr pull``.
169
- Certain operations are faster, and can be done when offline. For example:
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- ``bzr diff -r ancestor:...``
175
- When it's time to create your next branch, it's more convenient. When you
176
have further contributions to make, you should do them in their own branch::
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$ bzr branch bzr.dev additional_fixes
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$ cd additional_fixes # hack, hack, hack
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Understanding the Development Process
185
=====================================
187
The development team follows many practices including:
189
* a public roadmap and planning process in which anyone can participate
191
* time based milestones everyone can work towards and plan around
193
* extensive code review and feedback to contributors
195
* complete and rigorous test coverage on any code contributed
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* automated validation that all tests still pass before code is merged
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into the main code branch.
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The key tools we use to enable these practices are:
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* Launchpad - https://launchpad.net/
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* Bazaar - http://bazaar.canonical.com/
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* Patch Queue Manager - https://launchpad.net/pqm/
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For further information, see <http://wiki.bazaar.canonical.com/BzrDevelopment>.
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Preparing a Sandbox for Making Changes to Bazaar
214
================================================
216
Bazaar supports many ways of organising your work. See
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http://wiki.bazaar.canonical.com/SharedRepositoryLayouts for a summary of the
218
popular alternatives.
220
Of course, the best choice for you will depend on numerous factors:
221
the number of changes you may be making, the complexity of the changes, etc.
222
As a starting suggestion though:
224
* create a local copy of the main development branch (bzr.dev) by using
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bzr branch lp:bzr bzr.dev
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* keep your copy of bzr.dev pristine (by not developing in it) and keep
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it up to date (by using bzr pull)
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* create a new branch off your local bzr.dev copy for each issue
233
(bug or feature) you are working on.
235
This approach makes it easy to go back and make any required changes
236
after a code review. Resubmitting the change is then simple with no
237
risk of accidentally including edits related to other issues you may
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be working on. After the changes for an issue are accepted and merged,
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the associated branch can be deleted or archived as you wish.
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Navigating the Code Base
243
========================
245
.. Was at <http://wiki.bazaar.canonical.com/NewDeveloperIntroduction>
247
Some of the key files in this directory are:
250
The command you run to start Bazaar itself. This script is pretty
251
short and just does some checks then jumps into bzrlib.
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This file covers a brief introduction to Bazaar and lists some of its
258
Installs Bazaar system-wide or to your home directory. To perform
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development work on Bazaar it is not required to run this file - you
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can simply run the bzr command from the top level directory of your
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development copy. Note: That if you run setup.py this will create a
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'build' directory in your development branch. There's nothing wrong
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with this but don't be confused by it. The build process puts a copy
264
of the main code base into this build directory, along with some other
265
files. You don't need to go in here for anything discussed in this
269
Possibly the most exciting folder of all, bzrlib holds the main code
270
base. This is where you will go to edit python files and contribute to
274
Holds documentation on a whole range of things on Bazaar from the
275
origination of ideas within the project to information on Bazaar
276
features and use cases. Within this directory there is a subdirectory
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for each translation into a human language. All the documentation
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is in the ReStructuredText markup language.
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Documentation specifically targeted at Bazaar and plugin developers.
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(Including this document.)
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doc/en/release-notes/
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Detailed changes in each Bazaar release (there is one file by series:
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bzr-2.3.txt, bzr-2.4.txt, etc) that can affect users or plugin
292
High-level summaries of changes in each Bazaar release (there is one
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file by series: whats-new-in-2.3.txt, whats-new-in-2.4.txt, etc).
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Automatically-generated API reference information is available at
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<http://starship.python.net/crew/mwh/bzrlibapi/>.
299
See also the `Bazaar Architectural Overview
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<http://doc.bazaar.canonical.com/developers/overview.html>`_.
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We don't change APIs in stable branches: any supported symbol in a stable
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release of bzr must not be altered in any way that would result in
53
311
breaking existing code that uses it. That means that method names,
54
312
parameter ordering, parameter names, variable and attribute names etc must
55
313
not be changed without leaving a 'deprecated forwarder' behind. This even
59
317
way, you need to change its name as well. For instance, if I add an optional keyword
60
318
parameter to branch.commit - that's fine. On the other hand, if I add a
61
319
keyword parameter to branch.commit which is a *required* transaction
62
object, I should rename the API - i.e. to 'branch.commit_transaction'.
