73
73
Bazaar Development in a Nutshell
74
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
92
$ bzr branch lp:bzr bzr.dev
94
Now make your own branch::
96
$ bzr branch bzr.dev 123456-my-bugfix
98
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
120
$ bzr push lp:~<your_lp_username>/bzr/meaningful_name_here
122
After you have pushed your branch, you will need to propose it for merging to
123
the Bazaar trunk. Go to
124
<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:
172
- ``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::
179
$ bzr branch bzr.dev additional_fixes
180
$ cd additional_fixes # hack, hack, hack
76
Looking for a 10 minute introduction to submitting a change?
77
See http://bazaar-vcs.org/BzrGivingBack.
79
TODO: Merge that Wiki page into this document.
184
82
Understanding the Development Process
274
178
Holds documentation on a whole range of things on Bazaar from the
275
179
origination of ideas within the project to information on Bazaar
276
180
features and use cases. Within this directory there is a subdirectory
277
for each translation into a human language. All the documentation
181
for each translation into a human language. All the documentation
278
182
is in the ReStructuredText markup language.
281
Documentation specifically targeted at Bazaar and plugin developers.
185
Documentation specifically targetted at Bazaar and plugin developers.
282
186
(Including this document.)
284
doc/en/release-notes/
286
Detailed changes in each Bazaar release (there is one file by series:
287
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
293
file by series: whats-new-in-2.3.txt, whats-new-in-2.4.txt, etc).
296
Automatically-generated API reference information is available at
297
<http://starship.python.net/crew/mwh/bzrlibapi/>.
299
See also the `Bazaar Architectural Overview
300
<http://doc.bazaar.canonical.com/developers/overview.html>`_.
190
Automatically-generated API reference information is available at
191
<http://starship.python.net/crew/mwh/bzrlibapi/>.
192
(There is an experimental editable version at
193
<http://starship.python.net/crew/mwh/bzrlibapi-oe/>.)
195
See also the `Bazaar Architectural Overview <../../developers/overview.html>`_.
198
The Code Review Process
199
#######################
201
All code changes coming in to Bazaar are reviewed by someone else.
202
Normally changes by core contributors are reviewed by one other core
203
developer, and changes from other people are reviewed by two core
204
developers. Use intelligent discretion if the patch is trivial.
206
Good reviews do take time. They also regularly require a solid
207
understanding of the overall code base. In practice, this means a small
208
number of people often have a large review burden - with knowledge comes
209
responsibility. No one like their merge requests sitting in a queue going
210
nowhere, so reviewing sooner rather than later is strongly encouraged.
214
Sending patches for review
215
==========================
217
If you'd like to propose a change, please post to the
218
bazaar@lists.canonical.com list with a bundle, patch, or link to a
219
branch. Put ``[PATCH]`` or ``[MERGE]`` in the subject so Bundle Buggy
220
can pick it out, and explain the change in the email message text.
221
Remember to update the NEWS file as part of your change if it makes any
222
changes visible to users or plugin developers. Please include a diff
223
against mainline if you're giving a link to a branch.
225
You can generate a merge request like this::
227
bzr send -o bug-1234.diff
229
A ``.diff`` extension is recommended instead of .bundle as many mail clients
230
will send the latter as a binary file.
232
``bzr send`` can also send mail directly if you prefer; see the help.
234
Please do **NOT** put [PATCH] or [MERGE] in the subject line if you don't
235
want it to be merged. If you want comments from developers rather than
236
to be merged, you can put ``[RFC]`` in the subject line.
238
If this change addresses a bug, please put the bug number in the subject
239
line too, in the form ``[#1]`` so that Bundle Buggy can recognize it.
241
If the change is intended for a particular release mark that in the
242
subject too, e.g. ``[1.6]``.
248
Please put a "cover letter" on your merge request explaining:
250
* the reason **why** you're making this change
252
* **how** this change acheives this purpose
254
* anything else you may have fixed in passing
256
* anything significant that you thought of doing, such as a more
257
extensive fix or a different approach, but didn't or couldn't do now
259
A good cover letter makes reviewers' lives easier because they can decide
260
from the letter whether they agree with the purpose and approach, and then
261
assess whether the patch actually does what the cover letter says.
262
Explaining any "drive-by fixes" or roads not taken may also avoid queries
263
from the reviewer. All in all this should give faster and better reviews.
