[FFmpeg-cvslog] doc: update developer guide
Luca Barbato
git at videolan.org
Thu Apr 14 03:24:36 CEST 2011
ffmpeg | branch: master | Luca Barbato <lu_zero at gentoo.org> | Sat Apr 9 23:54:31 2011 +0200| [4c362a5212cf16e888e0ef51c3d6b9866152ef5f] | committer: Luca Barbato
doc: update developer guide
Refer to the current submission policy and refer to FATE in the
Regression Test section.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4c362a5212cf16e888e0ef51c3d6b9866152ef5f
---
doc/developer.texi | 221 ++++++++++++++++++++++------------------------------
1 files changed, 93 insertions(+), 128 deletions(-)
diff --git a/doc/developer.texi b/doc/developer.texi
index ec196d7..ab736d7 100644
--- a/doc/developer.texi
+++ b/doc/developer.texi
@@ -23,16 +23,22 @@ audio or video streams.
@end itemize
- at section Integrating libavcodec or libavformat in your program
-
-You can integrate all the source code of the libraries to link them
-statically to avoid any version problem. All you need is to provide a
-'config.mak' and a 'config.h' in the parent directory. See the defines
-generated by ./configure to understand what is needed.
-
-You can use libavcodec or libavformat in your commercial program, but
- at emph{any patch you make must be published}. The best way to proceed is
-to send your patches to the Libav mailing list.
+ at section Integrating libav in your program
+
+Shared libraries should be used whenever is possible in order to reduce
+the effort distributors have to pour to support programs and to ensure
+only the public api is used.
+
+You can use Libav in your commercial program, but you must abide to the
+license, LGPL or GPL depending on the specific features used, please refer
+to @url{http://libav.org/legal.html} for a quick checklist and to
+ at url{http://git.libav.org/?p=libav.git;a=blob;f=COPYING.GPLv2},
+ at url{http://git.libav.org/?p=libav.git;a=blob;f=COPYING.GPLv3},
+ at url{http://git.libav.org/?p=libav.git;a=blob;f=COPYING.LGPLv2.1},
+ at url{http://git.libav.org/?p=libav.git;a=blob;f=COPYING.LGPLv3} for the
+exact text of the licenses.
+Any modification to the source code can be suggested for inclusion.
+The best way to proceed is to send your patches to the Libav mailing list.
@anchor{Coding Rules}
@section Coding Rules
@@ -129,17 +135,33 @@ should also be avoided if they don't make the code easier to understand.
an "or any later version" clause is also acceptable, but LGPL is
preferred.
@item
- You must not commit code which breaks Libav! (Meaning unfinished but
- enabled code which breaks compilation or compiles but does not work or
- breaks the regression tests)
- You can commit unfinished stuff (for testing etc), but it must be disabled
- (#ifdef etc) by default so it does not interfere with other developers'
- work.
+ All the patches MUST be reviewed in the mailing list before they are
+ committed.
+ at item
+ The Libav coding style should remain consistent. Changes to
+ conform will be suggested during the review or implemented on commit.
+ at item
+ Patches should be generated using @code{git format-patch} or directly sent
+ using @code{git send-email}.
+ Please make sure you give the proper credit by setting the correct author
+ in the commit.
@item
- You do not have to over-test things. If it works for you, and you think it
- should work for others, then commit. If your code has problems
- (portability, triggers compiler bugs, unusual environment etc) they will be
- reported and eventually fixed.
+ The commit message should have a short first line in the form of
+ @samp{topic: short description} as header, separated by a newline
+ from the body consting in few lines explaining the reason of the patch.
+ Referring to the issue on the bug tracker does not exempt to report an
+ excerpt of the bug.
+ at item
+ Work in progress patches should be sent to the mailing list with the [WIP]
+ or the [RFC] tag.
+ at item
+ Branches in public personal repos are advised as way to
+ work on issues collaboratively.
+ at item
+ You do not have to over-test things. If it works for you and you think it
+ should work for others, send it to the mailing list for review.
+ If you have doubt about portability please state it in the submission so
+ people with specific hardware could test it.
@item
Do not commit unrelated changes together, split them into self-contained
pieces. Also do not forget that if part B depends on part A, but A does not
@@ -147,70 +169,32 @@ should also be avoided if they don't make the code easier to understand.
Keeping changes well split into self-contained parts makes reviewing and
understanding them on the commit log mailing list easier. This also helps
in case of debugging later on.
- Also if you have doubts about splitting or not splitting, do not hesitate to
- ask/discuss it on the developer mailing list.
- at item
- Do not change behavior of the programs (renaming options etc) or public
- API or ABI without first discussing it on the libav-devel mailing list.
- Do not remove functionality from the code. Just improve!
-
- Note: Redundant code can be removed.
- at item
- Do not commit changes to the build system (Makefiles, configure script)
- which change behavior, defaults etc, without asking first. The same
- applies to compiler warning fixes, trivial looking fixes and to code
- maintained by other developers. We usually have a reason for doing things
- the way we do. Send your changes as patches to the libav-devel mailing
- list, and if the code maintainers say OK, you may commit. This does not
- apply to files you wrote and/or maintain.
