Merge branch 'master' into lilypond/translation

[lilypond.git] / Documentation / contributor / issues.itexi

@c -*- coding: utf-8; mode: texinfo; -*-
@node Issues
@chapter Issues

This chapter deals with defects, feature requests, and
miscellaneous development tasks.

@menu
* Introduction to issues::
* Bug Squad setup::
* Bug Squad checklists::
* Issue classification::
* Adding issues to the tracker::
* Summary of project status::
* Finding the cause of a regression::
@end menu


@node Introduction to issues
@section Introduction to issues

@warning{Unless otherwise specified, all the tasks in this chapter
are @qq{simple} tasks: they can be done by a normal user with
nothing more than a web browser, email, and lilypond.}

@qq{Issues} isn't just a politically-correct term for @qq{bug}.
We use the same tracker for feature requests and code TODOs, so
the term @qq{bug} wouldn't be accurate.  Despite the difference
between @qq{issue} and @qq{bug}, we call our team of contributors
who organize issues the @emph{Bug Squad}.

The Bug Squad is mainly composed of non-programmers -- their job
is to @emph{organize} issues, not solve them.  Their duties
include removing false bug reports, ensuring that any real bug
report contains enough information for developers, and checking
that a developer's fix actually resolves the problem.

New volunteers for the Bug Squad should contact the
@ref{Meisters, Bug Meister}.


@node Bug Squad setup
@section Bug Squad setup

We highly recommend that you configure your email to use effective
sorting; this can reduce your workload @emph{immensely}.  The
email folders names were chosen specifically to make them work if
you sort your folders alphabetically.

@enumerate

@item
Skim through every section of this chapter, @ref{Issues}.  Read in
detail any sections called @qq{Bug Squad...}, or any page linked
from @ref{Bug Squad checklists}.

@item
If you do not have one already, create a gmail account and send
the email address to the @ref{Meisters, Bug Meister}.

@item
Subscribe your gmail account to @code{bug-lilypond}.

@item
Configure your google code account:

@enumerate

@item
Wait until your gmail account is listed in:

@example
@uref{http://code.google.com/p/lilypond/people/list}
@end example

@item
Sign in to google code by clicking in the top-right corner of:

@example
@uref{http://code.google.com/p/lilypond/issues/list}
@end example

You cannot log if you have Google Sharing
@uref{http://www.googlesharing.net/} enabled.

@item
Go to your @qq{Profile}, and select @qq{Settings}.

@item
Scroll down to @qq{Issue change notification}, and make sure that
you have @emph{selected} @qq{If I starred the issue}.

@end enumerate

@item
Configure your email client:

@enumerate

@item
Any email sent with your gmail address in the @code{To:} or
@code{CC:} fields should go to a @code{bug-answers} folder.

When setting up your filtering rules, be aware that Google Code
might use different versions of your email address, such as ones
ending in @code{@@googlemail.com} or @code{@@gmail.com}.

@item
Any other email either from, or CC'd to,

@example
lilypond@@googlecode.com
@end example

@noindent
should go into a separate @code{bug-ignore} folder.  Alternately,
you may automatically delete these emails.

You will @strong{not read} these emails as part of your Bug Squad
duties.  If you are curious, go ahead and read them later, but it
does @strong{not} count as Bug Squad work.

@item
Any other email sent to (or CC'd to):

@example
bug-lilypond
@end example

@noindent
should go into a separate @code{bug-current} folder.

@end enumerate

@end enumerate


@node Bug Squad checklists
@section Bug Squad checklists

When you do Bug Squad work, start at the top of this page and work
your way down.  Stop when you've done 15 minutes.

Please use the email sorting described in @ref{Bug Squad setup}.
This means that (as Bug Squad members) you will only ever respond
to emails sent or CC'd to the @code{bug-lilypond} mailing list.


@subsubheading Emails to you personally

You are not expected to work on Bug Squad matters outside of your
15 minutes, but sometimes a confused user will send a bug report
(or an update to a report) to you personally.  If that happens,
please forward such emails to the @code{bug-lilypond} list so that
the currently-active Bug Squad member(s) can handle the message.


@subsubheading Daily schedule

The Bug Meister is omitted from the daily schedule.

