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
185
83
=====================================
187
The development team follows many practices including:
85
The development team follows many best-practices including:
189
87
* a public roadmap and planning process in which anyone can participate
202
100
* Launchpad - https://launchpad.net/
204
* Bazaar - http://bazaar.canonical.com/
102
* Bazaar - http://bazaar-vcs.org/
104
* Bundle Buggy - http://bundlebuggy.aaronbentley.com/
206
106
* Patch Queue Manager - https://launchpad.net/pqm/
208
For further information, see <http://wiki.bazaar.canonical.com/BzrDevelopment>.
108
For further information, see http://bazaar-vcs.org/BzrDevelopment.
111
A Closer Look at the Merge & Review Process
112
===========================================
114
If you'd like to propose a change, please post to the
115
bazaar@lists.canonical.com list with a bundle, patch, or link to a
116
branch. Put '[PATCH]' or '[MERGE]' in the subject so Bundle Buggy
117
can pick it out, and explain the change in the email message text.
118
Remember to update the NEWS file as part of your change if it makes any
119
changes visible to users or plugin developers. Please include a diff
120
against mainline if you're giving a link to a branch.
122
You can generate a bundle like this::
124
bzr bundle > mybundle.patch
126
A .patch extension is recommended instead of .bundle as many mail clients
127
will send the latter as a binary file. If a bundle would be too long or your
128
mailer mangles whitespace (e.g. implicitly converts Unix newlines to DOS
129
newlines), use the merge-directive command instead like this::
131
bzr merge-directive http://bazaar-vcs.org http://example.org/my_branch > my_directive.patch
133
See the help for details on the arguments to merge-directive.
135
Please do **NOT** put [PATCH] or [MERGE] in the subject line if you don't
136
want it to be merged. If you want comments from developers rather than
137
to be merged, you can put '[RFC]' in the subject line.
139
Anyone is welcome to review code. There are broadly three gates for
142
* Doesn't reduce test coverage: if it adds new methods or commands,
143
there should be tests for them. There is a good test framework
144
and plenty of examples to crib from, but if you are having trouble
145
working out how to test something feel free to post a draft patch
148
* Doesn't reduce design clarity, such as by entangling objects
149
we're trying to separate. This is mostly something the more
150
experienced reviewers need to help check.
152
* Improves bugs, features, speed, or code simplicity.
154
Code that goes in should pass all three. The core developers take care
155
to keep the code quality high and understandable while recognising that
156
perfect is sometimes the enemy of good. (It is easy for reviews to make
157
people notice other things which should be fixed but those things should
158
not hold up the original fix being accepted. New things can easily be
159
recorded in the Bug Tracker instead.)
161
Anyone can "vote" on the mailing list. Core developers can also vote using
162
Bundle Buggy. Here are the voting codes and their explanations.
164
:approve: Reviewer wants this submission merged.
165
:tweak: Reviewer wants this submission merged with small changes. (No
167
:abstain: Reviewer does not intend to vote on this patch.
168
:resubmit: Please make changes and resubmit for review.
169
:reject: Reviewer doesn't want this kind of change merged.
170
:comment: Not really a vote. Reviewer just wants to comment, for now.
172
If a change gets two approvals from core reviewers, and no rejections,
173
then it's OK to come in. Any of the core developers can bring it into the
174
bzr.dev trunk and backport it to maintenance branches if required. The
175
Release Manager will merge the change into the branch for a pending
176
release, if any. As a guideline, core developers usually merge their own
177
changes and volunteer to merge other contributions if they were the second
178
reviewer to agree to a change.
180
To track the progress of proposed changes, use Bundle Buggy. See
181
http://bundlebuggy.aaronbentley.com/help for a link to all the
182
outstanding merge requests together with an explanation of the columns.
183
Bundle Buggy will also mail you a link to track just your change.
