10 KiB
Outline of the GitHub Development Workflow
This purpose of this document is to provide a point of reference for the core LAMMPS developers and other LAMMPS contributors to understand the choices the LAMMPS developers have agreed on. Git and GitHub provide the tools, but do not set policies, so it is up to the developers to come to an agreement as to how to define and interpret policies. This document is likely to change as our experiences and needs change and we try to adapt accordingly. Last change 2018-12-19.
Table of Contents
GitHub Merge Management
In the interest of consistency, ONLY ONE of the core LAMMPS developers should doing the merging itself. This is currently @akohlmey (Axel Kohlmeyer). If this assignment needs to be changed, it shall be done right after a stable release. If the currently assigned developer cannot merge outstanding pull requests in a timely manner, or in other extenuating circumstances, other core LAMMPS developers with merge rights can merge pull requests, when necessary.
Pull Requests
ALL changes to the LAMMPS code and documentation, however trivial, MUST be submitted as a pull request to GitHub. All changes to the "master" branch must be made exclusively through merging pull requests. The "unstable" and "stable" branches, respectively are only to be updated upon patch or stable releases with fast-forward merges based on the associated tags. Pull requests may also be submitted to (long-running) feature branches created by LAMMPS developers inside the LAMMPS project, if needed. Those are not subject to the merge and review restrictions discussed in this document, though, but get managed as needed on a case-by-case basis.
Pull Request Assignments
Pull requests can be "chaperoned" by one of the LAMMPS core developers.
This is indicated by who the pull request is assigned to. LAMMPS core
developers can self-assign or they can decide to assign a pull request
to a different LAMMPS developer. Being assigned to a pull request means,
that this pull request may need some work and the assignee is tasked to
determine whether this might be needed or not, and may either implement
the required changes or ask the submitter of the pull request to implement
them. Even though, all LAMMPS developers may have write access to pull
requests (if enabled by the submitter, which is the default), only the
submitter or the assignee of a pull request may do so. During this
period the work_in_progress
label shall be applied to the pull
request. The assignee gets to decide what happens to the pull request
next, e.g. whether it should be assigned to a different developer for
additional checks and changes, or is recommended to be merged. Removing
the work_in_progress
label and assigning the pull request to the
developer tasked with merging signals that a pull request is ready to be
merged.
Pull Request Reviews
People can be assigned to review a pull request in two ways:
- They can be assigned manually to review a pull request by the submitter or a LAMMPS developer
- They can be automatically assigned, because a developers matches
a file pattern in the
.github/CODEOWNERS
file, which associates developers with the code they contributed and maintain.
Reviewers are requested to state their appraisal of the proposed changes and either approve or request changes. People may unassign themselves from review, if they feel not competent about the changes proposed. At least two approvals from LAMMPS developers with write access are required before merging in addition to the automated compilation tests. Merging counts as implicit approval, so does submission of a pull request (by a LAMMPS developer). So the person doing the merge may not also submit an approving review. The feature, that reviews from code owners are "hard" reviews (i.e. they must all be approved before merging is allowed), is currently disabled and it is in the discretion of the merge maintainer to assess when a sufficient degree of approval, especially from external contributors, has been reached in these cases. Reviews may be (automatically) dismissed, when the reviewed code has been changed, and then approval is required a second time.
Pull Request Discussions
All discussions about a pull request should be kept as much as possible on the pull request discussion page on GitHub, so that other developers can later review the entire discussion after the fact and understand the rationale behind choices made. Exceptions to this policy are technical discussions, that are centered on tools or policies themselves (git, github, c++) rather than on the content of the pull request.
Checklist for Pull Requests
Here are some items to check:
- source and text files should not have CR/LF line endings (use dos2unix to remove)
- every new command or style should have documentation. The names of
source files (c++ and manual) should follow the name of the style.