@example
Sunday: Colin
Monday: Dmytro
Tuesday: James Bailey
Wednesday: Ralph
Thursday: Patrick
Friday: Urs
Saturday: Kieren
@end example


@subsubheading Emails to @code{bug-answers}

Some of these emails will be comments on issues that you added to
the tracker.

@itemize
If they are asking for more information, give the additional
information.

@item
If the email says that the issue was classified in some other
manner, read the rationale given and take that into account for
the next issue you add.

@item
Otherwise, move them to your @code{bug-ignore} folder.

@end itemize

Some of these emails will be discussions about Bug Squad work;
read those.


@subsubheading Emails to @code{bug-current}

Dealing with these emails is your main task.  Your job is to get
rid of these emails in the first method which is applicable:

@enumerate
@item
If the email has already been handled by a Bug Squad member (i.e.
check to see who else has replied to it), delete it.

@item
If the email is a question about how to use LilyPond, reply with
this response:

@example
For questions about how to use LilyPond, please read our
documentation available from:
  @uref{http://lilypond.org/website/manuals.html}
or ask the lilypond-user mailing list.
@end example

@item
If the email mentions @qq{the latest git}, or any version number
that has not yet been officially released, forward it to
@code{lilypond-devel}.

@item
If a bug report is not in the form of a Tiny example, direct the
user to resubmit the report with this response:

@example
I'm sorry, but due to our limited resources for handling bugs, we
can only accept reports in the form of Tiny examples.  Please see
step 2 in our bug reporting guidelines:
  @uref{http://lilypond.org/website/bug-reports.html}
@end example

@item
If anything is unclear, ask the user for more information.

How does the graphical output differ from what the user expected?
What version of lilypond was used (if not given) and operating
system (if this is a suspected cause of the problem)?  In short,
if you cannot understand what the problem is, ask the user to
explain more.  It is the user's responsibility to explain the
problem, not your responsibility to understand it.

@item
If the behavior is expected, the user should be told to read the
documentation:

@example
I believe that this is the expected behaviour -- please read our
documentation about this topic.  If you think that it really is a
mistake, please explain in more detail.  If you think that the
docs are unclear, please suggest an improvement as described by
@qq{Simple tasks -- Documentation} on:
  @uref{http://lilypond.org/website/help-us.html}
@end example

@item
If the issue already exists in the tracker, send an email to that
effect:

@example
This issue has already been reported; you can follow the
discussion and be notified about fixes here:
@end example

@noindent
(copy+paste the google code issue URL)

@item
Accept the report as described in
@ref{Adding issues to the tracker}.

@end enumerate

All emails should be CC'd to the @code{bug-lilypond} list so that
other Bug Squad members know that you have processed the email.

@warning{There is no option for @qq{ignore the bug report} -- if
you cannot find a reason to reject the report, you must accept
it.}


@ignore
@c Try omitting this from Bug Squad duties

@subheading Updates / discussion about issues

We try to keep discussions about issues on the tracker, but
sometimes it spills over onto email.  If discussion has ended with
no patch / resolution and at least @strong{3 days} have passed,
then either:

@itemize

@item
Summarize the recent discussion on the tracker, and add a link to
the original discussion.

@item
Add the comment @qq{there was some technical discussion which I
could not understand}, and include a link to the original
discussion.

We do not expect Bug Squad members to be programmers, or even to
be moderately-skilled users.  Your job is to keep track of issue
reports; it is @emph{perfectly acceptable} to not understand
discussions between advanced users and/or developers.

@end itemize
@end ignore


@subheading Regular maintenance

After @strong{every release} (both stable and unstable):

@itemize

@item
Regression test comparison: if anything has changed suspiciously,
ask if it was deliberate.  The official comparison is online, at:

@c NOTE: leave this here.  In this case, it's worth duplicating
@c       the link.  -gp
@example
@uref{http://lilypond.org/test/}
@end example

More information is available from in
@ref{Precompiled regression tests}.


@item
Issues to verify: try to reproduce the bug with the latest
version; if you cannot reproduce the bug, mark the item
@qq{Verified} (i.e. @qq{the fix has been verified to work}).

@example
@uref{http://code.google.com/p/lilypond/issues/list?can=7}
@end example

A few (approximately 10%) of these fixed issues relate to the
build system or fundamental architecture changes; there is no way
for you to verify these.  Leave those issues alone; somebody else
will handle them.