213
186
Preparing a Sandbox for Making Changes to Bazaar
214
187
================================================
216
189
Bazaar supports many ways of organising your work. See
217
http://wiki.bazaar.canonical.com/SharedRepositoryLayouts for a summary of the
190
http://bazaar-vcs.org/SharedRepositoryLayouts for a summary of the
218
191
popular alternatives.
220
193
Of course, the best choice for you will depend on numerous factors:
274
251
Holds documentation on a whole range of things on Bazaar from the
275
252
origination of ideas within the project to information on Bazaar
276
253
features and use cases. Within this directory there is a subdirectory
277
for each translation into a human language. All the documentation
254
for each translation into a human language. All the documentation
278
255
is in the ReStructuredText markup language.
281
Documentation specifically targeted at Bazaar and plugin developers.
258
Documentation specifically targetted at Bazaar and plugin developers.
282
259
(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://people.canonical.com/~mwh/bzrlibapi/>.
299
See also the `Bazaar Architectural Overview
300
<http://doc.bazaar.canonical.com/developers/overview.html>`_.
263
Automatically-generated API reference information is available at
264
<http://starship.python.net/crew/mwh/bzrlibapi/>.
265
(There is an experimental editable version at
266
<http://starship.python.net/crew/mwh/bzrlibapi-oe/>.)
267
See also the `Essential Domain Classes`_
268
section of this guide.
271
Essential Domain Classes
272
########################
274
Introducing the Object Model
275
============================
277
The core domain objects within the bazaar model are:
287
Transports are explained below. See http://bazaar-vcs.org/Classes/
288
for an introduction to the other key classes.
293
The ``Transport`` layer handles access to local or remote directories.
294
Each Transport object acts like a logical connection to a particular
295
directory, and it allows various operations on files within it. You can
296
*clone* a transport to get a new Transport connected to a subdirectory or
299
Transports are not used for access to the working tree. At present
300
working trees are always local and they are accessed through the regular
301
Python file io mechanisms.
306
Transports work in URLs. Take note that URLs are by definition only
307
ASCII - the decision of how to encode a Unicode string into a URL must be
308
taken at a higher level, typically in the Store. (Note that Stores also
309
escape filenames which cannot be safely stored on all filesystems, but
310
this is a different level.)
312
The main reason for this is that it's not possible to safely roundtrip a
313
URL into Unicode and then back into the same URL. The URL standard
314
gives a way to represent non-ASCII bytes in ASCII (as %-escapes), but
315
doesn't say how those bytes represent non-ASCII characters. (They're not
316
guaranteed to be UTF-8 -- that is common but doesn't happen everywhere.)
318
For example if the user enters the url ``http://example/%e0`` there's no
319
way to tell whether that character represents "latin small letter a with
320
grave" in iso-8859-1, or "latin small letter r with acute" in iso-8859-2
321
or malformed UTF-8. So we can't convert their URL to Unicode reliably.
323
Equally problematic if we're given a url-like string containing non-ascii
324
characters (such as the accented a) we can't be sure how to convert that
325
to the correct URL, because we don't know what encoding the server expects
326
for those characters. (Although this is not totally reliable we might still
327
accept these and assume they should be put into UTF-8.)
329
A similar edge case is that the url ``http://foo/sweet%2Fsour`` contains
330
one directory component whose name is "sweet/sour". The escaped slash is
331
not a directory separator. If we try to convert URLs to regular Unicode
332
paths this information will be lost.
334
This implies that Transports must natively deal with URLs; for simplicity
335
they *only* deal with URLs and conversion of other strings to URLs is done
336
elsewhere. Information they return, such as from ``list_dir``, is also in
337
the form of URL components.
340
Coding Style Guidelines
341
#######################
346
``hasattr`` should not be used because it swallows exceptions including
347
``KeyboardInterrupt``. Instead, say something like ::
349
if getattr(thing, 'name', None) is None
355
Please write PEP-8__ compliant code.