264
Sometimes writing the cover letter helps the submitter realize something
265
else they need to do. The size of the cover letter should be proportional
266
to the size and complexity of the patch.
269
Reviewing proposed changes
270
==========================
272
Anyone is welcome to review code, and reply to the thread with their
275
The simplest way to review a proposed change is to just read the patch on
276
the list or in Bundle Buggy. For more complex changes it may be useful
277
to make a new working tree or branch from trunk, and merge the proposed
278
change into it, so you can experiment with the code or look at a wider
281
There are three main requirements for code to get in:
283
* Doesn't reduce test coverage: if it adds new methods or commands,
284
there should be tests for them. There is a good test framework
285
and plenty of examples to crib from, but if you are having trouble
286
working out how to test something feel free to post a draft patch
289
* Doesn't reduce design clarity, such as by entangling objects
290
we're trying to separate. This is mostly something the more
291
experienced reviewers need to help check.
293
* Improves bugs, features, speed, or code simplicity.
295
Code that goes in should not degrade any of these aspects. Patches are
296
welcome that only cleanup the code without changing the external
297
behaviour. The core developers take care to keep the code quality high
298
and understandable while recognising that perfect is sometimes the enemy
301
It is easy for reviews to make people notice other things which should be
302
fixed but those things should not hold up the original fix being accepted.
303
New things can easily be recorded in the Bug Tracker instead.
305
It's normally much easier to review several smaller patches than one large
306
one. You might want to use ``bzr-loom`` to maintain threads of related
307
work, or submit a preparatory patch that will make your "real" change
311
Checklist for reviewers
312
=======================
314
* Do you understand what the code's doing and why?
316
* Will it perform reasonably for large inputs, both in memory size and
317
run time? Are there some scenarios where performance should be
320
* Is it tested, and are the tests at the right level? Are there both
321
blackbox (command-line level) and API-oriented tests?
323
* If this change will be visible to end users or API users, is it
324
appropriately documented in NEWS?
326
* Does it meet the coding standards below?
328
* If it changes the user-visible behaviour, does it update the help
329
strings and user documentation?
331
* If it adds a new major concept or standard practice, does it update the
332
developer documentation?
334
* (your ideas here...)
337
Bundle Buggy and review outcomes
338
================================
340
Anyone can "vote" on the mailing list by expressing an opinion. Core
341
developers can also vote using Bundle Buggy. Here are the voting codes and
344
:approve: Reviewer wants this submission merged.
345
:tweak: Reviewer wants this submission merged with small changes. (No
347
:abstain: Reviewer does not intend to vote on this patch.
348
:resubmit: Please make changes and resubmit for review.
349
:reject: Reviewer doesn't want this kind of change merged.
350
:comment: Not really a vote. Reviewer just wants to comment, for now.
352
If a change gets two approvals from core reviewers, and no rejections,
353
then it's OK to come in. Any of the core developers can bring it into the
354
bzr.dev trunk and backport it to maintenance branches if required. The
355
Release Manager will merge the change into the branch for a pending
356
release, if any. As a guideline, core developers usually merge their own
357
changes and volunteer to merge other contributions if they were the second
358
reviewer to agree to a change.
360
To track the progress of proposed changes, use Bundle Buggy. See
361
http://bundlebuggy.aaronbentley.com/help for a link to all the
362
outstanding merge requests together with an explanation of the columns.
363
Bundle Buggy will also mail you a link to track just your change.
365
Coding Style Guidelines
366
#######################
371
``hasattr`` should not be used because it swallows exceptions including
372
``KeyboardInterrupt``. Instead, say something like ::
374
if getattr(thing, 'name', None) is None
380
Please write PEP-8__ compliant code.
382
__ http://www.python.org/peps/pep-0008.html
384
One often-missed requirement is that the first line of docstrings
385
should be a self-contained one-sentence summary.
387
We use 4 space indents for blocks, and never use tab characters. (In vim,
390
Lines should be no more than 79 characters if at all possible.