320
object, I should rename the API - i.e. to 'branch.commit_transaction'.
322
(Actually, that may break code that provides a new implementation of
323
``commit`` and doesn't expect to receive the parameter.)
64
325
When renaming such supported API's, be sure to leave a deprecated_method (or
65
326
_function or ...) behind which forwards to the new API. See the
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327
bzrlib.symbol_versioning module for decorators that take care of the
67
328
details for you - such as updating the docstring, and issuing a warning
68
when the old api is used.
329
when the old API is used.
70
331
For unsupported API's, it does not hurt to follow this discipline, but it's
71
332
not required. Minimally though, please try to rename things so that
72
333
callers will at least get an AttributeError rather than weird results.
75
Standard parameter types
76
------------------------
78
There are some common requirements in the library: some parameters need to be
79
unicode safe, some need byte strings, and so on. At the moment we have
80
only codified one specific pattern: Parameters that need to be unicode
81
should be checked via ``bzrlib.osutils.safe_unicode``. This will coerce the
82
input into unicode in a consistent fashion, allowing trivial strings to be
83
used for programmer convenience, but not performing unpredictably in the
84
presence of different locales.
336
Deprecation decorators
337
----------------------
339
``bzrlib.symbol_versioning`` provides decorators that can be attached to
340
methods, functions, and other interfaces to indicate that they should no
341
longer be used. For example::
343
@deprecated_method(deprecated_in((0, 1, 4)))
345
return self._new_foo()
347
To deprecate a static method you must call ``deprecated_function``
348
(**not** method), after the staticmethod call::
351
@deprecated_function(deprecated_in((0, 1, 4)))
352
def create_repository(base, shared=False, format=None):
354
When you deprecate an API, you should not just delete its tests, because
355
then we might introduce bugs in them. If the API is still present at all,
356
it should still work. The basic approach is to use
357
``TestCase.applyDeprecated`` which in one step checks that the API gives
358
the expected deprecation message, and also returns the real result from
359
the method, so that tests can keep running.
361
Deprecation warnings will be suppressed for final releases, but not for
362
development versions or release candidates, or when running ``bzr
363
selftest``. This gives developers information about whether their code is
364
using deprecated functions, but avoids confusing users about things they
116
400
I'm sure Canonical would do the same).
117
401
As such, Canonical has requested copyright assignments from all of the
118
402
major contributers.
120
404
3) If someone wants to add code and not attribute it to Canonical, there
121
405
is a specific list of files that are excluded from this check. And the
122
406
test failure indicates where that is, and how to update it.
124
408
4) If anyone feels that I changed a copyright statement incorrectly, just
125
409
let me know, and I'll be happy to correct it. Whenever you have large
126
410
mechanical changes like this, it is possible to make some mistakes.
128
412
Just to reiterate, this is a community project, and it is meant to stay
129
413
that way. Core bzr code is copyright Canonical for legal reasons, and
130
414
the tests are just there to help us maintain that.
136
If you change the behaviour of a command, please update its docstring
137
in bzrlib/commands.py. This is displayed by the 'bzr help' command.
142
If you make a user-visible change, please add a note to the NEWS file.
143
The description should be written to make sense to someone who's just
144
a user of bzr, not a developer: new functions or classes shouldn't be
145
mentioned, but new commands, changes in behaviour or fixed nontrivial
146
bugs should be listed. See the existing entries for an idea of what
149
Within each release, entries in the news file should have the most
150
user-visible changes first. So the order should be approximately:
152
* changes to existing behaviour - the highest priority because the
153
user's existing knowledge is incorrect
154
* new features - should be brought to their attention
155
* bug fixes - may be of interest if the bug was affecting them, and
156
should include the bug number if any
157
* major documentation changes
158
* changes to internal interfaces
160
People who made significant contributions to each change are listed in
161
parenthesis. This can include reporting bugs (particularly with good
162
details or reproduction recipes), submitting patches, etc.
167
Functions, methods, classes and modules should have docstrings
168
describing how they are used.
170
The first line of the docstring should be a self-contained sentence.
172
For the special case of Command classes, this acts as the user-visible
173
documentation shown by the help command.
