github/codeql
Jan 2025 – Oct 2025
10 Months active
Languages Used
C++QLqlC#JavaJavaScriptRubyRust
Technical Skills
C++ DevelopmentCode AnalysisCode DocumentationCode RefactoringCodeQLData Flow Analysis
Anders Schack-Mulligen
PROFILE
Anders Schack-mulligen
Over ten months, Andreas Schackmull engineered foundational improvements to static analysis in the github/codeql repository, focusing on control-flow, SSA, and taint analysis across Java, C#, and C++. He unified and refactored core libraries, modernized APIs, and standardized data-flow and guard logic to reduce duplication and improve cross-language consistency. His work included performance tuning, dead code elimination, and expanded test coverage, resulting in more accurate and maintainable analysis pipelines. By integrating caching, refining nullness and guard reasoning, and enhancing documentation, Andreas delivered robust, scalable infrastructure that accelerated onboarding, reduced false positives, and improved the reliability of security and correctness checks.
Overall Statistics
Feature vs Bugs
72%Features
Repository Contributions
298Total
Bugs
34
Commits
298
Features
86
Lines of code
40,301
Activity Months10
Your Network
716 people
Work History
October 2025
9 Commits • 3 Features
Oct 1, 2025Month: 2025-10 — Summary: Focused delivery across SSA infrastructure stabilization, enhanced security analysis for array taint tracking, and performance improvements in static analysis predicates, complemented by a targeted bug fix to reduce false positives in constant-expression detection. Key outcomes include a cleaner, shared SSA implementation, extended taint analysis coverage for Java arrays with tests and documentation, and measurable performance gains in predicate evaluation. These changes improve accuracy, maintainability, and readiness for future security-oriented features.
9 Commits • 3 Features
Oct 1, 2025Month: 2025-10 — Summary: Focused delivery across SSA infrastructure stabilization, enhanced security analysis for array taint tracking, and performance improvements in static analysis predicates, complemented by a targeted bug fix to reduce false positives in constant-expression detection. Key outcomes include a cleaner, shared SSA implementation, extended taint analysis coverage for Java arrays with tests and documentation, and measurable performance gains in predicate evaluation. These changes improve accuracy, maintainability, and readiness for future security-oriented features.
October 2025
September 2025
24 Commits • 10 Features
Sep 1, 2025September 2025 CodeQL monthly summary focused on strengthening the CFG/BasicBlock foundation, consolidating analysis libraries, and improving test harnesses across Java, Shared, and C#. The month delivered precise CFG labeling, library cleanups to reduce duplication, enhanced test acceptance workflows, and targeted performance fixes, delivering measurable business value through more accurate static analysis, maintainability, and faster feedback loops for developers and security teams. Key outcomes include improved CFG structure and labeling (replace BasicBlock entry predicate with a subclass; refine SuccessorType precision), Java Guards/QLL/Assertions cleanup with consolidated libraries, enhanced test harness with acceptance of test results and outputs, and the addition of change notes; fixes to Shared/Cfg to restore CFG accuracy; and Java performance fixes addressing regressions. Cross-language quality improvements were complemented by documentation enhancements and minor quality/nullness cleanups in support of a more reliable developer experience.
September 2025
24 Commits • 10 Features
Sep 1, 2025September 2025 CodeQL monthly summary focused on strengthening the CFG/BasicBlock foundation, consolidating analysis libraries, and improving test harnesses across Java, Shared, and C#. The month delivered precise CFG labeling, library cleanups to reduce duplication, enhanced test acceptance workflows, and targeted performance fixes, delivering measurable business value through more accurate static analysis, maintainability, and faster feedback loops for developers and security teams. Key outcomes include improved CFG structure and labeling (replace BasicBlock entry predicate with a subclass; refine SuccessorType precision), Java Guards/QLL/Assertions cleanup with consolidated libraries, enhanced test harness with acceptance of test results and outputs, and the addition of change notes; fixes to Shared/Cfg to restore CFG accuracy; and Java performance fixes addressing regressions. Cross-language quality improvements were complemented by documentation enhancements and minor quality/nullness cleanups in support of a more reliable developer experience.
August 2025
37 Commits • 11 Features
Aug 1, 2025August 2025 CodeQL monthly summary across the github/codeql repository. Delivered a set of high-impact improvements to static analysis, with a strong emphasis on precision, reliability, and cross-language consistency. Highlights include major enhancements to the Nullness analysis, core CFG/SSA improvements, and cross-language standardization, plus targeted testing and reliability work that improved developer feedback loops and reduced false positives/negatives.