391
Lines that continue a long statement may be indented in either of
394
within the parenthesis or other character that opens the block, e.g.::
400
or indented by four spaces::
406
The first is considered clearer by some people; however it can be a bit
407
harder to maintain (e.g. when the method name changes), and it does not
408
work well if the relevant parenthesis is already far to the right. Avoid
411
self.legbone.kneebone.shinbone.toebone.shake_it(one,
417
self.legbone.kneebone.shinbone.toebone.shake_it(one,
423
self.legbone.kneebone.shinbone.toebone.shake_it(
426
For long lists, we like to add a trailing comma and put the closing
427
character on the following line. This makes it easier to add new items in
430
from bzrlib.goo import (
436
There should be spaces between function paramaters, but not between the
437
keyword name and the value::
439
call(1, 3, cheese=quark)
443
;(defface my-invalid-face
444
; '((t (:background "Red" :underline t)))
445
; "Face used to highlight invalid constructs or other uglyties"
448
(defun my-python-mode-hook ()
449
;; setup preferred indentation style.
450
(setq fill-column 79)
451
(setq indent-tabs-mode nil) ; no tabs, never, I will not repeat
452
; (font-lock-add-keywords 'python-mode
453
; '(("^\\s *\t" . 'my-invalid-face) ; Leading tabs
454
; ("[ \t]+$" . 'my-invalid-face) ; Trailing spaces
455
; ("^[ \t]+$" . 'my-invalid-face)); Spaces only
459
(add-hook 'python-mode-hook 'my-python-mode-hook)
461
The lines beginning with ';' are comments. They can be activated
462
if one want to have a strong notice of some tab/space usage
469
* Imports should be done at the top-level of the file, unless there is
470
a strong reason to have them lazily loaded when a particular
471
function runs. Import statements have a cost, so try to make sure
472
they don't run inside hot functions.
474
* Module names should always be given fully-qualified,
475
i.e. ``bzrlib.hashcache`` not just ``hashcache``.
481
Functions, methods or members that are "private" to bzrlib are given
482
a leading underscore prefix. Names without a leading underscore are
483
public not just across modules but to programmers using bzrlib as an
484
API. As a consequence, a leading underscore is appropriate for names
485
exposed across modules but that are not to be exposed to bzrlib API
488
We prefer class names to be concatenated capital words (``TestCase``)
489
and variables, methods and functions to be lowercase words joined by
490
underscores (``revision_id``, ``get_revision``).
492
For the purposes of naming some names are treated as single compound
493
words: "filename", "revno".
495
Consider naming classes as nouns and functions/methods as verbs.
497
Try to avoid using abbreviations in names, because there can be
498
inconsistency if other people use the full name.
504
``revision_id`` not ``rev_id`` or ``revid``
506
Functions that transform one thing to another should be named ``x_to_y``
507
(not ``x2y`` as occurs in some old code.)
513
Python destructors (``__del__``) work differently to those of other
514
languages. In particular, bear in mind that destructors may be called
515
immediately when the object apparently becomes unreferenced, or at some
516
later time, or possibly never at all. Therefore we have restrictions on
517
what can be done inside them.
519
0. If you think you need to use a ``__del__`` method ask another
520
developer for alternatives. If you do need to use one, explain
523
1. Never rely on a ``__del__`` method running. If there is code that
524
must run, do it from a ``finally`` block instead.
526
2. Never ``import`` from inside a ``__del__`` method, or you may crash the
529
3. In some places we raise a warning from the destructor if the object
530
has not been cleaned up or closed. This is considered OK: the warning
531
may not catch every case but it's still useful sometimes.
537
In some places we have variables which point to callables that construct
538
new instances. That is to say, they can be used a lot like class objects,
539
but they shouldn't be *named* like classes:
541
> I think that things named FooBar should create instances of FooBar when
542
> called. Its plain confusing for them to do otherwise. When we have
543
> something that is going to be used as a class - that is, checked for via
544
> isinstance or other such idioms, them I would call it foo_class, so that
545
> it is clear that a callable is not sufficient. If it is only used as a
546
> factory, then yes, foo_factory is what I would use.
552
Several places in Bazaar use (or will use) a registry, which is a
553
mapping from names to objects or classes. The registry allows for
554
loading in registered code only when it's needed, and keeping
555
associated information such as a help string or description.
558
InterObject and multiple dispatch
559
=================================
561
The ``InterObject`` provides for two-way `multiple dispatch`__: matching
562
up for example a source and destination repository to find the right way
563
to transfer data between them.
565
.. __: http://en.wikipedia.org/wiki/Multiple_dispatch
567
There is a subclass ``InterObject`` classes for each type of object that is
568
dispatched this way, e.g. ``InterRepository``. Calling ``.get()`` on this
569
class will return an ``InterObject`` instance providing the best match for
570
those parameters, and this instance then has methods for operations
573
inter = InterRepository.get(source_repo, target_repo)
574
inter.fetch(revision_id)
576
``InterRepository`` also acts as a registry-like object for its
577
subclasses, and they can be added through ``.register_optimizer``. The
578
right one to run is selected by asking each class, in reverse order of
579
registration, whether it ``.is_compatible`` with the relevant objects.