175
The docstrings should be formatted as reStructuredText_ (like this
176
document), suitable for processing using the epydoc_ tool into HTML
179
.. _reStructuredText: http://docutils.sourceforge.net/rst.html
180
.. _epydoc: http://epydoc.sourceforge.net/
187
Please write PEP-8__ compliant code.
189
One often-missed requirement is that the first line of docstrings
190
should be a self-contained one-sentence summary.
192
__ http://www.python.org/peps/pep-0008.html
199
Functions, methods or members that are in some sense "private" are given
200
a leading underscore prefix. This is just a hint that code outside the
201
implementation should probably not use that interface.
203
We prefer class names to be concatenated capital words (``TestCase``)
204
and variables, methods and functions to be lowercase words joined by
205
underscores (``revision_id``, ``get_revision``).
207
For the purposes of naming some names are treated as single compound
208
words: "filename", "revno".
210
Consider naming classes as nouns and functions/methods as verbs.
212
Try to avoid using abbreviations in names, because there can be
213
inconsistency if other people use the full name.
219
``revision_id`` not ``rev_id`` or ``revid``
221
Functions that transform one thing to another should be named ``x_to_y``
222
(not ``x2y`` as occurs in some old code.)
228
Python destructors (``__del__``) work differently to those of other
229
languages. In particular, bear in mind that destructors may be called
230
immediately when the object apparently becomes unreferenced, or at some
231
later time, or possibly never at all. Therefore we have restrictions on
232
what can be done inside them.
234
0. Never use a __del__ method without asking Martin/Robert first.
236
1. Never rely on a ``__del__`` method running. If there is code that
237
must run, do it from a ``finally`` block instead.
239
2. Never ``import`` from inside a ``__del__`` method, or you may crash the
242
3. In some places we raise a warning from the destructor if the object
243
has not been cleaned up or closed. This is considered OK: the warning
244
may not catch every case but it's still useful sometimes.
250
In some places we have variables which point to callables that construct
251
new instances. That is to say, they can be used a lot like class objects,
252
but they shouldn't be *named* like classes:
254
> I think that things named FooBar should create instances of FooBar when
255
> called. Its plain confusing for them to do otherwise. When we have
256
> something that is going to be used as a class - that is, checked for via
257
> isinstance or other such idioms, them I would call it foo_class, so that
258
> it is clear that a callable is not sufficient. If it is only used as a
259
> factory, then yes, foo_factory is what I would use.
265
Several places in Bazaar use (or will use) a registry, which is a
266
mapping from names to objects or classes. The registry allows for
267
loading in registered code only when it's needed, and keeping
268
associated information such as a help string or description.
274
To make startup time faster, we use the ``bzrlib.lazy_import`` module to
275
delay importing modules until they are actually used. ``lazy_import`` uses
276
the same syntax as regular python imports. So to import a few modules in a
279
from bzrlib.lazy_import import lazy_import
280
lazy_import(globals(), """
289
revision as _mod_revision,
291
import bzrlib.transport
295
At this point, all of these exist as a ``ImportReplacer`` object, ready to
296
be imported once a member is accessed. Also, when importing a module into
297
the local namespace, which is likely to clash with variable names, it is
298
recommended to prefix it as ``_mod_<module>``. This makes it clean that
299
the variable is a module, and these object should be hidden anyway, since
300
they shouldn't be imported into other namespaces.
303
Modules versus Members
304
~~~~~~~~~~~~~~~~~~~~~~
306
While it is possible for ``lazy_import()`` to import members of a module
307
when using the ``from module import member`` syntax, it is recommended to
308
only use that syntax to load sub modules ``from module import submodule``.
309
This is because variables and classes can frequently be used without
310
needing a sub-member for example::
312
lazy_import(globals(), """
313
from module import MyClass
317
return isinstance(x, MyClass)
319
This will incorrectly fail, because ``MyClass`` is a ``ImportReplacer``
320
object, rather than the real class.
323
Passing to other variables
324
~~~~~~~~~~~~~~~~~~~~~~~~~~
326
It also is incorrect to assign ``ImportReplacer`` objects to other variables.
327
Because the replacer only knows about the original name, it is unable to
328
replace other variables. The ``ImportReplacer`` class will raise an
329
``IllegalUseOfScopeReplacer`` exception if it can figure out that this
330
happened. But it requires accessing a member more than once from the new
331
variable, so some bugs are not detected right away.
