atlassian-labs/atlaspack
Jun 2025 – Oct 2025
5 Months active
Languages Used
JavaScriptRustTypeScriptJSONJSON5Shell
Technical Skills
Build ToolsBundlingCode RefactoringEnvironment VariablesFeature FlagsFull Stack Development
Marcin Szczepanski
PROFILE
Marcin Szczepanski
Michał Szczepański contributed to the atlassian-labs/atlaspack repository by developing advanced build tooling and infrastructure features that improved reliability, maintainability, and performance. He engineered solutions such as a Rust-based SWC transformer for design tokens, granular entry filtering, and robust feature flag management, addressing both code quality and developer experience. Michał applied TypeScript, Rust, and JavaScript to implement integration tests, optimize bundling, and enforce type safety, while also automating code hygiene with cross-language scripts. His work demonstrated depth in backend and build system engineering, resulting in streamlined workflows, safer deployments, and a more maintainable codebase for future development.
Overall Statistics
Feature vs Bugs
83%Features
Repository Contributions
32Total
Bugs
3
Commits
32
Features
15
Lines of code
7,251
Activity Months5
Your Network
75 people
Work History
October 2025
5 Commits • 3 Features
Oct 1, 2025October 2025 monthly summary — atlaspack (atlassian-labs/atlaspack) Key features delivered - Atlaspack Design Tokens Transformer: Introduced @atlaspack/transformer-tokens plugin and a Rust-based SWC transformer to process Atlaskit design tokens, replacing direct token values with CSS custom properties. Includes testing and configuration. Commits: 9cd9521978f783046e2ae4ce78f2de7aeb07d073; 01868d0116693b7e80b5f7d3ba9fd3d21934525c. - Unused Feature Flags Auditor: New script to identify and report unused feature flags across TypeScript, JavaScript, and Rust to improve code hygiene by flagging flags that are defined but not actively used, excluding example flags. Commit: 35ebc72b13eb3ebf310d2184dc1ae1b54e915416. - Workspace Configuration Standardization and Performance Improvements: Standardizes Rust edition to 2024 across the workspace and defers configuration schema validation source loading behind a feature flag to improve startup performance. Commits: 4610eba89269e91fa980711cfdf9cd291e0e5062; 5776be21f70a3f2b9471ba33da3ba1a883f21f1a. Major bugs fixed - Fix invalidation for tokens transformer (#850) (included with transformer work) Overall impact and accomplishments - Streamlined design-token processing and theming by introducing a reusable transformer and CSS variable output, reducing runtime token handling to a lightweight, maintainable pipeline. - Improved startup performance and reliability through workspace-wide Rust edition standardization and deferred config validation loading. - Enhanced code hygiene and governance with an automated audit for unused feature flags across TS/JS/Rust, reducing dead code and flags. - Strengthened build and tooling consistency across the atlaspack workspace, easing onboarding and future contributions. Technologies/skills demonstrated - Rust and SWC-based tooling, TypeScript/JavaScript tooling, cross-language automation, configuration management, performance optimization, testing, and code hygiene governance.
5 Commits • 3 Features
Oct 1, 2025October 2025 monthly summary — atlaspack (atlassian-labs/atlaspack) Key features delivered - Atlaspack Design Tokens Transformer: Introduced @atlaspack/transformer-tokens plugin and a Rust-based SWC transformer to process Atlaskit design tokens, replacing direct token values with CSS custom properties. Includes testing and configuration. Commits: 9cd9521978f783046e2ae4ce78f2de7aeb07d073; 01868d0116693b7e80b5f7d3ba9fd3d21934525c. - Unused Feature Flags Auditor: New script to identify and report unused feature flags across TypeScript, JavaScript, and Rust to improve code hygiene by flagging flags that are defined but not actively used, excluding example flags. Commit: 35ebc72b13eb3ebf310d2184dc1ae1b54e915416. - Workspace Configuration Standardization and Performance Improvements: Standardizes Rust edition to 2024 across the workspace and defers configuration schema validation source loading behind a feature flag to improve startup performance. Commits: 4610eba89269e91fa980711cfdf9cd291e0e5062; 5776be21f70a3f2b9471ba33da3ba1a883f21f1a. Major bugs fixed - Fix invalidation for tokens transformer (#850) (included with transformer work) Overall impact and accomplishments - Streamlined design-token processing and theming by introducing a reusable transformer and CSS variable output, reducing runtime token handling to a lightweight, maintainable pipeline. - Improved startup performance and reliability through workspace-wide Rust edition standardization and deferred config validation loading. - Enhanced code hygiene and governance with an automated audit for unused feature flags across TS/JS/Rust, reducing dead code and flags. - Strengthened build and tooling consistency across the atlaspack workspace, easing onboarding and future contributions. Technologies/skills demonstrated - Rust and SWC-based tooling, TypeScript/JavaScript tooling, cross-language automation, configuration management, performance optimization, testing, and code hygiene governance.
