CONTRIBUTING.md

Guidelines for code development, structure, formating etc.

The CORSIKA Project very much welcomes contributions. Here we outlined how you can find the right place to contribute, and how to do that. Connect to http://gitlab.ikp.kit.edu and corsika-devel@lists.kit.edu or corsika-project@lists.kit.edu to get in touch with the project. The CORSIKA Project decides on the GUIDELINES, and can change them.

How to contribute

• We organize all development via Issues that may be feature requests, ideas, or bugs fix requests.
• New issues can be created, or existing issues picked up.
• Issues are discussed in meetings or via corsika-devel@lists.kit.edu within the CORSIKA Project.
• Issues are assigned to milestones.
• The work on issues is performed in branches that can be best created directly via the gitlab web interface.
• Proposed code to close one issue (located in a specific git branch) is reviewed and eventually discussed, and finally merged into the master branch to close the issue.

Code formatting

We rely on clang-format for code formatting. This has the tremendous advantage that definitely all code follows the same formatting rules, and nobody at any point needs to invest time and effort into code formatting. We provide a script do-clang-format.sh, which can be very useful. But we urge everybody to integrate clang-format already on the level of your source code editor. See the official page for information about clang-format and its editor integration.

The definition of source code format is written down in the file .clang-format and can be changed, if the CORSIKA Project agrees on it. To see what is possible, check e.g. link1 or link2.

Naming conventions

While clang-format does the structural formatting, we still need to agree on naming conventions:

• Classes and structs start with capital letters

• Class member variables start with "f"

• Any static variable has a "g" prefix. A static member variable starts with "fg"

• Class member functions start with capital letters

• Any class getter begins with "Get", and setter with "Set"

• enums should be "enum class", and start with a capital "E", enum entries start with "e"

• We use namespaces to avoid clashes and to structure code

  • Everything is part of the corsika namespace
  • All classes and objects are encapsulated into suited sub-namespaces, thus corsika::geometry, corsika::processes, corsika::units, etc.
  • Namespace names do not use capital letters.
  • Every header file is copied during build and install into "include/corsika/[namespace]" which also means, each header file can only provide definitions for a single namespace. It is one main purpose of namespaces to structure the location of header files.
  • Each header file uses an include protection that includes at least the namespace name, and header file name, thus, #ifndef __include_geometry_Point_h__ or #ifnedf __geometry_Point_h__, or similar are acceptable.
  • Header files should always be included with <..>, thus, #include <corsika/geometry/Point.h> since the build system will always provide the correct include directives (and files anyway cannot be found in file-system paths that typically do not follow the namespace naming conventions outlined here).

• Header files are named after the main class (or object) they define. This also means each header file name starts with a capital letter.

Coding rules

• Code may not introduce any compiler errors, or warnings
• All unit tests must succeed at all times
• We use C++17 concepts wherever useful and helpful
• On any major error or malfunction we throw an exception. This is needed and required for complex physics and shower debugging.
• We never catch exceptions for error handling, there might be very few special exceptions from this. We need to discuss such cases.
• Everything that should not change should be const
• Everything that does not need to be visible to the outside of a class/struct should be private or protected
• We prefer the use of references, wherever useful
• There cannot be any pointer in the interface of any class or object exposed to outside users, there might be pointers for very special cases inside of classes.
• When you contribute new code, or extend existing code, at the same time provide unit-tests for all functionality.
• Code must be documented with doxygen commands

Release versioning scheme

Releases of CORSIKA are thought to be the baseline for larger scale testing, and full production. The releases are numbered as x.y.z, starting with x=8 form the gitlab c++ version. X will only be incremented for major design or physics changes. The y index is updated for new official releases that normally contain improved or enhanced physics performance, and may also contain normal interface changes to accomodate improvements. The z index can be updated frequently for bug fixes or new features. Changes in z will not contain interface changes, thus, code will remain fully compatible.
Special releases of CORSIKA can also have a tag name from git, e.g. as in the "milestone1" release.

How to become scientific author of the CORSIKA Project

The CORSIKA Project decides on who becomes scientific author. The following conditions are clearly sufficient, but not all of them are required all the time:

• responsibility for a particular functionality or part
• follows these GUIDELINES
• agrees to the COLLABORATION_AGREEMENT
• active in the CORSIKA Project, that means responsive to discussions and problems in corsika-devel@list.kit.edu or on https//gitlab.ikp.kit.edu, of relevant issues, or in (phone) meetings
• the members of the CORSIKA Project panel agree