584
To make startup time faster, we use the ``bzrlib.lazy_import`` module to
585
delay importing modules until they are actually used. ``lazy_import`` uses
586
the same syntax as regular python imports. So to import a few modules in a
589
from bzrlib.lazy_import import lazy_import
590
lazy_import(globals(), """
599
revision as _mod_revision,
601
import bzrlib.transport
605
At this point, all of these exist as a ``ImportReplacer`` object, ready to
606
be imported once a member is accessed. Also, when importing a module into
607
the local namespace, which is likely to clash with variable names, it is
608
recommended to prefix it as ``_mod_<module>``. This makes it clearer that
609
the variable is a module, and these object should be hidden anyway, since
610
they shouldn't be imported into other namespaces.
612
While it is possible for ``lazy_import()`` to import members of a module
613
when using the ``from module import member`` syntax, it is recommended to
614
only use that syntax to load sub modules ``from module import submodule``.
615
This is because variables and classes can frequently be used without
616
needing a sub-member for example::
618
lazy_import(globals(), """
619
from module import MyClass
623
return isinstance(x, MyClass)
625
This will incorrectly fail, because ``MyClass`` is a ``ImportReplacer``
626
object, rather than the real class.
628
It also is incorrect to assign ``ImportReplacer`` objects to other variables.
629
Because the replacer only knows about the original name, it is unable to
630
replace other variables. The ``ImportReplacer`` class will raise an
631
``IllegalUseOfScopeReplacer`` exception if it can figure out that this
632
happened. But it requires accessing a member more than once from the new
633
variable, so some bugs are not detected right away.
639
The null revision is the ancestor of all revisions. Its revno is 0, its
640
revision-id is ``null:``, and its tree is the empty tree. When referring
641
to the null revision, please use ``bzrlib.revision.NULL_REVISION``. Old
642
code sometimes uses ``None`` for the null revision, but this practice is
646
Object string representations
647
=============================
649
Python prints objects using their ``__repr__`` method when they are
650
written to logs, exception tracebacks, or the debugger. We want
651
objects to have useful representations to help in determining what went
654
If you add a new class you should generally add a ``__repr__`` method
655
unless there is an adequate method in a parent class. There should be a
658
Representations should typically look like Python constructor syntax, but
659
they don't need to include every value in the object and they don't need
660
to be able to actually execute. They're to be read by humans, not
661
machines. Don't hardcode the classname in the format, so that we get the
662
correct value if the method is inherited by a subclass. If you're
663
printing attributes of the object, including strings, you should normally
664
use ``%r`` syntax (to call their repr in turn).
666
Try to avoid the representation becoming more than one or two lines long.
667
(But balance this against including useful information, and simplicity of
670
Because repr methods are often called when something has already gone
671
wrong, they should be written somewhat more defensively than most code.
672
The object may be half-initialized or in some other way in an illegal
673
state. The repr method shouldn't raise an exception, or it may hide the
674
(probably more useful) underlying exception.
679
return '%s(%r)' % (self.__class__.__name__,
686
A bare ``except`` statement will catch all exceptions, including ones that
687
really should terminate the program such as ``MemoryError`` and
688
``KeyboardInterrupt``. They should rarely be used unless the exception is
689
later re-raised. Even then, think about whether catching just
690
``Exception`` (which excludes system errors in Python2.5 and later) would
697
All code should be exercised by the test suite. See `Guide to Testing
698
Bazaar <testing.html>`_ for detailed information about writing tests.
766
Processing Command Lines
767
------------------------
769
bzrlib has a standard framework for parsing command lines and calling
770
processing routines associated with various commands. See builtins.py
771
for numerous examples.
774
Standard Parameter Types
775
------------------------
777
There are some common requirements in the library: some parameters need to be
778
unicode safe, some need byte strings, and so on. At the moment we have
779
only codified one specific pattern: Parameters that need to be unicode
780
should be checked via ``bzrlib.osutils.safe_unicode``. This will coerce the
781
input into unicode in a consistent fashion, allowing trivial strings to be
782
used for programmer convenience, but not performing unpredictably in the
783
presence of different locales.