October 2025
September 2025
7 Commits • 5 Features
Sep 1, 2025Summary for 2025-09 (atlassian-labs/atlaspack): - Key features delivered: • Granular Target Entry Filtering: Introduced allowExplicitTargetEntries feature flag to enable per-target entry filtering and produce distinct build outputs for different input subsets. Commit: 038e87a7858d39556d59d3a2d17db534d45f62c6. • Per-Target Custom Environment Variables: Added per-target custom environment variables with a feature flag (customEnvInTargets) to control availability, enabling target-specific configuration. Commit: f6532d7a4f7f007bd4e5e36af04dd466f0b9f572. • Preserve Unstable Single-File CSS Output: Added preserveUnstableSingleFileOutputInCss feature flag to control preserving unstableSingleFileOutput during CSS transformation for better asset handling. Commit: 7a52bab6281e8edbfa66af248eb6f872c6b4b7bd. - Major bugs fixed: • Remove customEnvInTargets flag and cleanup: Removed per-target custom environment variables flag and related logic to simplify feature flag management and reduce unused code. Commit: f1070ec48e99b4ec111a03179c5ab5b74163fab1. • Robust tsconfig.json parsing and error reporting: Enhanced tsconfig.json parsing robustness by adding json5 support and improving error messages for loading/parsing; updates dependencies. Commit: 0a79c1763b7d7aebee6c6389a4f08fd34ca8ac88. • AST-based linting for TS reference update script: Added AST-based linting to the TypeScript reference update script to improve code quality and consistency. Commit: 74ddbe3329571ea3827d20b1138725c9ad0f5163. - Overall impact and accomplishments: Enabled more granular and efficient builds, improved asset handling for CSS transformations, reduced feature-flag complexity, and strengthened code quality and error reporting. These changes enhance reproducibility of builds, speed for targeted releases, and maintainability of the atlaspack codebase. - Technologies/skills demonstrated: TypeScript, AST-based linting, json5 parsing integration, feature-flag governance, ESLint enhancements, and robust error messaging.
September 2025
7 Commits • 5 Features
Sep 1, 2025Summary for 2025-09 (atlassian-labs/atlaspack): - Key features delivered: • Granular Target Entry Filtering: Introduced allowExplicitTargetEntries feature flag to enable per-target entry filtering and produce distinct build outputs for different input subsets. Commit: 038e87a7858d39556d59d3a2d17db534d45f62c6. • Per-Target Custom Environment Variables: Added per-target custom environment variables with a feature flag (customEnvInTargets) to control availability, enabling target-specific configuration. Commit: f6532d7a4f7f007bd4e5e36af04dd466f0b9f572. • Preserve Unstable Single-File CSS Output: Added preserveUnstableSingleFileOutputInCss feature flag to control preserving unstableSingleFileOutput during CSS transformation for better asset handling. Commit: 7a52bab6281e8edbfa66af248eb6f872c6b4b7bd. - Major bugs fixed: • Remove customEnvInTargets flag and cleanup: Removed per-target custom environment variables flag and related logic to simplify feature flag management and reduce unused code. Commit: f1070ec48e99b4ec111a03179c5ab5b74163fab1. • Robust tsconfig.json parsing and error reporting: Enhanced tsconfig.json parsing robustness by adding json5 support and improving error messages for loading/parsing; updates dependencies. Commit: 0a79c1763b7d7aebee6c6389a4f08fd34ca8ac88. • AST-based linting for TS reference update script: Added AST-based linting to the TypeScript reference update script to improve code quality and consistency. Commit: 74ddbe3329571ea3827d20b1138725c9ad0f5163. - Overall impact and accomplishments: Enabled more granular and efficient builds, improved asset handling for CSS transformations, reduced feature-flag complexity, and strengthened code quality and error reporting. These changes enhance reproducibility of builds, speed for targeted releases, and maintainability of the atlaspack codebase. - Technologies/skills demonstrated: TypeScript, AST-based linting, json5 parsing integration, feature-flag governance, ESLint enhancements, and robust error messaging.