37 Commits • 11 Features
Aug 1, 2025August 2025 CodeQL monthly summary across the github/codeql repository. Delivered a set of high-impact improvements to static analysis, with a strong emphasis on precision, reliability, and cross-language consistency. Highlights include major enhancements to the Nullness analysis, core CFG/SSA improvements, and cross-language standardization, plus targeted testing and reliability work that improved developer feedback loops and reduced false positives/negatives.
August 2025
July 2025
30 Commits • 8 Features
Jul 1, 2025Month: 2025-07 – Github CodeQL Repository (github/codeql) Key features delivered: - Tests: Updated and accepted Java and Kotlin test suites to align with new test changes, improving CI reliability and faster feedback. - Join-order and analysis enhancements: Improved join order and path analysis for better performance and correctness, including 2-column join on delta and better annotations that yielded noticeable performance gains. - Guards module refactor and enhancements: Refactored and cleaned up Guards module, simplified instantiation, renamed modules, and generalized wrapper guards for broader applicability. - Core data-flow and barrier guards: SSA barrier guard interface updated to use GuardValue; added validation wrappers and enhancements to BarrierGuards, including wrappers that may throw exceptions and improved usage patterns; leading to more robust data-flow controls. - Java performance and code quality improvements: Accept qltest changes, untangle code to improve join order, enhance ObjFlow performance, and remove ambiguous CCR formatting instructions; introduced Java/Guards change notes for traceability. - Documentation: Change note documenting the batch of Java/Guards and performance improvements. Major bugs fixed: - PathQL/PathGraph fixes: Restrict results to source literals; prune PathGraph for CSRF-unprotected paths; adjust Paths.qll to improve correctness and reduce noise. - Bug: Fix accidental CP in CFG for asserts: Corrected an accidental copy-paste in CFG related to asserts that impacted control flow analysis. Overall impact and accomplishments: - Substantial performance and correctness gains across CodeQL analysis, including faster join-order resolution, more accurate path analysis, and safer data-flow handling. These changes improve analyzer reliability, scalability, and developer productivity with clearer guard semantics and validated workflows. The updates also enhance test coverage and maintainability, enabling safer extensions in future batches. Technologies/skills demonstrated: - Java and Kotlin code and tests, CodeQL Java analysis, PathQL/PathGraph, data-flow analysis (SSA, BarrierGuards), test automation (qltest), Guards framework, ObjFlow, code refactoring and maintainability practices, and thorough documentation."
July 2025
30 Commits • 8 Features
Jul 1, 2025Month: 2025-07 – Github CodeQL Repository (github/codeql) Key features delivered: - Tests: Updated and accepted Java and Kotlin test suites to align with new test changes, improving CI reliability and faster feedback. - Join-order and analysis enhancements: Improved join order and path analysis for better performance and correctness, including 2-column join on delta and better annotations that yielded noticeable performance gains. - Guards module refactor and enhancements: Refactored and cleaned up Guards module, simplified instantiation, renamed modules, and generalized wrapper guards for broader applicability. - Core data-flow and barrier guards: SSA barrier guard interface updated to use GuardValue; added validation wrappers and enhancements to BarrierGuards, including wrappers that may throw exceptions and improved usage patterns; leading to more robust data-flow controls. - Java performance and code quality improvements: Accept qltest changes, untangle code to improve join order, enhance ObjFlow performance, and remove ambiguous CCR formatting instructions; introduced Java/Guards change notes for traceability. - Documentation: Change note documenting the batch of Java/Guards and performance improvements. Major bugs fixed: - PathQL/PathGraph fixes: Restrict results to source literals; prune PathGraph for CSRF-unprotected paths; adjust Paths.qll to improve correctness and reduce noise. - Bug: Fix accidental CP in CFG for asserts: Corrected an accidental copy-paste in CFG related to asserts that impacted control flow analysis. Overall impact and accomplishments: - Substantial performance and correctness gains across CodeQL analysis, including faster join-order resolution, more accurate path analysis, and safer data-flow handling. These changes improve analyzer reliability, scalability, and developer productivity with clearer guard semantics and validated workflows. The updates also enhance test coverage and maintainability, enabling safer extensions in future batches. Technologies/skills demonstrated: - Java and Kotlin code and tests, CodeQL Java analysis, PathQL/PathGraph, data-flow analysis (SSA, BarrierGuards), test automation (qltest), Guards framework, ObjFlow, code refactoring and maintainability practices, and thorough documentation."