@end itemize


@ignore
@c try omitting from daily tasks for now. -gp

Once every @strong{two weeks} or so:

@itemize

@item
Check for any incorrectly-classified items in the tracker.  This
generally just means looking at the grid to see any items without
a Type or Priority.

@item
Check for any items with @code{label:patch}.  If it's been more
than a week since the last action on the issue, send an email to
-devel to remind them about it.  If the patch was withdrawn for
more work, then remove the @code{patch} label.

@example
@uref{http://code.google.com/p/lilypond/issues/list?can=2&q=label:patch}
@end example

@end itemize


@subheading Irregular maintenance

@warning{These tasks are a lot of work; gathering more volunteers
to help is definitely recommended.  However, the Bug Squad should
handle the organization and training of new volunteers.}

Once every year or two:

@itemize

@item
Checking all regtests: although we have a system for checking the
regtests between two versions, occasionally a bug will slip
through the cracks.  It is therefore good to manually examine all
the regtests (compare the images to the text description).  More
information is available from in @ref{Regression tests}.


@item
Checking all issues: we try to mark each Issue @q{fixed} when we
fix it, but occasionally one or two issues will slip through the
cracks.  It is therefore good to check all Issues.  If you see the
same (broken) output as the initial report, then simply post a
@qq{Problem still exists in 2.x.y} message to the issue.

@end itemize

@end ignore


@node Issue classification
@section Issue classification

The Bug Squad should classify issues according to the guidelines
given by developers.  Every issue should have a Status, Type, and
Priority; the other fields are optional.

@subheading Status (mandatory)

Open issues:

@itemize

@item
New: the item was added by a non-member, despite numerous warnings
not to do this.  Should be reviewed by a member of the Bug Squad.

@item
Accepted: the Bug Squad added it, or reviewed the item.

@item
Started: a contributor is working on a fix.  Owner should change
to be this contributor.

@end itemize


Closed issues:

@itemize

@item
Invalid: issue should not have been added in the current state.

@item
Duplicate: issue already exists in the tracker.

@item
Fixed: a contributor claims to have fixed the bug.  The Bug
Squad should check the fix with the next official binary release
(not by compiling the source from git).  Owner should be set to
that contributor.

@item
Verified: Bug Squad has confirmed that the issue is closed.  This
means that nobody should ever need look at the report again -- if
there is any information in the issue that should be kept, open a
new issue for that info.

@end itemize


@subheading Owner (optional)

Newly-added issues should have @emph{no owner}.  When a
contributor indicates that he has Started or Fixed an item, he
should become the owner.


@subheading Type (mandatory)

The issue's Type should be the first relevant item in this list.

@itemize

@item
Type-Collision: overlapping notation.

@item
Type-Defect: a problem in the core program.  (the @code{lilypond}
binary, scm files, fonts, etc).

@item
Type-Documentation: inaccurate, missing, confusing, or desired
additional info.  Must be fixable by editing a texinfo, ly, or scm
file.

@item
Type-Build: problem or desired features in the build system.  This
includes the makefiles, stepmake, python scripts, and GUB.

@item
Type-Scripts: problem or desired feature in the non-build-system
scripts.  Mostly used for convert-ly, lilypond-book, etc.

@item
Type-Enhancement: a feature request for the core program.  The
distinction between enhancement and defect isn't extremely clear;
when in doubt, mark it as enhancement.

@item
Type-Other: anything else.

@end itemize


@subheading Priority (mandatory)

Currently, only Critical items will block a stable release.

@itemize

@item
Priority-Critical: LilyPond segfaults, a regression (see below)
against a previous stable version or a regression against a fix
developed for this version. This does not apply where the
@qq{regression} occurred because a feature was removed
deliberately - this is not a bug.

@item
Priority-High: An issue which produces output which does not
accurately reflect the input (e.g. where the user would expect
an accidental, but none is shown) or which produces aesthetically
poor output in a situation which could be expected to crop up
frequently in real-world music.  It should not be used where the
problem can be avoided with a simple workaround.  It can also
be used to flag where new code in a development version is not
functioning as it should.  This level is also used for issues
which produce no output and fail to give the user a clue about
what's wrong.