789
(The strategy described here is what we want to get to, but it's not
790
consistently followed in the code at the moment.)
792
bzrlib is intended to be a generically reusable library. It shouldn't
793
write messages to stdout or stderr, because some programs that use it
794
might want to display that information through a GUI or some other
797
We can distinguish two types of output from the library:
799
1. Structured data representing the progress or result of an
800
operation. For example, for a commit command this will be a list
801
of the modified files and the finally committed revision number
804
These should be exposed either through the return code or by calls
805
to a callback parameter.
807
A special case of this is progress indicators for long-lived
808
operations, where the caller should pass a ProgressBar object.
810
2. Unstructured log/debug messages, mostly for the benefit of the
811
developers or users trying to debug problems. This should always
812
be sent through ``bzrlib.trace`` and Python ``logging``, so that
813
it can be redirected by the client.
815
The distinction between the two is a bit subjective, but in general if
816
there is any chance that a library would want to see something as
817
structured data, we should make it so.
819
The policy about how output is presented in the text-mode client
820
should be only in the command-line tool.
827
Bazaar has online help for various topics through ``bzr help COMMAND`` or
828
equivalently ``bzr command -h``. We also have help on command options,
829
and on other help topics. (See ``help_topics.py``.)
831
As for python docstrings, the first paragraph should be a single-sentence
832
synopsis of the command.
834
The help for options should be one or more proper sentences, starting with
835
a capital letter and finishing with a full stop (period).
837
All help messages and documentation should have two spaces between
841
Handling Errors and Exceptions
842
==============================
844
Commands should return non-zero when they encounter circumstances that
845
the user should really pay attention to - which includes trivial shell
848
Recommended values are:
851
1. Conflicts in merge-like operations, or changes are present in
852
diff-like operations.
853
2. Unrepresentable diff changes (i.e. binary files that we cannot show
855
3. An error or exception has occurred.
856
4. An internal error occurred (one that shows a traceback.)
858
Errors are handled through Python exceptions. Exceptions should be defined
859
inside bzrlib.errors, so that we can see the whole tree at a glance.
861
We broadly classify errors as either being either internal or not,
862
depending on whether ``internal_error`` is set or not. If we think it's our
863
fault, we show a backtrace, an invitation to report the bug, and possibly
864
other details. This is the default for errors that aren't specifically
865
recognized as being caused by a user error. Otherwise we show a briefer
866
message, unless -Derror was given.
868
Many errors originate as "environmental errors" which are raised by Python
869
or builtin libraries -- for example IOError. These are treated as being
870
our fault, unless they're caught in a particular tight scope where we know
871
that they indicate a user errors. For example if the repository format
872
is not found, the user probably gave the wrong path or URL. But if one of
873
the files inside the repository is not found, then it's our fault --
874
either there's a bug in bzr, or something complicated has gone wrong in
875
the environment that means one internal file was deleted.
877
Many errors are defined in ``bzrlib/errors.py`` but it's OK for new errors
878
to be added near the place where they are used.
880
Exceptions are formatted for the user by conversion to a string
881
(eventually calling their ``__str__`` method.) As a convenience the
882
``._fmt`` member can be used as a template which will be mapped to the
883
error's instance dict.
885
New exception classes should be defined when callers might want to catch
886
that exception specifically, or when it needs a substantially different
889
Exception strings should start with a capital letter and should not have a
890
final fullstop. If long, they may contain newlines to break the text.
896
Do not use the Python ``assert`` statement, either in tests or elsewhere.
897
A source test checks that it is not used. It is ok to explicitly raise
902
* It makes the behaviour vary depending on whether bzr is run with -O
903
or not, therefore giving a chance for bugs that occur in one case or
904
the other, several of which have already occurred: assertions with
905
side effects, code which can't continue unless the assertion passes,
906
cases where we should give the user a proper message rather than an
908
* It's not that much shorter than an explicit if/raise.
909
* It tends to lead to fuzzy thinking about whether the check is
910
actually needed or not, and whether it's an internal error or not
911
* It tends to cause look-before-you-leap patterns.
912
* It's unsafe if the check is needed to protect the integrity of the
914
* It tends to give poor messages since the developer can get by with
915
no explanatory text at all.
916
* We can't rely on people always running with -O in normal use, so we
917
can't use it for tests that are actually expensive.