June 2025
14 Commits • 4 Features
Jun 1, 2025June 2025: Delivered significant improvements to Java analysis in CodeQL, with a focus on CFG accuracy, guard reasoning, and test reliability. Implemented core Java CFG enhancements for asserts and AssertionError, improved guard/nullness analysis with caching to reduce false positives, and achieved performance gains around Struts detection. Completed comprehensive test cleanup to align results with analyzer behavior and removed false-positive markers. These changes collectively improve precision, stability, and performance of Java security and correctness checks, delivering measurable business value for static analysis users.
14 Commits • 4 Features
Jun 1, 2025June 2025: Delivered significant improvements to Java analysis in CodeQL, with a focus on CFG accuracy, guard reasoning, and test reliability. Implemented core Java CFG enhancements for asserts and AssertionError, improved guard/nullness analysis with caching to reduce false positives, and achieved performance gains around Struts detection. Completed comprehensive test cleanup to align results with analyzer behavior and removed false-positive markers. These changes collectively improve precision, stability, and performance of Java security and correctness checks, delivering measurable business value for static analysis users.
June 2025
May 2025
28 Commits • 9 Features
May 1, 2025May 2025 focused on delivering a unified Guards ecosystem across the CodeQL repo, consolidating core guard functionality into a Shared Guards Library Core and enabling cross-language adoption with Java and Shared BasicBlock integration. The month encompassed key architecture improvements (guards library, SSA/type enhancements), Java integration and refactors, performance tuning, and documentation updates. These changes deliver business value by reducing duplication, increasing analysis accuracy, and speeding developer onboarding and iteration.
May 2025
28 Commits • 9 Features
May 1, 2025May 2025 focused on delivering a unified Guards ecosystem across the CodeQL repo, consolidating core guard functionality into a Shared Guards Library Core and enabling cross-language adoption with Java and Shared BasicBlock integration. The month encompassed key architecture improvements (guards library, SSA/type enhancements), Java integration and refactors, performance tuning, and documentation updates. These changes deliver business value by reducing duplication, increasing analysis accuracy, and speeding developer onboarding and iteration.
April 2025
6 Commits • 3 Features
Apr 1, 2025April 2025 monthly highlights for github/codeql: Delivered cross-language static analysis enhancements focused on accuracy, reliability, and maintainability. C# PreSSA static analysis improvements refine control-flow identification using updated use-use predicates, reducing false positives in critical code paths. Swift SSA data-flow analysis improvements updated to use new use-use predicates, with refactoring of definitions/reads tracking (Ssa.qll and DataFlowPrivate.qll) to boost accuracy and efficiency; includes test updates and consistency checks. Also published SSA documentation and deprecation notes clarifying internal concepts (DefinitionExt, PhiReadNode) and preserving their functionality within DataFlowIntegration. These changes were supported by targeted tests, consistent test outputs, and comprehensive documentation. Business impact includes improved analysis accuracy, faster throughput, reduced maintenance risk, and clearer architectural guidance for SSA components.
6 Commits • 3 Features
Apr 1, 2025April 2025 monthly highlights for github/codeql: Delivered cross-language static analysis enhancements focused on accuracy, reliability, and maintainability. C# PreSSA static analysis improvements refine control-flow identification using updated use-use predicates, reducing false positives in critical code paths. Swift SSA data-flow analysis improvements updated to use new use-use predicates, with refactoring of definitions/reads tracking (Ssa.qll and DataFlowPrivate.qll) to boost accuracy and efficiency; includes test updates and consistency checks. Also published SSA documentation and deprecation notes clarifying internal concepts (DefinitionExt, PhiReadNode) and preserving their functionality within DataFlowIntegration. These changes were supported by targeted tests, consistent test outputs, and comprehensive documentation. Business impact includes improved analysis accuracy, faster throughput, reduced maintenance risk, and clearer architectural guidance for SSA components.