337
(The strategy described here is what we want to get to, but it's not
338
consistently followed in the code at the moment.)
340
bzrlib is intended to be a generically reusable library. It shouldn't
341
write messages to stdout or stderr, because some programs that use it
342
might want to display that information through a GUI or some other
345
We can distinguish two types of output from the library:
347
1. Structured data representing the progress or result of an
348
operation. For example, for a commit command this will be a list
349
of the modified files and the finally committed revision number
352
These should be exposed either through the return code or by calls
353
to a callback parameter.
355
A special case of this is progress indicators for long-lived
356
operations, where the caller should pass a ProgressBar object.
358
2. Unstructured log/debug messages, mostly for the benefit of the
359
developers or users trying to debug problems. This should always
360
be sent through ``bzrlib.trace`` and Python ``logging``, so that
361
it can be redirected by the client.
363
The distinction between the two is a bit subjective, but in general if
364
there is any chance that a library would want to see something as
365
structured data, we should make it so.
367
The policy about how output is presented in the text-mode client
368
should be only in the command-line tool.
374
In general tests should be placed in a file named test_FOO.py where
375
FOO is the logical thing under test. That file should be placed in the
376
tests subdirectory under the package being tested.
378
For example, tests for merge3 in bzrlib belong in bzrlib/tests/test_merge3.py.
379
See bzrlib/selftest/test_sampler.py for a template test script.
381
Tests can be written for the UI or for individual areas of the library.
382
Choose whichever is appropriate: if adding a new command, or a new command
383
option, then you should be writing a UI test. If you are both adding UI
384
functionality and library functionality, you will want to write tests for
385
both the UI and the core behaviours. We call UI tests 'blackbox' tests
386
and they are found in ``bzrlib/tests/blackbox/*.py``.
388
When writing blackbox tests please honour the following conventions:
390
1. Place the tests for the command 'name' in
391
bzrlib/tests/blackbox/test_name.py. This makes it easy for developers
392
to locate the test script for a faulty command.
394
2. Use the 'self.run_bzr("name")' utility function to invoke the command
395
rather than running bzr in a subprocess or invoking the
396
cmd_object.run() method directly. This is a lot faster than
397
subprocesses and generates the same logging output as running it in a
398
subprocess (which invoking the method directly does not).
400
3. Only test the one command in a single test script. Use the bzrlib
401
library when setting up tests and when evaluating the side-effects of
402
the command. We do this so that the library api has continual pressure
403
on it to be as functional as the command line in a simple manner, and
404
to isolate knock-on effects throughout the blackbox test suite when a
405
command changes its name or signature. Ideally only the tests for a
406
given command are affected when a given command is changed.
408
4. If you have a test which does actually require running bzr in a
409
subprocess you can use ``run_bzr_subprocess``. By default the spawned
410
process will not load plugins unless ``--allow-plugins`` is supplied.
416
We make selective use of doctests__. In general they should provide
417
*examples* within the API documentation which can incidentally be tested. We
418
don't try to test every important case using doctests -- regular Python
419
tests are generally a better solution.
421
Most of these are in ``bzrlib/doc/api``. More additions are welcome.
423
__ http://docs.python.org/lib/module-doctest.html
428
Currently, bzr selftest is used to invoke tests.
429
You can provide a pattern argument to run a subset. For example,
430
to run just the blackbox tests, run::
432
./bzr selftest -v blackbox
434
To skip a particular test (or set of tests), you need to use a negative
437
./bzr selftest '^(?!.*blackbox)'
440
Errors and exceptions
441
=====================
443
Errors are handled through Python exceptions.
445
We broadly classify errors as either being either internal or not,
446
depending on whether ``user_error`` is set or not. If we think it's our
447
fault, we show a backtrace, an invitation to report the bug, and possibly
448
other details. This is the default for errors that aren't specifically
449
recognized as being caused by a user error. Otherwise we show a briefer
450
message, unless -Derror was given.