@item
Priority-Medium: Normal priority - use this as the default.

@item
Priority-Low: A minor problem which produces slightly undesirable
output, or which will only occur in contrived examples, or which
is very easily worked around.

@item
Priority-Postponed: no fix planned.  Generally used for things
which nobody wants to touch.

@end itemize

Note that these are initial classifications and can be subject
to change by others in the development team.  For example, a
regression against an old stable version which hasn't been
noticed for a long time and which is unlikely to get fixed could
be downgraded from Priority-Critical by one of the programmers.

@subheading Opsys (optional)

Issues that only affect specific operating systems.


@subheading Other items (optional)

Other labels:

@itemize

@item
Regression: it used to work intentionally in an earlier
stable release.  If the earlier output was accidental (i.e. we
didn't try to stop a collision, but it just so happened that two
grobs didn't collide), then breaking it does not count as a
regression.

To help decide whether the change is a regression, and therefore
should be Priority-Critical, please adopt the following process:

@enumerate

@item
Are you certain the change is OK?  If so, do nothing.

@item
Are you certain that the change is bad?  Add it to the tracker
as a Critical issue, regression.

@item
If you're not certain either way, add it to the tracker as a
Critical issue, regression but be aware that it may be
recategorised or marked invalid.

@end enumerate

In particular, anything that breaks a regression test is a
regression.

@item
Patch: a patch to fix an issue is attached.

@item
Frog: the fix is believed to be suitable for a new contributor
(does not require a great deal of knowledge about LilyPond).  The
issue should also have an estimated time in a comment.

@item
Maintainability: hinders development of LilyPond.  For example,
improvements to the build system, or @qq{helper} python scripts.

@item
Bounty: somebody is willing to pay for the fix.  Only add this tag
if somebody has offered an exact figure in US dollars or euros.

@item
Warning: graphical output is fine, but lilypond prints a
false/misleading warning message.  Alternately, a warning should
be printed (such as a bar line error), but was not.  Also applies
to warnings when compiling the source code or generating
documentation.

@item
Security: might potentially be used.

@item
Performance: might potentially be used.

@end itemize

If you particularly want to add a label not in the list, go
ahead, but this is not recommended.


@node Adding issues to the tracker
@section Adding issues to the tracker

@warning{This should only be done by the Bug Squad or experienced
developers.  Normal users should not do this; instead, they should
follow the guidelines for @rweb{Bug reports}.}

In order to assign labels to issues, Bug Squad members should log
in to their google account before adding an item.

@subsubheading Normal issues

@enumerate

@item
Check if the issue falls into any previous category given on the
relevant checklists in @ref{Bug Squad checklists}.  If in doubt,
add a new issue for a report.  We would prefer to have some
incorrectly-added issues rather than lose information that should
have been added.

@item
Add the issue and classify it according to the guidelines in
@ref{Issue classification}.  In particular, the item should have
@code{Status}, @code{Type-}, and @code{Priority-} labels.

Include output with the first applicable method:

@itemize

@item
If the issue has a notation example which fits in one system,
generate a small @file{bug.preview.png} file with:

@example
lilypond -dpreview bug.ly
@end example

@item
If the issue has an example which requires more than one system
(i.e. a spacing bug), generate a @file{bug.png} file with:

@example
lilypond --png bug.ly
@end example

@item
If the issue requires one or two pages of output, then generate a
@file{bug.png} file with the normal:

@example
lilypond --png bug.ly
@end example

@item
If the issue cannot be shown with less than three pages, then
generate a @file{bug.pdf} file with:

@example
lilypond --pdf bug.ly
@end example

Note that this is likely to be extremely rare; most bugs should fit
into the first two categories above.


@end itemize

@item
After adding the issue, please send a response email to the same
group(s) that the initial patch was sent to.  If the initial email
was sent to multiple mailing lists (such as both @code{user} and
@code{bugs}), then reply to all those mailing lists as well.  The
email should contain a link to the issue you just added.

@end enumerate


@subsubheading Patch reminders

@warning{This is not a Bug Squad responsibility; we have a
separate person handling this task.}

There is a special category of issues: reminders of an existing
patch.  These should be added if a patch has been sent to a
lilypond mailing list (generally @code{lilypond-devel}, but they
sometimes appear on @code{bug-lilypond} as well) and has had no
discussion for at least @strong{3 days}.  Do not add issues for
patches under active discussion.

