Coding Standards

Repository and Versioning Conventions


The following roles are standardized in our repository and release management:

  • Lead: The individual in charge of the department or a project. (Lead roles and hierarchy are defined in the MousePaw Media Employee Handbook, and are beyond the scope of this document.)

  • Repository Master: A trained individual who is granted administrative control of the repositories and build system, and who is entrusted with deciding if and when to commit to protected branches.

  • Trusted developer: All staff members, as well as any open source contributors who have been explicitly granted trust privileges by a staff member.


We reserve and protect three branches in our Git repositories:

  • devel is for the latest development version.

  • fresh is for the latest testing release.

  • stable is for the latest stable release.

Any developer can push to devel with an approved code review from a Trusted developer. However, only a Repository Master can push directly to devel.

A Repository Master is the only individual who can push to fresh or stable, and thus must be the one to land (commit) any code which passes code review.


Starting from January 2020, we use Semantic Versioning for all software development projects. Our version numbers follow the format X.Y.Z

  • X is a major release, reserved for changes to the API or CLI.

  • Y is a minor release, for releases with new features.

  • Z is a patch release, for bugfix-only releases.


Fixing a bug in a non-released version does not qualify for a patch release number! For example, if a bug is fixed in 2.4.0-beta2, a bugfix would create 2.4.0-beta3, and not 2.4.1-beta3.

About Zero-Versions

Zero-Versions are versions at Major Release 0. They are considered inherently unstable and feature incomplete, and thereby un-releasable. They cannot be promoted to either fresh or stable.

A project remains at a Zero-Version until it is considered complete and stable enough to promote to ALPHA. The Major version remains at 0, but the Minor and Bugfix versions can be incremented at the discretion of the Lead and Repository Master.

When a version is deemed complete and stable enough to promote to an ALPHA, the version number immediately jumps from 0.N.N to 1.0.0-alpha.N, and only N is incremented.

ALPHA Versions

ALPHA versions are committed to the devel branch. They are generally feature-frozen, and represent candidates for promotion to fresh.

In versioning, -alpha.N` is amended for ALPHA-versions, where ``N is the ALPHA version number. For example, in preparation for release of 2.4.0, the first candidate of the development code for promotion to fresh would be version 2.4.0-alpha.1, and should be tagged as such.

If an additional feature is to be added to an ALPHA, it is kicked back down to a Development version, and the ALPHA suffix is dropped. If it was promoted to 1.0.0-alpha.N from a Zero-Version, it will be reverted to the next appropriate Zero-Version until the feature is considered stable enough to warrent another ALPHA Release.


Determine ALPHA candidacy/testing standards.

BETA Versions

BETA versions are committed to the fresh branch. They are feature-frozen, and are intended for testing, but are not yet considered stable enough to be a “release candidate”.

In versioning, -betaN is amended for BETA-versions, where N is the BETA version number. For example, after 2.4.0 is first promoted to the fresh branch, it would be tagged 2.4.0-beta.1.

Additional features may not be added to a BETA. Once a version is promoted from an ALPHA to a BETA, it should be considered feature-frozen, for better or for worse. If the feature is considered to be a blocking feature to the Release, the Release cycle should be abandoned, and the version kicked back down to a development version on devel . It will then gain a new Minor release number before it is promoted to ALPHA and BETA again.


Determine BETA candidacy/testing standards.

Release Candidates

When a BETA version is believed to be stable enough for release, it would be promoted to a Release Candidate (RC). It would remain in fresh, but would be considered a candidate for release to stable.

In versioning, -rcN is amended for RC-versions, where N is the Release Candidate number. For example, if 2.4.0-beta.6 is believed to be stable after field testing, it should be promoted to 2.4.0-rc.1.

A Release Candidate is feature-frozen in the exact same manner as a BETA. However, if a Release cycle is abandoned due to a missing feature, the candidacy and testing processes should be audited.


Determine RC candidacy/testing standards.


Once a Release Candidate is confirmed to be stable enough for release, it should be promoted to stable, and the suffix dropped, leaving only the X.Y.Z version.

If a Lead Developer or Repository Master believes a Major or Minor Release is stable enough to skip the ALPHA or BETA phase, they may do so. However, all major and minor releases should always be tested at Release Candidate phase before final release.

