From 58427b9a5cf30e30a1f32d57a644283d162fd68b Mon Sep 17 00:00:00 2001 From: native-api Date: Thu, 31 Mar 2022 05:28:28 +0300 Subject: [PATCH] Add CONTRIBUTING.md (#2287) --- CONTRIBUTING.md | 104 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 CONTRIBUTING.md diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md new file mode 100644 index 00000000..ed79a451 --- /dev/null +++ b/CONTRIBUTING.md @@ -0,0 +1,104 @@ +General guidance +================ + +* The usual principes of respecting existing conventions and making sure that your changes + are in line with the overall product design apply when contributing code to Pyenv. + +* We are limited to Bash 3.2 features + + That's because that's the version shipped with MacOS. + (They didn't upgrade past it and switched to Zsh because later versions + are covered by GPLv3 which has additional restrictions unacceptable for Apple.) + +* Be extra careful when submitting logic specific for the Apple Silicon platform + + As of this writing, Github Actions do not support it and only one team member has the necessary hardware. + So we may be unable to test your changes and may have to take your word for it. + + +Formatting PRs +============== + +We strive to keep commit history one-concern-per-commit to keep it meaningful and easy to follow. +If a pull request (PR) addresses a single concern (the typical case), we usually squash commits +from it together when merging so its commit history doesn't matter. +If however a PR addresses multiple separate concerns, each of them should be presented as a separate commit. +Adding multiple new Python releases of the same flavor is okay with either a single or multiple commits. + + +Authoring installation scripts +============================== + +Adding new Python release support +--------------------------------- + +The easiest way to add support for a new Python release is to copy the script from the previous one +and adjust it as necessary. In many cases, just changing version numbers, URLs and hashes is enough. +Do pay attention to other "magic numbers" that may be present in a script -- +e.g. the set of architectures and OS versions supported by a release -- since those change from time to time, too. + +Make sure to also copy any patches for the previous release that still apply to the new one. +Typically, a patch no longer applies if it addresses a problem that's already fixed in the new release. + +For prereleases, we only create an entry for the latest prerelease in a specific version line. +When submitting a newer prerelease, replace the older one. + + +Adding version-specific fixes/patches +------------------------------------- + +We accept fixes to issues in specific Python releases that prevent users from using them with Pyenv. + +In the default configuration for a Python release, we strive to provide as close to vanilla experience as practical, +to maintain [the principle of the least surprise](https://en.wikipedia.org/wiki/Principle_of_least_astonishment). +As such, any such fixes: + +* Must not break or degrade (e.g. disable features) the build in any of the environments that the release officially supports +* Must not introduce incompatibilities with the vanilla release (including binary incompatibilities) +* Should not patch things unnecessarily, to minimize the risk of the aforementioned undesirable side effects. + * E.g. if the fix is for a specific environment, its logic ought to only fire in this specific environment and not touch execution paths for other environments. + * As such, it's advisable to briefly explain in the PR what each added patch does and why it is necessary to fix the declared problem + +Generally, version-specific fixes belong in the scripts for the affected releases and/or patches for them -- this guarantees that their effect is limited to only those releases. + +

Backporting upstream patches

+ +Usually, this is the easiest way to backport a fix for a problem that is fixed in a newer release. + +* Clone Python, check out the tag for the appropriate release and create a branch +* Apply existing patches if there are any (with either `patch` or `git am`) and commit +* Cherry-pick the upstream commit that fixes the problem in a newer release +* Commit and `git format-patch` +* Commit the generated patch file into Pyenv, test your changes and submit a PR + + +Deprecation policy +------------------ + +We do not provide official support for EOL releases and environments or otherwise provide any kind of extended support for old Python releases. + +We do however accept fixes from interested parties that would allow running older, including EOL, releases in newer environments. +In addition to the above general requirements for release-specific fixes, + +* Such a fix must not add maintenance burden (e.g. add new logic to `python-build` that has to be kept there indefinitely) + * Unless the added logic is useful for both EOL and non-EOL releases. In this case, it will be considered as being primarily an improvement for non-EOL releases. +* We do not provide any guarantees from our side that any such fix works or will continue working going forward. It's up to the interested parties to maintain it. + + +Advanced changes / adding new Python flavor support +--------------------------------------------------- + +An installation script is sourced from `python-build`. All installation scripts are based on the same logic: + +1. Select the source to download and other variable parameters as needed. + + This includes showing an error if the user's environment (OS, architecture) is not supported by the release. + Binary releases that only officially support specific distro(s) typically show a warning in other distros instead. + +2. Run one of the `install_*` shell functions + +`install_*` shell functions defined in `python-build` install Python from different kinds of sources -- compressed package (binary or source), upstream installation script, VCS checkout. Pick one that's the most appropriate for your packaging. + +Each of them accepts a couple of function-specific arguments which are followed by arguments that constitute the build sequence. Each `` in the build sequence corresponds to the `install_*_` function in `python-build`. Check what's available and add any functions with logic specific to your flavor if needed. + +We strive to keep out of `python-build` parts of build logic that are release-specific and/or tend to change abruptly between releases -- e.g. sets of supported architectures and other software's versions. This results in logic duplication between installation scripts -- but since old releases never change once released, this doesn't really add to the maintenance burden. As a rule of thumb, `python-build` can host parts of logic that are expected to stay the same for an indefinite amount of time -- for an entire Python flavor or release line.