April 2025
March 2025
53 Commits • 17 Features
Mar 1, 2025Month: 2025-03 – github/codeql Overview: This month focused on strengthening SSA-based data-flow analysis across languages, refactoring core types, and improving build/test efficiency. Key features include Guards interface replacement, API modernization around SSA definitions, and maintenance gains through dead-code elimination and stage merging. Across C++, Java, Ruby, Rust, and other languages, a broad set of cross-language improvements were delivered to improve correctness, consistency, and scalability of the CodeQL data-flow engine. Key achievements delivered this month include a number of high-impact refactors and optimization efforts that collectively reduce maintenance burden, improve correctness, and accelerate analysis: - SSA: Replace the Guards interface in the SSA data-flow integration to use the updated contract (commit: c6761db2fc24080c92ee6cbce011b0c7f1858f0c). - C++: Replace DefinitionExt usage with Definition across the codebase, simplifying the API and reducing surface area (commit: 6ba1d2ef14d3b3345eb98747bbcdfdcd8998737d). - C++: Merge two cached stages to streamline processing and reduce runtime overhead (commit: 35687ea6981f5e5c71a8631f7b8235cd2a848268). - Ruby: Push in casts to Definition to delete the then-unused DefinitionExt, consolidating type handling (commit: 5e722eecf7853be6db8457801f69c9373695cd13). - SSA data-flow pruning and optimization: Implement a broad set of SSA data-flow improvements including skipping SSA definition nodes, skipping irrelevant phi input nodes, skipping phi nodes with unique successor, skipping identity steps, and a revised join-order; see commits 7c82f51381567f0d05c6bf97862fd2e57edb6021, c778bf63438c600d309c68b1acb3d09424756f98, 669f9261f17020003ad380130a5ff960aec0cd9a, 4e2ad9712ca53a4dba2158aa387874f1cc5650bc, 36532bc58c8400093579d87ea19e3f992a9ad696, 0162b84d206452a4909845d1d3a613cdd9bfe730. - SSA Def/HasSource API modernization across languages: Introduce ssaDefHasSource, WriteDefSourceNode, and related cross-language SSA data-flow integration work; see commits 1ded4df3fd6d78060a7b22428329c1f6ee69fb59, 4c420c5bae8cf1b2d3ba392a3c08f4d75ba34f0f, 8aedd63b9ef6c4ffda6fffe6b54278eb4ea212a4, d8e14a6b5545aacad2c387468591f20568dc4711, 6e9ebca977d3a0aec52af14830271c0bb4a1ad96, 308d15401fb73453b2463e00f6edc19273915a19, 25297cb2b6650ce55f4f2d0b52c454ea8760f14c, ca6444ce98faae024d48b36915a4661449ff10f6. - Java/SSA: Add support for skipping WriteDefinitions in use-use and related caching improvements (commit: 5aa7029934ce41e15eee9bcb3a1bc398ebf44f31). - Java: Fix TC magic in SystemProperty and other test-aligned changes (commit: dc0ca1ac18a5f71ee6dd6ed937f86c2167cf8f8e). - Misc: Stage overlap script added to streamline build/test workflow (commit: 8a67e4fddcb9e4ad5ae5aa93be573d1fd6a38785). - Cross-language test suite updates: Accept test changes across C#, Java, Ruby, Rust (commits b3bea973205486969a7d4ead931f5c7a90b97749, f27e8199a1ae35075eb8c03fdd871b559536cab8, e7e5f75949dc954c3bef045771d433cc2beecf96, ae47339d1a9853f6d82f90b5762a0c436d7d072b). - SSA: Deprecate the public DefinitionExt API to simplify usage (commit: 34554fd000176461e7c995896eb5ed10a933ff1f).