357
__ http://www.python.org/peps/pep-0008.html
359
One often-missed requirement is that the first line of docstrings
360
should be a self-contained one-sentence summary.
362
We use 4 space indents for blocks, and never use tab characters. (In vim,
365
Lines should be no more than 79 characters if at all possible.
366
Lines that continue a long statement may be indented in either of
369
within the parenthesis or other character that opens the block, e.g.::
375
or indented by four spaces::
381
The first is considered clearer by some people; however it can be a bit
382
harder to maintain (e.g. when the method name changes), and it does not
383
work well if the relevant parenthesis is already far to the right. Avoid
386
self.legbone.kneebone.shinbone.toebone.shake_it(one,
392
self.legbone.kneebone.shinbone.toebone.shake_it(one,
398
self.legbone.kneebone.shinbone.toebone.shake_it(
401
For long lists, we like to add a trailing comma and put the closing
402
character on the following line. This makes it easier to add new items in
405
from bzrlib.goo import (
411
There should be spaces between function paramaters, but not between the
412
keyword name and the value::
414
call(1, 3, cheese=quark)
418
;(defface my-invalid-face
419
; '((t (:background "Red" :underline t)))
420
; "Face used to highlight invalid constructs or other uglyties"
423
(defun my-python-mode-hook ()
424
;; setup preferred indentation style.
425
(setq fill-column 79)
426
(setq indent-tabs-mode nil) ; no tabs, never, I will not repeat
427
; (font-lock-add-keywords 'python-mode
428
; '(("^\\s *\t" . 'my-invalid-face) ; Leading tabs
429
; ("[ \t]+$" . 'my-invalid-face) ; Trailing spaces
430
; ("^[ \t]+$" . 'my-invalid-face)); Spaces only
434
(add-hook 'python-mode-hook 'my-python-mode-hook)
436
The lines beginning with ';' are comments. They can be activated
437
if one want to have a strong notice of some tab/space usage
444
* Imports should be done at the top-level of the file, unless there is
445
a strong reason to have them lazily loaded when a particular
446
function runs. Import statements have a cost, so try to make sure
447
they don't run inside hot functions.
449
* Module names should always be given fully-qualified,
450
i.e. ``bzrlib.hashcache`` not just ``hashcache``.
456
Functions, methods or members that are "private" to bzrlib are given
457
a leading underscore prefix. Names without a leading underscore are
458
public not just across modules but to programmers using bzrlib as an
459
API. As a consequence, a leading underscore is appropriate for names
460
exposed across modules but that are not to be exposed to bzrlib API
463
We prefer class names to be concatenated capital words (``TestCase``)
464
and variables, methods and functions to be lowercase words joined by
465
underscores (``revision_id``, ``get_revision``).
467
For the purposes of naming some names are treated as single compound
468
words: "filename", "revno".
470
Consider naming classes as nouns and functions/methods as verbs.
472
Try to avoid using abbreviations in names, because there can be
473
inconsistency if other people use the full name.
479
``revision_id`` not ``rev_id`` or ``revid``
481
Functions that transform one thing to another should be named ``x_to_y``
482
(not ``x2y`` as occurs in some old code.)
488
Python destructors (``__del__``) work differently to those of other
489
languages. In particular, bear in mind that destructors may be called
490
immediately when the object apparently becomes unreferenced, or at some
491
later time, or possibly never at all. Therefore we have restrictions on
492
what can be done inside them.
494
0. If you think you need to use a ``__del__`` method ask another
495
developer for alternatives. If you do need to use one, explain
498
1. Never rely on a ``__del__`` method running. If there is code that
499
must run, do it from a ``finally`` block instead.
501
2. Never ``import`` from inside a ``__del__`` method, or you may crash the
504
3. In some places we raise a warning from the destructor if the object
505
has not been cleaned up or closed. This is considered OK: the warning
506
may not catch every case but it's still useful sometimes.