- at item
- We refuse source indentation and other cosmetic changes if they are mixed
- with functional changes, such commits will be rejected and removed. Every
- developer has his own indentation style, you should not change it. Of course
- if you (re)write something, you can use your own style, even though we would
- prefer if the indentation throughout Libav was consistent (Many projects
- force a given indentation style - we do not.). If you really need to make
- indentation changes (try to avoid this), separate them strictly from real
- changes.
-
- NOTE: If you had to put if()@{ .. @} over a large (> 5 lines) chunk of code,
- then either do NOT change the indentation of the inner part within (do not
- move it to the right)! or do so in a separate commit
- at item
- Always fill out the commit log message. Describe in a few lines what you
- changed and why. You can refer to mailing list postings if you fix a
- particular bug. Comments such as "fixed!" or "Changed it." are unacceptable.
- at item
- If you apply a patch by someone else, include the name and email address in
- the log message. Since the libav-commits mailing list is publicly
- archived you should add some SPAM protection to the email address. Send an
- answer to libav-devel (or wherever you got the patch from) saying that
- you applied the patch.
+ at item
+ Patches that change behavior of the programs (renaming options etc) or
+ public API or ABI should be discussed in depth and possible few days should
+ pass between discussion and commit.
+ Changes to the build system (Makefiles, configure script) which alter
+ the expected behavior should be considered in the same regard.
@item
When applying patches that have been discussed (at length) on the mailing
list, reference the thread in the log message.
@item
- Do NOT commit to code actively maintained by others without permission.
- Send a patch to libav-devel instead. If no one answers within a reasonable
- timeframe (12h for build failures and security fixes, 3 days small changes,
- 1 week for big patches) then commit your patch if you think it is OK.
- Also note, the maintainer can simply ask for more time to review!
- at item
- Subscribe to the libav-commits mailing list. The diffs of all commits
- are sent there and reviewed by all the other developers. Bugs and possible
- improvements or general questions regarding commits are discussed there. We
- expect you to react if problems with your code are uncovered.
+ Subscribe to the libav-devel and libav-commits mailing list.
+ Bugs and possible improvements or general questions regarding commits
+ are discussed on libav-devel. We expect you to react if problems with
+ your code are uncovered.
@item
Update the documentation if you change behavior or add features. If you are
- unsure how best to do this, send a patch to libav-devel, the documentation
- maintainer(s) will review and commit your stuff.
+ unsure how best to do this, send an [RFC] patch to libav-devel.
@item
- Try to keep important discussions and requests (also) on the public
- developer mailing list, so that all developers can benefit from them.
+ All discussions and decisions should be reported on the public developer
+ mailing list, so that there is a reference to them.
+ Other media (e.g. IRC) should be used for coordination and immediate
+ collaboration.
@item
Never write to unallocated memory, never write over the end of arrays,
always check values read from some untrusted source before using them
- as array index or other risky things.
+ as array index or other risky things. Always use valgrind to doublecheck.
@item
Remember to check if you need to bump versions for the specific libav
parts (libavutil, libavcodec, libavformat) you are changing. You need
@@ -223,13 +207,12 @@ should also be avoided if they don't make the code easier to understand.
Incrementing the third component means a noteworthy binary compatible
change (e.g. encoder bug fix that matters for the decoder).
@item
- Compiler warnings indicate potential bugs or code with bad style. If a type of
- warning always points to correct and clean code, that warning should
- be disabled, not the code changed.
- Thus the remaining warnings can either be bugs or correct code.
+ Compiler warnings indicate potential bugs or code with bad style.
If it is a bug, the bug has to be fixed. If it is not, the code should
be changed to not generate a warning unless that causes a slowdown
or obfuscates the code.
+ If a type of warning leads to too many false positives, that warning
+ should be disabled, not the code changed.
@item
If you add a new file, give it a proper license header. Do not copy and
paste it from a random place, use an existing file as template.
@@ -237,16 +220,15 @@ should also be avoided if they don't make the code easier to understand.
We think our rules are not too hard. If you have comments, contact us.
-Note, these rules are mostly borrowed from the MPlayer project.
+Note, some rules were borrowed from the MPlayer project.
@section Submitting patches
-First, (@pxref{Coding Rules}) above if you did not yet.
-
-When you submit your patch, try to send a unified diff (diff '-up'
-option). We cannot read other diffs :-)
+First, read the (@pxref{Coding Rules}) above if you did not yet, in particular
+the rules regarding patch submission.
-Also please do not submit a patch which contains several unrelated changes.
+As stated already, please do not submit a patch which contains several
+unrelated changes.
Split it into separate, self-contained pieces. This does not mean splitting
file by file. Instead, make the patch as small as possible while still
keeping it as a logical unit that contains an individual change, even
@@ -256,8 +238,8 @@ for us and greatly increases your chances of getting your patch applied.
Use the patcheck tool of Libav to check your patch.
The tool is located in the tools directory.
-Run the regression tests before submitting a patch so that you can
-verify that there are no big problems.
+Run the @pxref{Regression Tests} before submitting a patch in order to verify
+it does not cause unexpected problems.