918
* Expensive checks that help developers are better turned on from the
919
test suite or a -D flag.
920
* If used instead of ``self.assert*()`` in tests it makes them falsely pass with -O.
926
When you change bzrlib, please update the relevant documentation for the
927
change you made: Changes to commands should update their help, and
928
possibly end user tutorials; changes to the core library should be
929
reflected in API documentation.
934
If you make a user-visible change, please add a note to the NEWS file.
935
The description should be written to make sense to someone who's just
936
a user of bzr, not a developer: new functions or classes shouldn't be
937
mentioned, but new commands, changes in behaviour or fixed nontrivial
938
bugs should be listed. See the existing entries for an idea of what
941
Within each release, entries in the news file should have the most
942
user-visible changes first. So the order should be approximately:
944
* changes to existing behaviour - the highest priority because the
945
user's existing knowledge is incorrect
946
* new features - should be brought to their attention
947
* bug fixes - may be of interest if the bug was affecting them, and
948
should include the bug number if any
949
* major documentation changes
950
* changes to internal interfaces
952
People who made significant contributions to each change are listed in
953
parenthesis. This can include reporting bugs (particularly with good
954
details or reproduction recipes), submitting patches, etc.
959
The docstring of a command is used by ``bzr help`` to generate help output
960
for the command. The list 'takes_options' attribute on a command is used by
961
``bzr help`` to document the options for the command - the command
962
docstring does not need to document them. Finally, the '_see_also'
963
attribute on a command can be used to reference other related help topics.
968
Functions, methods, classes and modules should have docstrings
969
describing how they are used.
971
The first line of the docstring should be a self-contained sentence.
973
For the special case of Command classes, this acts as the user-visible
974
documentation shown by the help command.
976
The docstrings should be formatted as reStructuredText_ (like this
977
document), suitable for processing using the epydoc_ tool into HTML
980
.. _reStructuredText: http://docutils.sourceforge.net/rst.html
981
.. _epydoc: http://epydoc.sourceforge.net/
368
984
General Guidelines
369
985
==================
626
1231
how to set it up and configure it.
1240
Of the many workflows supported by Bazaar, the one adopted for Bazaar
1241
development itself is known as "Decentralized with automatic gatekeeper".
1242
To repeat the explanation of this given on
1243
http://bazaar-vcs.org/Workflows:
1246
In this workflow, each developer has their own branch or
1247
branches, plus read-only access to the mainline. A software gatekeeper
1248
(e.g. PQM) has commit rights to the main branch. When a developer wants
1249
their work merged, they request the gatekeeper to merge it. The gatekeeper
1250
does a merge, a compile, and runs the test suite. If the code passes, it
1251
is merged into the mainline.
1253
In a nutshell, here's the overall submission process:
1255
#. get your work ready (including review except for trivial changes)
1256
#. push to a public location
1257
#. ask PQM to merge from that location
1260
At present, PQM always takes the changes to merge from a branch
1261
at a URL that can be read by it. For Bazaar, that means a public,
1262
typically http, URL.
1264
As a result, the following things are needed to use PQM for submissions:
1266
#. A publicly available web server
1267
#. Your OpenPGP key registered with PQM (contact RobertCollins for this)
1268
#. The PQM plugin installed and configured (not strictly required but
1269
highly recommended).
1272
Selecting a Public Branch Location
1273
----------------------------------
1275
If you don't have your own web server running, branches can always be
1276
pushed to Launchpad. Here's the process for doing that:
1278
Depending on your location throughout the world and the size of your
1279
repository though, it is often quicker to use an alternative public
1280
location to Launchpad, particularly if you can set up your own repo and
1281
push into that. By using an existing repo, push only needs to send the
1282
changes, instead of the complete repository every time. Note that it is
1283
easy to register branches in other locations with Launchpad so no benefits
1284
are lost by going this way.
1287
For Canonical staff, http://people.ubuntu.com/~<user>/ is one
1288
suggestion for public http branches. Contact your manager for information
1289
on accessing this system if required.
1291
It should also be noted that best practice in this area is subject to
1292
change as things evolve. For example, once the Bazaar smart server on
1293
Launchpad supports server-side branching, the performance situation will
1294
be very different to what it is now (Jun 2007).