512
In some places we have variables which point to callables that construct
513
new instances. That is to say, they can be used a lot like class objects,
514
but they shouldn't be *named* like classes:
516
> I think that things named FooBar should create instances of FooBar when
517
> called. Its plain confusing for them to do otherwise. When we have
518
> something that is going to be used as a class - that is, checked for via
519
> isinstance or other such idioms, them I would call it foo_class, so that
520
> it is clear that a callable is not sufficient. If it is only used as a
521
> factory, then yes, foo_factory is what I would use.
527
Several places in Bazaar use (or will use) a registry, which is a
528
mapping from names to objects or classes. The registry allows for
529
loading in registered code only when it's needed, and keeping
530
associated information such as a help string or description.
533
InterObject and multiple dispatch
534
=================================
536
The ``InterObject`` provides for two-way `multiple dispatch`__: matching
537
up for example a source and destination repository to find the right way
538
to transfer data between them.
540
.. __: http://en.wikipedia.org/wiki/Multiple_dispatch
542
There is a subclass ``InterObject`` classes for each type of object that is
543
dispatched this way, e.g. ``InterRepository``. Calling ``.get()`` on this
544
class will return an ``InterObject`` instance providing the best match for
545
those parameters, and this instance then has methods for operations
548
inter = InterRepository.get(source_repo, target_repo)
549
inter.fetch(revision_id)
551
``InterRepository`` also acts as a registry-like object for its
552
subclasses, and they can be added through ``.register_optimizer``. The
553
right one to run is selected by asking each class, in reverse order of
554
registration, whether it ``.is_compatible`` with the relevant objects.
559
To make startup time faster, we use the ``bzrlib.lazy_import`` module to
560
delay importing modules until they are actually used. ``lazy_import`` uses
561
the same syntax as regular python imports. So to import a few modules in a
564
from bzrlib.lazy_import import lazy_import
565
lazy_import(globals(), """
574
revision as _mod_revision,
576
import bzrlib.transport
580
At this point, all of these exist as a ``ImportReplacer`` object, ready to
581
be imported once a member is accessed. Also, when importing a module into
582
the local namespace, which is likely to clash with variable names, it is
583
recommended to prefix it as ``_mod_<module>``. This makes it clearer that
584
the variable is a module, and these object should be hidden anyway, since
585
they shouldn't be imported into other namespaces.
587
While it is possible for ``lazy_import()`` to import members of a module
588
when using the ``from module import member`` syntax, it is recommended to
589
only use that syntax to load sub modules ``from module import submodule``.
590
This is because variables and classes can frequently be used without
591
needing a sub-member for example::
593
lazy_import(globals(), """
594
from module import MyClass
598
return isinstance(x, MyClass)
600
This will incorrectly fail, because ``MyClass`` is a ``ImportReplacer``
601
object, rather than the real class.
603
It also is incorrect to assign ``ImportReplacer`` objects to other variables.
604
Because the replacer only knows about the original name, it is unable to
605
replace other variables. The ``ImportReplacer`` class will raise an
606
``IllegalUseOfScopeReplacer`` exception if it can figure out that this
607
happened. But it requires accessing a member more than once from the new
608
variable, so some bugs are not detected right away.
614
The null revision is the ancestor of all revisions. Its revno is 0, its
615
revision-id is ``null:``, and its tree is the empty tree. When referring
616
to the null revision, please use ``bzrlib.revision.NULL_REVISION``. Old
617
code sometimes uses ``None`` for the null revision, but this practice is
621
Object string representations
622
=============================
624
Python prints objects using their ``__repr__`` method when they are
625
written to logs, exception tracebacks, or the debugger. We want
626
objects to have useful representations to help in determining what went
629
If you add a new class you should generally add a ``__repr__`` method
630
unless there is an adequate method in a parent class. There should be a
633
Representations should typically look like Python constructor syntax, but
634
they don't need to include every value in the object and they don't need
635
to be able to actually execute. They're to be read by humans, not
636
machines. Don't hardcode the classname in the format, so that we get the
637
correct value if the method is inherited by a subclass. If you're
638
printing attributes of the object, including strings, you should normally
639
use ``%r`` syntax (to call their repr in turn).