452
Many errors originate as "environmental errors" which are raised by Python
453
or builtin libraries -- for example IOError. These are treated as being
454
our fault, unless they're caught in a particular tight scope where we know
455
that they indicate a user errors. For example if the repository format
456
is not found, the user probably gave the wrong path or URL. But if one of
457
the files inside the repository is not found, then it's our fault --
458
either there's a bug in bzr, or something complicated has gone wrong in
459
the environment that means one internal file was deleted.
461
Many errors are defined in ``bzrlib/errors.py`` but it's OK for new errors
462
to be added near the place where they are used.
464
Exceptions are formatted for the user by conversion to a string
465
(eventually calling their ``__str__`` method.) As a convenience the
466
``._fmt`` member can be used as a template which will be mapped to the
467
error's instance dict.
469
New exception classes should be defined when callers might want to catch
470
that exception specifically, or when it needs a substantially different
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Exception strings should start with a capital letter and should not have a
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final fullstop. If long, they may contain newlines to break the text.
423
Bazaar has a few facilities to help debug problems by going into pdb_, the
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.. _pdb: http://docs.python.org/lib/debugger-commands.html
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If the ``BZR_PDB`` environment variable is set
429
then bzr will go into pdb post-mortem mode when an unhandled exception
432
If you send a SIGQUIT or SIGBREAK signal to bzr then it will drop into the
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debugger immediately. SIGQUIT can be generated by pressing Ctrl-\\ on
434
Unix. SIGBREAK is generated with Ctrl-Pause on Windows (some laptops have
435
this as Fn-Pause). You can continue execution by typing ``c``. This can
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be disabled if necessary by setting the environment variable
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``BZR_SIGQUIT_PDB=0``.
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Bazaar accepts some global options starting with ``-D`` such as
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``-Dhpss``. These set a value in `bzrlib.debug.debug_flags`, and
445
typically cause more information to be written to the trace file. Most
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`mutter` calls should be guarded by a check of those flags so that we
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don't write out too much information if it's not needed.
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Debug flags may have effects other than just emitting trace messages.
451
Run ``bzr help global-options`` to see them all.
453
These flags may also be set as a comma-separated list in the
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``debug_flags`` option in e.g. ``~/.bazaar/bazaar.conf``. (Note that it
455
must be in this global file, not in the branch or location configuration,
456
because it's currently only loaded at startup time.) For instance you may
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want to always record hpss traces and to see full error tracebacks::
459
debug_flags = hpss, error
583
517
Because Transports work in URLs (as defined earlier), printing the raw URL
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518
to the user is usually less than optimal. Characters outside the standard
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519
set are printed as escapes, rather than the real character, and local
586
paths would be printed as ``file://`` urls. The function
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paths would be printed as ``file://`` URLs. The function
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521
``unescape_for_display`` attempts to unescape a URL, such that anything
588
522
that cannot be printed in the current encoding stays an escaped URL, but
589
523
valid characters are generated where possible.
595
If you'd like to propose a change, please post to the
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bazaar@lists.canonical.com list with a patch, bzr changeset, or link to a
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branch. Please put '[patch]' in the subject so we can pick them out, and
598
include some text explaining the change. Remember to put an update to the NEWS
599
file in your diff, if it makes any changes visible to users or plugin
600
developers. Please include a diff against mainline if you're giving a link to
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Please indicate if you think the code is ready to merge, or if it's just a
604
draft or for discussion. If you want comments from many developers rather than
605
to be merged, you can put '[rfc]' in the subject lines.
607
Anyone is welcome to review code. There are broadly three gates for
610
* Doesn't reduce test coverage: if it adds new methods or commands,
611
there should be tests for them. There is a good test framework
612
and plenty of examples to crib from, but if you are having trouble
613
working out how to test something feel free to post a draft patch
616
* Doesn't reduce design clarity, such as by entangling objects
617
we're trying to separate. This is mostly something the more
618
experienced reviewers need to help check.
620
* Improves bugs, features, speed, or code simplicity.
622
Code that goes in should pass all three.
624
If you read a patch please reply and say so. We can use a numeric scale
625
of -1, -0, +0, +1, meaning respectively "really don't want it in current
626
form", "somewhat uncomfortable", "ok with me", and "please put it in".
627
Anyone can "vote". (It's not really voting, just a terse expression.)
629
If something gets say two +1 votes from core reviewers, and no
630
vetos, then it's OK to come in. Any of the core developers can bring it
631
into their integration branch, which I'll merge regularly. (If you do
632
so, please reply and say so.)