Before adding a patch-reminder issue, do a quick check to see if
it was pushed without sending any email.  This can be checked for
searching for relevant terms (from the patch subject or commit
message) on the webgit page:

@example
@uref{http://git.savannah.gnu.org/gitweb/?p=lilypond.git}
@end example

After adding the issue, please send a response email to the same
group(s) that the initial patch was sent to.  If the initial email
was sent to multiple mailing lists (such as both @code{bugs} and
@code{devel}), then reply to all those mailing lists as well.  The
email should contain a link to the issue you just added.



@node Summary of project status
@section Summary of project status

The best overview of our current status is given by the grid view:

@example
@uref{http://code.google.com/p/lilypond/issues/list?mode=grid&y=Priority&x=Type&cells=ids}
@end example

Also of interest might be the issues hindering future development:

@example
@uref{http://code.google.com/p/lilypond/issues/list?can=2&q=label:Maintainability&mode=grid&y=Priority&x=Type&cells=ids}
@end example

Finally, issues tagged with @code{Frog} indicates a task suitable
for a relatively new contributor.  The time given is a quick
(inaccurate) estimate of the time required for somebody who is
familiar with material in this manual, but does not know anything
else about LilyPond development.

@example
@uref{http://code.google.com/p/lilypond/issues/list?can=2&q=label:Frog&mode=grid&y=Priority&x=Type&cells=ids}
@end example


@node Finding the cause of a regression
@section Finding the cause of a regression

@warning{This is not a @qq{simple} task; it requires a fair amount
of technical knowledge.}

Git has special functionality to help tracking down the exact
commit which causes a problem.  See the git manual page for
@code{git bisect}.  This is a job that non-programmers can do,
although it requires familiarity with git, ability to compile
LilyPond, and generally a fair amount of technical knowledge.  A
brief summary is given below, but you may need to consult other
documentation for in-depth explanations.

Even if you are not familiar with git or are not able to compile
LilyPond you can still help to narrow down the cause of a
regression simply by downloading the binary releases of different
LilyPond versions and testing them for the regression.  Knowing
which version of LilyPond first exhibited the regression is
helpful to a developer as it shortens the @code{git bisect}
procedure.

Once a problematic commit is identified, the programmers' job is
much easier.  In fact, for most regression bugs, the majority of
the time is spent simply finding the problematic commit.

More information is in @ref{Regression tests}.

@subheading git bisect setup

We need to set up the bisect for each problem we want to
investigate.

Suppose we have an input file which compiled in version 2.13.32,
but fails in version 2.13.38 and above.

@enumerate
@item
Begin the process:

@example
git bisect start
@end example

@item
Give it the earliest known bad tag:

@example
git bisect bad release/2.13.38-1
@end example

(you can see tags with: @code{git tag} )

@item
Give it the latest known good tag:

@example
git bisect good release/2.13.32-1
@end example

You should now see something like:
@example
Bisecting: 195 revisions left to test after this (roughly 8 steps)
[b17e2f3d7a5853a30f7d5a3cdc6b5079e77a3d2a] Web: Announcement
update for the new @qq{LilyPond Report}.
@end example

@end enumerate

@subheading git bisect actual

@enumerate

@item
Compile the source:

@example
make
@end example

@item
Test your input file:

@example
out/bin/lilypond test.ly
@end example

@item
Test results?

@itemize
@item
Does it crash, or is the output bad?  If so:

@example
git bisect bad
@end example

@item
Does your input file produce good output?  If so:

@example
git bisect good
@end example

@end itemize

@item
Once the exact problem commit has been identified, git will inform
you with a message like:

@example
6d28aebbaaab1be9961a00bf15a1ef93acb91e30 is the first bad commit
%%% ... blah blah blah ...
@end example

If there is still a range of commits, then git will automatically
select a new version for you to test.  Go to step #1.

@end enumerate

@subheading Recommendation: use two terminal windows

@itemize
@item
One window is open to the @code{build/} directory, and alternates
between these commands:

@example
make
out/bin/lilypond test.ly
@end example

@item
One window is open to the top source directory, and alternates
between these commands:

@example
git bisect good
git bisect bad
@end example

@end itemize