641
Try to avoid the representation becoming more than one or two lines long.
642
(But balance this against including useful information, and simplicity of
645
Because repr methods are often called when something has already gone
646
wrong, they should be written somewhat more defensively than most code.
647
The object may be half-initialized or in some other way in an illegal
648
state. The repr method shouldn't raise an exception, or it may hide the
649
(probably more useful) underlying exception.
654
return '%s(%r)' % (self.__class__.__name__,
661
A bare ``except`` statement will catch all exceptions, including ones that
662
really should terminate the program such as ``MemoryError`` and
663
``KeyboardInterrupt``. They should rarely be used unless the exception is
664
later re-raised. Even then, think about whether catching just
665
``Exception`` (which excludes system errors in Python2.5 and later) would
672
All code should be exercised by the test suite. See `Guide to Testing
673
Bazaar <testing.html>`_ for detailed information about writing tests.
741
Processing Command Lines
742
------------------------
744
bzrlib has a standard framework for parsing command lines and calling
745
processing routines associated with various commands. See builtins.py
746
for numerous examples.
749
Standard Parameter Types
750
------------------------
752
There are some common requirements in the library: some parameters need to be
753
unicode safe, some need byte strings, and so on. At the moment we have
754
only codified one specific pattern: Parameters that need to be unicode
755
should be checked via ``bzrlib.osutils.safe_unicode``. This will coerce the
756
input into unicode in a consistent fashion, allowing trivial strings to be
757
used for programmer convenience, but not performing unpredictably in the
758
presence of different locales.
764
(The strategy described here is what we want to get to, but it's not
765
consistently followed in the code at the moment.)
767
bzrlib is intended to be a generically reusable library. It shouldn't
768
write messages to stdout or stderr, because some programs that use it
769
might want to display that information through a GUI or some other
772
We can distinguish two types of output from the library:
774
1. Structured data representing the progress or result of an
775
operation. For example, for a commit command this will be a list
776
of the modified files and the finally committed revision number
779
These should be exposed either through the return code or by calls
780
to a callback parameter.
782
A special case of this is progress indicators for long-lived
783
operations, where the caller should pass a ProgressBar object.
785
2. Unstructured log/debug messages, mostly for the benefit of the
786
developers or users trying to debug problems. This should always
787
be sent through ``bzrlib.trace`` and Python ``logging``, so that
788
it can be redirected by the client.
790
The distinction between the two is a bit subjective, but in general if
791
there is any chance that a library would want to see something as
792
structured data, we should make it so.
794
The policy about how output is presented in the text-mode client
795
should be only in the command-line tool.
802
Bazaar has online help for various topics through ``bzr help COMMAND`` or
803
equivalently ``bzr command -h``. We also have help on command options,
804
and on other help topics. (See ``help_topics.py``.)
806
As for python docstrings, the first paragraph should be a single-sentence
807
synopsis of the command.
809
The help for options should be one or more proper sentences, starting with
810
a capital letter and finishing with a full stop (period).
812
All help messages and documentation should have two spaces between
816
Handling Errors and Exceptions
817
==============================
819
Commands should return non-zero when they encounter circumstances that
820
the user should really pay attention to - which includes trivial shell
823
Recommended values are:
826
1. Conflicts in merge-like operations, or changes are present in
827
diff-like operations.
828
2. Unrepresentable diff changes (i.e. binary files that we cannot show
830
3. An error or exception has occurred.
831
4. An internal error occurred (one that shows a traceback.)
833
Errors are handled through Python exceptions. Exceptions should be defined
834
inside bzrlib.errors, so that we can see the whole tree at a glance.