635
Making installers for OS Windows
529
We write some extensions in C using pyrex. We design these to work in
532
* User with no C compiler
533
* User with C compiler
536
The recommended way to install bzr is to have a C compiler so that the
537
extensions can be built, but if no C compiler is present, the pure python
538
versions we supply will work, though more slowly.
540
For developers we recommend that pyrex be installed, so that the C
541
extensions can be changed if needed.
543
For the C extensions, the extension module should always match the
544
original python one in all respects (modulo speed). This should be
545
maintained over time.
547
To create an extension, add rules to setup.py for building it with pyrex,
548
and with distutils. Now start with an empty .pyx file. At the top add
549
"include 'yourmodule.py'". This will import the contents of foo.py into this
550
file at build time - remember that only one module will be loaded at
551
runtime. Now you can subclass classes, or replace functions, and only your
552
changes need to be present in the .pyx file.
554
Note that pyrex does not support all 2.4 programming idioms, so some
555
syntax changes may be required. I.e.
557
- 'from foo import (bar, gam)' needs to change to not use the brackets.
558
- 'import foo.bar as bar' needs to be 'import foo.bar; bar = foo.bar'
560
If the changes are too dramatic, consider
561
maintaining the python code twice - once in the .pyx, and once in the .py,
562
and no longer including the .py file.
565
Making Installers for OS Windows
636
566
================================
637
567
To build a win32 installer, see the instructions on the wiki page:
638
http://bazaar-vcs.org/BzrWin32Installer
641
:: vim: ft=rst tw=74 ai
568
http://wiki.bazaar.canonical.com/BzrWin32Installer
576
What is a Core Developer?
577
-------------------------
579
While everyone in the Bazaar community is welcome and encouraged to
580
propose and submit changes, a smaller team is reponsible for pulling those
581
changes together into a cohesive whole. In addition to the general developer
582
stuff covered above, "core" developers have responsibility for:
586
* managing releases (see `Releasing Bazaar <http://doc.bazaar.canonical.com/developers/releasing.html>`_)
589
Removing barriers to community participation is a key reason for adopting
590
distributed VCS technology. While DVCS removes many technical barriers,
591
a small number of social barriers are often necessary instead.
592
By documenting how the above things are done, we hope to
593
encourage more people to participate in these activities, keeping the
594
differences between core and non-core contributors to a minimum.
597
Communicating and Coordinating
598
------------------------------
600
While it has many advantages, one of the challenges of distributed
601
development is keeping everyone else aware of what you're working on.
602
There are numerous ways to do this:
604
#. Assign bugs to yourself in Launchpad
605
#. Mention it on the mailing list
608
As well as the email notifcations that occur when merge requests are sent
609
and reviewed, you can keep others informed of where you're spending your
610
energy by emailing the **bazaar-commits** list implicitly. To do this,
611
install and configure the Email plugin. One way to do this is add these
612
configuration settings to your central configuration file (e.g.
613
``~/.bazaar/bazaar.conf``)::
616
email = Joe Smith <joe.smith@internode.on.net>
617
smtp_server = mail.internode.on.net:25
619
Then add these lines for the relevant branches in ``locations.conf``::
621
post_commit_to = bazaar-commits@lists.canonical.com
622
post_commit_mailer = smtplib
624
While attending a sprint, RobertCollins' Dbus plugin is useful for the
625
same reason. See the documentation within the plugin for information on
626
how to set it up and configure it.
637
Keeping on top of bugs reported is an important part of ongoing release
638
planning. Everyone in the community is welcome and encouraged to raise
639
bugs, confirm bugs raised by others, and nominate a priority. Practically
640
though, a good percentage of bug triage is often done by the core
641
developers, partially because of their depth of product knowledge.
643
With respect to bug triage, core developers are encouraged to play an
644
active role with particular attention to the following tasks:
646
* keeping the number of unconfirmed bugs low
647
* ensuring the priorities are generally right (everything as critical - or
648
medium - is meaningless)
649
* looking out for regressions and turning those around sooner rather than later.
652
As well as prioritizing bugs and nominating them against a
653
target milestone, Launchpad lets core developers offer to mentor others in
added
removed
doc/developers/HACKING.txt