1297
Configuring the PQM Plug-In
1298
---------------------------
1300
While not strictly required, the PQM plugin automates a few things and
1301
reduces the chance of error. Before looking at the plugin, it helps to
1302
understand a little more how PQM operates. Basically, PQM requires an
1303
email indicating what you want it to do. The email typically looks like
1306
star-merge source-branch target-branch
1310
star-merge http://bzr.arbash-meinel.com/branches/bzr/jam-integration http://bazaar-vcs.org/bzr/bzr.dev
1312
Note that the command needs to be on one line. The subject of the email
1313
will be used for the commit message. The email also needs to be ``gpg``
1314
signed with a key that PQM accepts.
1316
The advantages of using the PQM plugin are:
1318
#. You can use the config policies to make it easy to set up public
1319
branches, so you don't have to ever type the full paths you want to merge
1322
#. It checks to make sure the public branch last revision matches the
1323
local last revision so you are submitting what you think you are.
1325
#. It uses the same public_branch and smtp sending settings as bzr-email,
1326
so if you have one set up, you have the other mostly set up.
1328
#. Thunderbird refuses to not wrap lines, and request lines are usually
1329
pretty long (you have 2 long URLs in there).
1331
Here are sample configuration settings for the PQM plugin. Here are the
1332
lines in bazaar.conf::
1335
email = Joe Smith <joe.smith@internode.on.net>
1336
smtp_server=mail.internode.on.net:25
1338
And here are the lines in ``locations.conf`` (or ``branch.conf`` for
1339
dirstate-tags branches)::
1341
[/home/joe/bzr/my-integration]
1342
push_location = sftp://joe-smith@bazaar.launchpad.net/%7Ejoe-smith/bzr/my-integration/
1343
push_location:policy = norecurse
1344
public_branch = http://bazaar.launchpad.net/~joe-smith/bzr/my-integration/
1345
public_branch:policy = appendpath
1346
pqm_email = Bazaar PQM <pqm@bazaar-vcs.org>
1347
pqm_branch = http://bazaar-vcs.org/bzr/bzr.dev
1349
Note that the push settings will be added by the first ``push`` on
1350
a branch. Indeed the preferred way to generate the lines above is to use
1351
``push`` with an argument, then copy-and-paste the other lines into
1358
Here is one possible recipe once the above environment is set up:
1360
#. pull bzr.dev => my-integration
1361
#. merge patch => my-integration
1362
#. fix up any final merge conflicts (NEWS being the big killer here).
1368
The ``push`` step is not required if ``my-integration`` is a checkout of
1371
Because of defaults, you can type a single message into commit and
1372
pqm-commit will reuse that.
1375
Tracking Change Acceptance
1376
--------------------------
1378
The web interface to PQM is https://pqm.bazaar-vcs.org/. After submitting
1379
a change, you can visit this URL to confirm it was received and placed in
1382
When PQM completes processing a change, an email is sent to you with the
1386
Reviewing Blueprints
1387
====================
1389
Blueprint Tracking Using Launchpad
1390
----------------------------------
1392
New features typically require a fair amount of discussion, design and
1393
debate. For Bazaar, that information is often captured in a so-called
1394
"blueprint" on our Wiki. Overall tracking of blueprints and their status
1395
is done using Launchpad's relevant tracker,
1396
https://blueprints.launchpad.net/bzr/. Once a blueprint for ready for
1397
review, please announce it on the mailing list.
1399
Alternatively, send an email begining with [RFC] with the proposal to the
1400
list. In some cases, you may wish to attach proposed code or a proposed
1401
developer document if that best communicates the idea. Debate can then
1402
proceed using the normal merge review processes.
1405
Recording Blueprint Review Feedback
1406
-----------------------------------
1408
Unlike its Bug Tracker, Launchpad's Blueprint Tracker doesn't currently
1409
(Jun 2007) support a chronological list of comment responses. Review
1410
feedback can either be recorded on the Wiki hosting the blueprints or by
1411
using Launchpad's whiteboard feature.
630
1414
Planning Releases
631
1415
=================
1420
As the two senior developers, Martin Pool and Robert Collins coordinate
1421
the overall Bazaar product development roadmap. Core developers provide
1422
input and review into this, particularly during sprints. It's totally
1423
expected that community members ought to be working on things that
1424
interest them the most. The roadmap is valuable though because it provides
1425
context for understanding where the product is going as a whole and why.
1428
Using Releases and Milestones in Launchpad
1429
------------------------------------------
1431
TODO ... (Exact policies still under discussion)
added
removed
doc/developers/HACKING.txt