Patch Releases can be expedited directly to Release Candidate or Release phase by a Lead Developer or Repository Master. Care should be taken in making this call, however, as some bugfixes can break other things.


Determine Release candidacy/testing standards.

Build Numbers

If build numbers needed, such as during Debian packaging, the build number may be appended to the version in the format +YYYYMMDDHHMMSS, where YYYY is the year, MM is the two-digit month number, DD is the two-digit day number, HH is the two-digit hour in military time UTC, and MM and SS are the two-digit minute and second respectively.

The build metadata and script files are considered part of the project, and are versioned as Patch releases. Assuming the build metadata and script files are unchanged, the build itself should never increment the build; in that case, only the build number should be updated.

C and C++

File Types

  • C++

    • Headers: .hpp

    • Implementation: .cpp

  • C

    • Headers: .h

    • Implementation: .c

The reason behind this is so we can use C and C++ in parallel with one another, without confusing what language any given file is written in.

Naming Conventions

  • Variables: lower_snake_case


  • Functions: lower_snake_case

  • Classes: UpperCamelCase

  • Filenames: lower_snake_case



We are currently debating whether to switch to OTBS.

  • Use Allman bracketing and indentation style.

if (x == y)
  • Avoid code beyond 80 characters. Never exceed 120 characters.

  • Indentation should use tab characters (4 space width), with spaces for further alignment.

  • A switch’s block should be indented, and each case’s block should be indented in the same manner.

  • Line up lists so a) the start of list item lines align, and b) the end of list item lines roughly align. Each line should end with either a comma or, in the case of the last line, the closing token.

string names[9] = {"Bob", "Fred", "Jim",
                   "Chris", "Dave", "Jack",
                   "Ozymandius", "Randall",
  • Pointer and reference indicators * and & should be aligned to the type part of the statement, not the name.

  • Insert space padding around operators.

  • Insert space padding after parenthesis headers (after if, switch, etc.)

  • One-line blocks (i.e. one line if statements) should still have brackets.


  • Use CSI Commenting Standard.

    • All functions and variables should have a doc comment at declaration.

    • CSI comment every logical block.

    • Header files and standalone implementation files should always have CSI-style description and license comments at the top.

  • Use // and /* ... */ for CSI comments.

  • When a comment spans multiple lines, prefer multiline /* ... */ comments. We recommend using line-leading ``* ``.

/* This is a multiline comment
 * that spans multiple lines.
 * See how nice this looks?
  • Use /// and /** ... */ for doc comments.

    • Each parameter description in doc comments should be preceded by \param on a new line.

    • The return description in doc comments should be preceded by \return on a new line.

  • Do not commit commented out code.

  • Avoid inline comments whenever possible.

  • Use //TODO, //NOTE, and //FIXME notation where necessary.


  • main.c and main.cpp should reside in the root directory.

  • .h and .hpp files should be in an the include/ directory. For libraries, header files should be in a <project> subfolder (i.e. include/anari/ or include/pawlib/).

  • .c and .cpp files should be in the src/ directory.

  • Documentation files should be in the docs/ directory.


Based on PEP8 and PEP257.

Naming Conventions

  • Variables: lower_snake_case


  • Functions: lower_snake_case

  • Classes: UpperCamelCase

  • Filenames/Modules: lower_snake_case (Underscores discouraged, however. Avoid when possible.)


  • Four-space indentation ONLY.

  • Avoid code beyond 80 characters. Use \ as necessary to break lines. Never exceed 120 characters.

  • Line up multi-line structures as follows, with the opening and closing brackets on separate lines, and the start of the items lined up. Each item may be on its own line, but this is not required.

names = [
    "Bob", "Fred", "Jim",
    "Chris", "Dave", "Jack",
    "Ozymandius", "Randall",


  • Include docstrings for all functions, classes, and modules, following PEP257

  • Please avoid inline comments. Comment above lines.

  • Use single line comments when possible. (#)

  • Please comply with the CSI Commenting Standard as much as possible.

  • Use #TODO, #NOTE, and #FIXME notation where necessary.

  • All files should precede with CSI-style description docstrings and license comments.

  • Do not commit commented out code.

Python Code Formatter

black should be used as the code formatter.