Core Platform Team/Initiatives/Quantify and reduce coupling in MediaWiki Core
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Quantify and reduce coupling in MediaWiki Core
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Initiative Description
- Summary
This project aims to improve the modularity of the MediaWiki code base by reducing instances of tight coupling, with a focus on removing cyclic dependencies between components.
- Significance and Motivation
Small components with well defined interfaces are easier to understand and maintain than large complex components. Tight coupling between components, especially if circular, means that the two components behave as one, and cannot be understood or modified independently.
By removing coupling, we allow code to be put in a library. This makes future coupling impossible since it is no longer in the code base. It also makes our code usable in other projects outside of MediaWiki.
Having smaller components that can be understood and maintained separately means it becomes easier to modify the software, easier to find bugs, and easier to train new engineers to work on the software. All of these factors contribute to the goal of delivering improvements to our users more quickly.
Current investigation is ongoing here:
https://docs.google.com/document/d/1hC4sYLsVN0bAVUHkCDPSk-RAjK6_2IYM_GBOjKmkk-M/edit#
This project is likely to be scoped into smaller projects which are focused on specific parts of the code base.
- Outcomes
Architect our code, services and infrastructure for change and sustainability
- Baseline Metrics
TBD
- Target Metrics
TBD
- Stakeholders
Extension developers
Core code developers
- Known Dependencies/Blockers
Adding API integration tests
Architecture Principles
Epics, User Stories, and Requirements
- Perform analysis of tools for measuring coupling
- Detect and analyze cyclic dependencies (use phpda)
- Measure code abstraction and instability (use pdepend or phpmetrics)
- Set up tools for continuous measurements over time
- Analyze codebase to identify the first areas to decouple
- Set baseline and target metric for decoupling
- Refactor code to remove tight coupling in first areas
- Reanalyze codebase to see next steps
Time and Resource Estimates
- Estimated Start Date
March 2019
- Actual Start Date
None given
- Estimated Completion Date
None given
- Actual Completion Date
None given
- Resource Estimates
None given
- Collaborators
Core Platform
Open Questions
- What is a reasonable metric and acceptable target for this project?
Documentation Links
- Phabricator
https://phabricator.wikimedia.org/project/manage/3729/
- Plans/RFCs
https://docs.google.com/document/d/16NwfSJuj7fc2da1fOJM_sqKMdioHN1qPQavydGLDxic/edit
- Other Documents
None given