From: Bello Olamide Date: Wed, 29 Oct 2025 01:18:53 GMT Subject: [Outreachy][Proposal]: Refactor in order to reduce Git’s global state Message-ID: Hello, This is my proposal for the project "Refactor in order to reduce Git’s global state" for the 2025 Outreachy Internship program. Personal Bio: =========== Full Name: Bello Caleb Olamide Email: belkid98@gmail.com Personal Blog: https://cloobtech.hashnode.dev/ GitHub: https://github.com/cloobtech About Me: ========= I'm Bello Olamide. I am passionate about software engineering and I love to figure out things. I like participating in tech events such as hackathons but this will be my first open source experience and I have relished the opportunity and experience so far. I love being part of a community that strive to achieve a goal and one that I found myself is a small albeit growing community that helps to guide and mentor younger boys find their way into the tech ecosystem. I have developed my coding skill via various sources including personal learning, freelancing, collaboration with other developers and from the ALX Software Engineering program. Past Experience with Git: =================== I have been a Git user for sometime now majorly for collaborating with other developers, tracking version changes to files and during this contribution stage, I have understood the ropes of how to send patches to Git. Contributions to the Git Community: ========================== I have been able to send some patches to the Git codebase with the guidance and direction of community members. Microproject: ========== Link: https://lore.kernel.org/git/cover.1761217100.git.belkid98@gmail.com/ Branch: ob/gpg-interface-cleanup Status: Merged to next Commit ID: ce6d041635 Description: strbuf_split*() to split a string into multiple strbufs is often a wrong API to use. A few uses of it have been removed by simplifying the code. Project Overview ============= Git uses a single global `struct repository` object called `the_repository` which internal functions rely on to store, access and modify environment and configuration variables. With this approach, multi-repository instances running in the same process can lead to inconsistent behaviours and race conditions. By refactoring the code to stop storing repository-scoped configurations in global variables in `environment.c file`, that is by moving the appropriate global variables into localised state within the `struct repository` and `struct repo-settings`, the codebase becomes more maintainable, easier to test and future work such as libifying Git becomes feasible. Internship Objectives and Plans ======================== The project aims to identify repository scoped global variables in `environment.c` and related files that can be moved to local scope within `struct repository` and `struct repo-settings`, find an appropriate strategy to move them to local scope and implement the changes. This architectural improvement will make the codebase more maintainable and enable better multi-repository handling in the future. From a high level overview, environment.[ch] exposes some global variables that reflect a per-repository state and examples of such include git_work_tree_cfg, is_bare_repository_cfg, and core.* settings and functions which also depend on `the_repository` such as have_git_dir(), is_bare_repository(). After a brief study of some related work done on the project, it is important to understand the purpose of the identified global variable and how it is used across the code base, observing how it relates with other subsystems and moving it to the `struct repository` or `struct repo-settings` if its use is repository specific, or specify an appropriate context based on its scope and use this context in the accessor functions. For example in [1], Patrick Steinhardt observes that `core.hooksPath` is repository specific and is stored in the global variable `git_hooks_path`. The variable is then moved into local scope in the repo-settings struct and a new accessor function `repo_settings_get_hooks_path()` is written and used to set the `hooks_path` of the repo specific struct which the path subsystem reads from. Similarly in [2], `core.sharedRepository` is tracked via the global variables `the_shared_repository ` and `need_shared_repository`. These are then moved into the repo-settings struct, with new accessors functions written to modify them, and calls to the accessors in the path subsystem are then modified to replace the old accessors which modify the global variables. I also studied [3], [4] by Ayush Chandeker,] and [5] by John Cai to broaden my understanding of the project. Proposed Project Execution Timeline ========================= 1. Study Code Base To Identify Suitable Candidates (Now - December 8, 2025): ------------------------------------------------------------------------ - The first step will be familiarising myself with the code base to understand how these global variables in environment.c are initialised, used and how they interact with other subsystems. 2. Community Feedback Bonding ( December 9 - December 15, 2025): ------------------------------------------------------------ - Discuss environment variables with mentors and community members - Understand best refactoring approach based on feedback from mentors 3. Review Existing Patch and Define Criteria (December 16 - January 9, 2026): ------------------------------------------------------------- - Thoroughly examine the existing patch series submitted to the mailing list to understand; * What criteria makes a global variable a suitable candidate to be moved to the `struct repository` or `struct repo-settings` * What appropriate context it should be moved into based on its interactions with other subsystems. * If remaining a global variable is the best approach in its case. - This information can be gotten by paying attention to the discussions in the patches and also engaging with my mentors and the Git community. 4. Implement Candidates and Submit PRs ( January 10 - February 28, 2026): -------------------------------------------------------------------------- - With collaboration from mentors and the Git community, identify suitable candidates for relocation. - Relocate them into `struct repository`, `struct repo-settings` and other appropriate contexts. - Pass the repository parameter to accessor functions to replace the global dependence - Write new accessor functions if necessary - Modify accessor callers to reflect the new changes while ensuring all affected code paths works correctly - Update tests and documentations - Recursively submit patches for reviews, engaging in discussions and implement suggestions 5. Final Report on Project (February 29 - March 6) -------------------------------- - Document final report in my blog with details on my experience - Finalize any pending tasks or reviews on any submitted patch Availability ======== I am currently not enrolled in any school or jobs, so I will be able to give 30 hours a week or more to make the project a success. Blogging ======= I have set up my blog where i will document my progress, insights, challenges and experience weekly. Post Outreachy ==================== The welcoming and patient atmosphere during this short contribution period with the Git community has made me want to keep getting involved with the community. I am committed to continuously contributing to Git and become a part of of the next set of contributors to champion the continuous development of Git. Appreciation ========== To Junio and Christian, I really appreciate your guidance, patience and direction while reviewing and helping with my patches and to Usman for your inputs and to every member of the Git community, I thank you all. References ========= [1]: https://public-inbox.org/git/20250207-b4-pks-path-drop-the-repository-v2-14-13cad3c11b8a@pks.im/#Z31config.c [2]: https://public-inbox.org/git/20250206-b4-pks-path-drop-the-repository-v1-15-4e77f0313206@pks.im/ [3]: https://lore.kernel.org/git/d0e2042b3061320fac8a8fdf9043c6ab4dbed5a2.1752882401.git.ayu.chandekar@gmail.com/ [4]: https://lore.kernel.org/git/c82620a1f54ea6760bff204fd2b5fe5c2df1896c.1753804956.git.ayu.chandekar@gmail.com/ [5]: https://public-inbox.org/git/pull.1826.git.git.1730926082.gitgitgadget@gmail.com/