(example:
src/fix_nve.cpp
,src/fix_nve.h
forfix nve
command, implementing the classFixNVE
, documented indoc/src/fix_nve.txt
) - all new style names should be lower case, the must be no dashes, blanks, or underscores separating words, only forward slashes.
- new style docs should be added to the "overview" files in
doc/src/Commands_*.txt
,doc/src/{fixes,computes,pairs,bonds,...}.txt
anddoc/src/lammps.book
- check whether manual cleanly translates with
make html
andmake pdf
- check spelling of manual with
make spelling
in doc folder - new source files in packages should be added to
src/.gitignore
- removed or renamed files in packages should be added to
src/Purge.list
- C++ source files should use C++ style include files for accessing
C-library APIs, e.g.
#include <cstdlib>
instead of#include <stdlib.h>
. And they should use angular brackets instead of double quotes. Full list:- assert.h -> cassert
- ctype.h -> cctype
- errno.h -> cerrno
- float.h -> cfloat
- limits.h -> climits
- math.h -> cmath
- complex.h -> complex
- setjmp.h -> csetjmp
- signal.h -> csignal
- stddef.h -> cstddef
- stdint.h -> cstdint
- stdio.h -> cstdio
- stdlib.h -> cstdlib
- string.h -> cstring
- time.h -> ctime
- Do NOT replace (as they are C++-11):
inttypes.h
andstdint.h
.
- Code should follow the C++-98 standard. C++-11 is only accepted in individual special purpose packages
- indentation is 2 spaces per level
- there should be NO tabs and no trailing whitespace
- header files, especially of new styles, should not include any other headers, except the header with the base class or cstdio. Forward declarations should be used instead when possible.
- iostreams should be avoided. LAMMPS uses stdio from the C-library.
- use of STL in headers and class definitions should be avoided.
- there MUST NOT be any "using namespace XXX;" statements in headers.
- static class members should be avoided at all cost.
- anything storing atom IDs should be using
tagint
and notint
. This can be flagged by the compiler only for pointers and only when compiling LAMMPS with-DLAMMPS_BIGBIG
. - when including both
lmptype.h
(and using defines or macros from it) andmpi.h
,lmptype.h
must be included first. - when pair styles are added, check if settings for flags like
single_enable
,writedata
,reinitflag
,manybody_flag
and others are correctly set and supported.
GitHub Issues
The GitHub issue tracker is the location where the LAMMPS developers
and other contributors or LAMMPS users can report issues or bugs with
the LAMMPS code or request new features to be added. Feature requests
are usually indicated by a [Feature Request]
marker in the subject.
Issues are assigned to a person, if this person is working on this
feature or working to resolve an issue. Issues that have nobody working
on them at the moment, have the label volunteer needed
attached.
When an issue, say #125
is resolved by a specific pull request,
the comment for the pull request shall contain the text closes #125
or fixes #125
, so that the issue is automatically deleted when
the pull request is merged.
Milestones and Release Planning
LAMMPS uses a continuous release development model with incremental
changes, i.e. significant effort is made - including automated pre-merge
testing - that the code in the branch "master" does not get broken.
More extensive testing (including regression testing) is performed after
code is merged to the "master" branch. There are patch releases of
LAMMPS every 1-3 weeks at a point, when the LAMMPS developers feel, that
a sufficient amount of changes have happened, and the post-merge testing
has been successful. These patch releases are marked with a
patch_<version date>
tag and the "unstable" branch follows only these
versions (and thus is always supposed to be of production quality,
unlike "master", which may be temporary broken, in the case of larger
change sets or unexpected incompatibilities or side effects.
About 3-4 times each year, there are going to be "stable" releases of LAMMPS. These have seen additional, manual testing and review of results from testing with instrumented code and static code analysis. Also, in the last 2-3 patch releases before a stable release are "release candidate" versions which only contain bugfixes and documentation updates. For release planning and the information of code contributors, issues and pull requests being actively worked on are assigned a "milestone", which corresponds to the next stable release or the stable release after that, with a tentative release date.