Patches should be posted as base64 encoded attachments (or any other
encoding which ensures that the patch will not be trashed during
@@ -266,16 +248,20 @@ transmission) to the libav-devel mailing list, see
It also helps quite a bit if you tell us what the patch does (for example
'replaces lrint by lrintf'), and why (for example '*BSD isn't C99 compliant
-and has no lrint()')
+and has no lrint()'). This kind of explanation should be the body of the
+commit message.
Also please if you send several patches, send each patch as a separate mail,
do not attach several unrelated patches to the same mail.
+Use @code{git send-email} when possible since it will properly send patches
+without requiring extra care.
+
Your patch will be reviewed on the mailing list. You will likely be asked
to make some changes and are expected to send in an improved version that
incorporates the requests from the review. This process may go through
-several iterations. Once your patch is deemed good enough, some developer
-will pick it up and commit it to the official Libav tree.
+several iterations. Once your patch is deemed good enough, it will be
+committed to the official Libav tree.
Give us a few days to react. But if some time passes without reaction,
send a reminder by email. Your patch should eventually be dealt with.
@@ -301,8 +287,8 @@ send a reminder by email. Your patch should eventually be dealt with.
even if it is only a decoder?
@item
Did you add a rule to compile the appropriate files in the Makefile?
- Remember to do this even if you're just adding a format to a file that is
- already being compiled by some other rule, like a raw demuxer.
+ Remember to do this even if you are just adding a format to a file that
+ is already being compiled by some other rule, like a raw demuxer.
@item
Did you add an entry to the table of supported formats or codecs in
@file{doc/general.texi}?
@@ -312,7 +298,7 @@ send a reminder by email. Your patch should eventually be dealt with.
If it depends on a parser or a library, did you add that dependency in
configure?
@item
- Did you "git add" the appropriate files before committing?
+ Did you @code{git add} the appropriate files before committing?
@end enumerate
@section patch submission checklist
@@ -323,12 +309,11 @@ send a reminder by email. Your patch should eventually be dealt with.
@item
Does @code{make checkheaders} pass with the patch applied?
@item
- Is the patch a unified diff?
- at item
Is the patch against latest Libav git master branch?
@item
- Are you subscribed to ffmpeg-dev?
- (the list is subscribers only due to spam)
+ Are you subscribed to libav-devel?
+ (@url{https://lists.libav.org/mailman/listinfo/libav-devel}
+ the list is subscribers)
@item
Have you checked that the changes are minimal, so that the same cannot be
achieved with a smaller patch and/or simpler final code?
@@ -344,9 +329,6 @@ send a reminder by email. Your patch should eventually be dealt with.
tools/trasher and the noise bitstream filter. Your decoder or demuxer
should not crash or end in a (near) infinite loop when fed damaged data.
@item
- Is the patch created from the root of the source tree, so it can be
- applied with @code{patch -p0}?
- at item
Does the patch not mix functional and cosmetic changes?
@item
Did you add tabs or trailing whitespace to the code? Both are forbidden.
@@ -381,8 +363,6 @@ send a reminder by email. Your patch should eventually be dealt with.
@item
Lines with similar content should be aligned vertically when doing so
improves readability.
- at item
- Did you provide a suggestion for a clear commit log message?
@end enumerate
@section Patch review process
@@ -401,37 +381,22 @@ After a patch is approved it will be committed to the repository.
We will review all submitted patches, but sometimes we are quite busy so
especially for large patches this can take several weeks.
-When resubmitting patches, please do not make any significant changes
-not related to the comments received during review. Such patches will
-be rejected. Instead, submit significant changes or new features as
-separate patches.
-
- at section Regression tests
-
-Before submitting a patch (or committing to the repository), you should at least
-test that you did not break anything.
+When resubmitting patches, if their size grew or during the review different
+issues arisen please split the patch so each issue has a specific patch.
-The regression tests build a synthetic video stream and a synthetic
-audio stream. These are then encoded and decoded with all codecs or
-formats. The CRC (or MD5) of each generated file is recorded in a
-result file. A 'diff' is launched to compare the reference results and
-the result file. The output is checked immediately after each test
-has run.
+ at anchor{Regression Tests}
+ at section Regression Tests
-The regression tests then go on to test the FFserver code with a
-limited set of streams. It is important that this step runs correctly
-as well.
+Before submitting a patch (or committing to the repository), you should at
+least make sure that it does not break anything.
-Run 'make test' to test all the codecs and formats. Commands like
-'make regtest-mpeg2' can be used to run a single test. By default,
-make will abort if any test fails. To run all tests regardless,
-use make -k. To get a more verbose output, use 'make V=1 test' or
-'make V=2 test'.
+If the code changed has already a test present in FATE you should run it,
+otherwise it is advised to add it.
-Run 'make fulltest' to test all the codecs, formats and FFserver.
+Improvements to codec or demuxer might change the FATE results. Make sure
+to commit the update reference with the change and to explain in the comment
+why the expected result changed.
-[Of course, some patches may change the results of the regression tests. In
-this case, the reference results of the regression tests shall be modified
-accordingly].
+Please refer to @file{doc/fate.txt}.
@bye
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