836
We broadly classify errors as either being either internal or not,
837
depending on whether ``internal_error`` is set or not. If we think it's our
838
fault, we show a backtrace, an invitation to report the bug, and possibly
839
other details. This is the default for errors that aren't specifically
840
recognized as being caused by a user error. Otherwise we show a briefer
841
message, unless -Derror was given.
843
Many errors originate as "environmental errors" which are raised by Python
844
or builtin libraries -- for example IOError. These are treated as being
845
our fault, unless they're caught in a particular tight scope where we know
846
that they indicate a user errors. For example if the repository format
847
is not found, the user probably gave the wrong path or URL. But if one of
848
the files inside the repository is not found, then it's our fault --
849
either there's a bug in bzr, or something complicated has gone wrong in
850
the environment that means one internal file was deleted.
852
Many errors are defined in ``bzrlib/errors.py`` but it's OK for new errors
853
to be added near the place where they are used.
855
Exceptions are formatted for the user by conversion to a string
856
(eventually calling their ``__str__`` method.) As a convenience the
857
``._fmt`` member can be used as a template which will be mapped to the
858
error's instance dict.
860
New exception classes should be defined when callers might want to catch
861
that exception specifically, or when it needs a substantially different
864
Exception strings should start with a capital letter and should not have a
865
final fullstop. If long, they may contain newlines to break the text.
871
Do not use the Python ``assert`` statement, either in tests or elsewhere.
872
A source test checks that it is not used. It is ok to explicitly raise
877
* It makes the behaviour vary depending on whether bzr is run with -O
878
or not, therefore giving a chance for bugs that occur in one case or
879
the other, several of which have already occurred: assertions with
880
side effects, code which can't continue unless the assertion passes,
881
cases where we should give the user a proper message rather than an
883
* It's not that much shorter than an explicit if/raise.
884
* It tends to lead to fuzzy thinking about whether the check is
885
actually needed or not, and whether it's an internal error or not
886
* It tends to cause look-before-you-leap patterns.
887
* It's unsafe if the check is needed to protect the integrity of the
889
* It tends to give poor messages since the developer can get by with
890
no explanatory text at all.
891
* We can't rely on people always running with -O in normal use, so we
892
can't use it for tests that are actually expensive.
893
* Expensive checks that help developers are better turned on from the
894
test suite or a -D flag.
895
* If used instead of ``self.assert*()`` in tests it makes them falsely pass with -O.
901
When you change bzrlib, please update the relevant documentation for the
902
change you made: Changes to commands should update their help, and
903
possibly end user tutorials; changes to the core library should be
904
reflected in API documentation.
909
If you make a user-visible change, please add a note to the NEWS file.
910
The description should be written to make sense to someone who's just
911
a user of bzr, not a developer: new functions or classes shouldn't be
912
mentioned, but new commands, changes in behaviour or fixed nontrivial
913
bugs should be listed. See the existing entries for an idea of what
916
Within each release, entries in the news file should have the most
917
user-visible changes first. So the order should be approximately:
919
* changes to existing behaviour - the highest priority because the
920
user's existing knowledge is incorrect
921
* new features - should be brought to their attention
922
* bug fixes - may be of interest if the bug was affecting them, and
923
should include the bug number if any
924
* major documentation changes
925
* changes to internal interfaces
927
People who made significant contributions to each change are listed in
928
parenthesis. This can include reporting bugs (particularly with good
929
details or reproduction recipes), submitting patches, etc.
934
The docstring of a command is used by ``bzr help`` to generate help output
935
for the command. The list 'takes_options' attribute on a command is used by
936
``bzr help`` to document the options for the command - the command
937
docstring does not need to document them. Finally, the '_see_also'
938
attribute on a command can be used to reference other related help topics.
943
Functions, methods, classes and modules should have docstrings
944
describing how they are used.
946
The first line of the docstring should be a self-contained sentence.
948
For the special case of Command classes, this acts as the user-visible
949
documentation shown by the help command.