August 2025
7 Commits • 3 Features
Aug 1, 2025August 2025: Focused on delivering secure, scalable feature capabilities and improving type safety and build stability across atlaspack. Key accomplishments include feature delivery for inline isolated scripts, macOS cache-watching stability improvements in tests, TypeScript strictness enforcement with noImplicitAny, and introducing stable naming for single-file bundles with an integration test. These work items reduce risk, enhance performance, and improve developer productivity.
7 Commits • 3 Features
Aug 1, 2025August 2025: Focused on delivering secure, scalable feature capabilities and improving type safety and build stability across atlaspack. Key accomplishments include feature delivery for inline isolated scripts, macOS cache-watching stability improvements in tests, TypeScript strictness enforcement with noImplicitAny, and introducing stable naming for single-file bundles with an integration test. These work items reduce risk, enhance performance, and improve developer productivity.
August 2025
July 2025
8 Commits • 2 Features
Jul 1, 2025July 2025 monthly summary for atlassian-labs/atlaspack: Strengthened test infrastructure for reliability and delivered a robust Atlaspack V3 clean shutdown workflow. These efforts improved CI stability, reduced flaky tests, and provided a safer shutdown path for V3 deployments.
July 2025
8 Commits • 2 Features
Jul 1, 2025July 2025 monthly summary for atlassian-labs/atlaspack: Strengthened test infrastructure for reliability and delivered a robust Atlaspack V3 clean shutdown workflow. These efforts improved CI stability, reduced flaky tests, and provided a safer shutdown path for V3 deployments.
June 2025
5 Commits • 2 Features
Jun 1, 2025June 2025: Atlaspack delivered notable bundling reliability improvements and streamlined development workflow. Key features include robust Constant Module Inlining and MSB Bundling Optimization with added integration tests, plus targeted dev-tooling cleanup. Major fixes addressed MSB inclusion of constant modules and scope hoisting/inline constant issues, reducing build failures and improving performance. The changes reduce maintenance burden through codebase cleanup and removal of unused features. Business impact includes more predictable, faster builds, smoother onboarding for new developers, and reduced risk in production bundles. Technologies and skills demonstrated span JavaScript/Node tooling, module graph analysis, integration testing, Babel tooling, and private package references.
5 Commits • 2 Features
Jun 1, 2025June 2025: Atlaspack delivered notable bundling reliability improvements and streamlined development workflow. Key features include robust Constant Module Inlining and MSB Bundling Optimization with added integration tests, plus targeted dev-tooling cleanup. Major fixes addressed MSB inclusion of constant modules and scope hoisting/inline constant issues, reducing build failures and improving performance. The changes reduce maintenance burden through codebase cleanup and removal of unused features. Business impact includes more predictable, faster builds, smoother onboarding for new developers, and reduced risk in production bundles. Technologies and skills demonstrated span JavaScript/Node tooling, module graph analysis, integration testing, Babel tooling, and private package references.
June 2025
Activity
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Quality Metrics
Correctness91.0%
Maintainability88.8%
Architecture84.6%
Performance81.0%
AI Usage20.6%
Skills & Technologies
Programming Languages
JSONJSON5JavaScriptRustShellTypeScript
Technical Skills
AST ParsingAsynchronous ProgrammingBackend DevelopmentBuild SystemsBuild ToolsBundler DevelopmentBundlingCI/CDCI/CD ConfigurationCSS TransformersCachingCargoCode AnalysisCode CleanupCode Isolation
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