951
The docstrings should be formatted as reStructuredText_ (like this
952
document), suitable for processing using the epydoc_ tool into HTML
955
.. _reStructuredText: http://docutils.sourceforge.net/rst.html
956
.. _epydoc: http://epydoc.sourceforge.net/
368
959
General Guidelines
369
960
==================
632
1206
how to set it up and configure it.
1212
Setting Up Your Workspace for Reviews
1213
-------------------------------------
1215
TODO: Incorporate John Arbash Meinel's detailed email to Ian C on the
1216
numerous ways of setting up integration branches.
1219
The Review Checklist
1220
--------------------
1222
See `A Closer Look at the Merge & Review Process`_
1223
for information on the gates used to decide whether code can be merged
1224
or not and details on how review results are recorded and communicated.
1227
The Importance of Timely Reviews
1228
--------------------------------
1230
Good reviews do take time. They also regularly require a solid
1231
understanding of the overall code base. In practice, this means a small
1232
number of people often have a large review burden - with knowledge comes
1233
responsibility. No one like their merge requests sitting in a queue going
1234
nowhere, so reviewing sooner rather than later is strongly encouraged.
1243
Of the many workflows supported by Bazaar, the one adopted for Bazaar
1244
development itself is known as "Decentralized with automatic gatekeeper".
1245
To repeat the explanation of this given on
1246
http://bazaar-vcs.org/Workflows:
1249
In this workflow, each developer has their own branch or
1250
branches, plus read-only access to the mainline. A software gatekeeper
1251
(e.g. PQM) has commit rights to the main branch. When a developer wants
1252
their work merged, they request the gatekeeper to merge it. The gatekeeper
1253
does a merge, a compile, and runs the test suite. If the code passes, it
1254
is merged into the mainline.
1256
In a nutshell, here's the overall submission process:
1258
#. get your work ready (including review except for trivial changes)
1259
#. push to a public location
1260
#. ask PQM to merge from that location
1263
At present, PQM always takes the changes to merge from a branch
1264
at a URL that can be read by it. For Bazaar, that means a public,
1265
typically http, URL.
1267
As a result, the following things are needed to use PQM for submissions:
1269
#. A publicly available web server
1270
#. Your OpenPGP key registered with PQM (contact RobertCollins for this)
1271
#. The PQM plugin installed and configured (not strictly required but
1272
highly recommended).
1275
Selecting a Public Branch Location
1276
----------------------------------
1278
If you don't have your own web server running, branches can always be
1279
pushed to Launchpad. Here's the process for doing that:
1281
Depending on your location throughout the world and the size of your
1282
repository though, it is often quicker to use an alternative public
1283
location to Launchpad, particularly if you can set up your own repo and
1284
push into that. By using an existing repo, push only needs to send the
1285
changes, instead of the complete repository every time. Note that it is
1286
easy to register branches in other locations with Launchpad so no benefits
1287
are lost by going this way.
1290
For Canonical staff, http://people.ubuntu.com/~<user>/ is one
1291
suggestion for public http branches. Contact your manager for information
1292
on accessing this system if required.
1294
It should also be noted that best practice in this area is subject to
1295
change as things evolve. For example, once the Bazaar smart server on
1296
Launchpad supports server-side branching, the performance situation will
1297
be very different to what it is now (Jun 2007).
1300
Configuring the PQM Plug-In
1301
---------------------------
1303
While not strictly required, the PQM plugin automates a few things and
1304
reduces the chance of error. Before looking at the plugin, it helps to
1305
understand a little more how PQM operates. Basically, PQM requires an
1306
email indicating what you want it to do. The email typically looks like
1309
star-merge source-branch target-branch
1313
star-merge http://bzr.arbash-meinel.com/branches/bzr/jam-integration http://bazaar-vcs.org/bzr/bzr.dev
1315
Note that the command needs to be on one line. The subject of the email
1316
will be used for the commit message. The email also needs to be ``gpg``
1317
signed with a key that PQM accepts.
1319
The advantages of using the PQM plugin are:
1321
#. You can use the config policies to make it easy to set up public
1322
branches, so you don't have to ever type the full paths you want to merge
1325
#. It checks to make sure the public branch last revision matches the
1326
local last revision so you are submitting what you think you are.
1328
#. It uses the same public_branch and smtp sending settings as bzr-email,
1329
so if you have one set up, you have the other mostly set up.
1331
#. Thunderbird refuses to not wrap lines, and request lines are usually
1332
pretty long (you have 2 long URLs in there).
1334
Here are sample configuration settings for the PQM plugin. Here are the
1335
lines in bazaar.conf::
1338
email = Joe Smith <joe.smith@internode.on.net>
1339
smtp_server=mail.internode.on.net:25
1341
And here are the lines in ``locations.conf`` (or ``branch.conf`` for
1342
dirstate-tags branches)::
1344
[/home/joe/bzr/my-integration]
1345
push_location = sftp://joe-smith@bazaar.launchpad.net/%7Ejoe-smith/bzr/my-integration/
1346
push_location:policy = norecurse
1347
public_branch = http://bazaar.launchpad.net/~joe-smith/bzr/my-integration/
1348
public_branch:policy = appendpath
1349
pqm_email = Bazaar PQM <pqm@bazaar-vcs.org>
1350
pqm_branch = http://bazaar-vcs.org/bzr/bzr.dev
1352
Note that the push settings will be added by the first ``push`` on
1353
a branch. Indeed the preferred way to generate the lines above is to use
1354
``push`` with an argument, then copy-and-paste the other lines into
1361
Here is one possible recipe once the above environment is set up:
1363
#. pull bzr.dev => my-integration
1364
#. merge patch => my-integration
1365
#. fix up any final merge conflicts (NEWS being the big killer here).
1371
The ``push`` step is not required if ``my-integration`` is a checkout of
1374
Because of defaults, you can type a single message into commit and
1375
pqm-commit will reuse that.
1378
Tracking Change Acceptance
1379
--------------------------
1381
The web interface to PQM is https://pqm.bazaar-vcs.org/. After submitting
1382
a change, you can visit this URL to confirm it was received and placed in
1385
When PQM completes processing a change, an email is sent to you with the
1389
Reviewing Blueprints
1390
====================
1392
Blueprint Tracking Using Launchpad
1393
----------------------------------
1395
New features typically require a fair amount of discussion, design and
1396
debate. For Bazaar, that information is often captured in a so-called
1397
"blueprint" on our Wiki. Overall tracking of blueprints and their status
1398
is done using Launchpad's relevant tracker,
1399
https://blueprints.launchpad.net/bzr/. Once a blueprint for ready for
1400
review, please announce it on the mailing list.
1402
Alternatively, send an email begining with [RFC] with the proposal to the
1403
list. In some cases, you may wish to attach proposed code or a proposed
1404
developer document if that best communicates the idea. Debate can then
1405
proceed using the normal merge review processes.
1408
Recording Blueprint Review Feedback
1409
-----------------------------------
1411
Unlike its Bug Tracker, Launchpad's Blueprint Tracker doesn't currently
1412
(Jun 2007) support a chronological list of comment responses. Review
1413
feedback can either be recorded on the Wiki hosting the blueprints or by
1414
using Launchpad's whiteboard feature.
636
1417
Planning Releases
637
1418
=================
1423
As the two senior developers, Martin Pool and Robert Collins coordinate
1424
the overall Bazaar product development roadmap. Core developers provide
1425
input and review into this, particularly during sprints. It's totally
1426
expected that community members ought to be working on things that
1427
interest them the most. The roadmap is valuable though because it provides
1428
context for understanding where the product is going as a whole and why.
1431
Using Releases and Milestones in Launchpad
1432
------------------------------------------
1434
TODO ... (Exact policies still under discussion)
added
removed
doc/developers/HACKING.txt