March 2025
53 Commits • 17 Features
Mar 1, 2025Month: 2025-03 – github/codeql Overview: This month focused on strengthening SSA-based data-flow analysis across languages, refactoring core types, and improving build/test efficiency. Key features include Guards interface replacement, API modernization around SSA definitions, and maintenance gains through dead-code elimination and stage merging. Across C++, Java, Ruby, Rust, and other languages, a broad set of cross-language improvements were delivered to improve correctness, consistency, and scalability of the CodeQL data-flow engine. Key achievements delivered this month include a number of high-impact refactors and optimization efforts that collectively reduce maintenance burden, improve correctness, and accelerate analysis: - SSA: Replace the Guards interface in the SSA data-flow integration to use the updated contract (commit: c6761db2fc24080c92ee6cbce011b0c7f1858f0c). - C++: Replace DefinitionExt usage with Definition across the codebase, simplifying the API and reducing surface area (commit: 6ba1d2ef14d3b3345eb98747bbcdfdcd8998737d). - C++: Merge two cached stages to streamline processing and reduce runtime overhead (commit: 35687ea6981f5e5c71a8631f7b8235cd2a848268). - Ruby: Push in casts to Definition to delete the then-unused DefinitionExt, consolidating type handling (commit: 5e722eecf7853be6db8457801f69c9373695cd13). - SSA data-flow pruning and optimization: Implement a broad set of SSA data-flow improvements including skipping SSA definition nodes, skipping irrelevant phi input nodes, skipping phi nodes with unique successor, skipping identity steps, and a revised join-order; see commits 7c82f51381567f0d05c6bf97862fd2e57edb6021, c778bf63438c600d309c68b1acb3d09424756f98, 669f9261f17020003ad380130a5ff960aec0cd9a, 4e2ad9712ca53a4dba2158aa387874f1cc5650bc, 36532bc58c8400093579d87ea19e3f992a9ad696, 0162b84d206452a4909845d1d3a613cdd9bfe730. - SSA Def/HasSource API modernization across languages: Introduce ssaDefHasSource, WriteDefSourceNode, and related cross-language SSA data-flow integration work; see commits 1ded4df3fd6d78060a7b22428329c1f6ee69fb59, 4c420c5bae8cf1b2d3ba392a3c08f4d75ba34f0f, 8aedd63b9ef6c4ffda6fffe6b54278eb4ea212a4, d8e14a6b5545aacad2c387468591f20568dc4711, 6e9ebca977d3a0aec52af14830271c0bb4a1ad96, 308d15401fb73453b2463e00f6edc19273915a19, 25297cb2b6650ce55f4f2d0b52c454ea8760f14c, ca6444ce98faae024d48b36915a4661449ff10f6. - Java/SSA: Add support for skipping WriteDefinitions in use-use and related caching improvements (commit: 5aa7029934ce41e15eee9bcb3a1bc398ebf44f31). - Java: Fix TC magic in SystemProperty and other test-aligned changes (commit: dc0ca1ac18a5f71ee6dd6ed937f86c2167cf8f8e). - Misc: Stage overlap script added to streamline build/test workflow (commit: 8a67e4fddcb9e4ad5ae5aa93be573d1fd6a38785). - Cross-language test suite updates: Accept test changes across C#, Java, Ruby, Rust (commits b3bea973205486969a7d4ead931f5c7a90b97749, f27e8199a1ae35075eb8c03fdd871b559536cab8, e7e5f75949dc954c3bef045771d433cc2beecf96, ae47339d1a9853f6d82f90b5762a0c436d7d072b). - SSA: Deprecate the public DefinitionExt API to simplify usage (commit: 34554fd000176461e7c995896eb5ed10a933ff1f).
February 2025
81 Commits • 19 Features
Feb 1, 2025February 2025 focused on stabilizing and modernizing CodeQL's SSA and data-flow pipelines across Java, C#, Ruby, Rust, and JS, delivering architecture improvements, broader test coverage, and performance refinements that reduce maintenance costs and increase analysis reliability. Key features delivered include: (1) SSA Def-Reaches module refactor and phi-read discipline—moved predicates to a new Reaches module, ignored phi-reads, restricted phi-read creation to reachable reads, and refactored ranking into a parameterized module for cleaner maintenance and more predictable analysis; (2) Cross-language predicate overhaul and use-use integration—implemented the new use-use predicates and aligned data-flow integration across C#, Ruby, and Rust to the updated predicates; (3) Deprecations and cleanup—dead code deprecation across C#/Ruby/Rust, deprecation of dependencies of deprecated predicates in Ruby, replacement of cached with nomagic for deprecated predicates, and remove getDefinitionExt references across languages; (4) Shared SSA library adoption and test modernization—Java BaseSSA switched to a shared SSA library, data-flow tests extended, and per-language test modules introduced (C#, Ruby, Rust) with qltest updates; (5) Performance improvements and code cleanup—minor performance tweaks to reduce tuple duplication, removal of unused predicates and components, and cross-language bug fixes to simplify maintenance. Major bugs fixed in February include: Dataflow join-order issue resolved; SSA input node guard logic corrected; cross-language fixes for adjacentReadPairSameVar in C#/Ruby/Rust; tests updated to reflect skip of useless input nodes; and guard logic corrections for SSA input nodes. These fixes improve query accuracy, reliability, and testing efficiency. Overall impact and business value: stronger, more maintainable SSA/data-flow infrastructure reduces risk of incorrect query results, accelerates test cycles, and enables faster onboarding for new languages and predicates, while preserving correctness across multi-language data-flow integrations. Technologies/skills demonstrated: multi-language SSA architecture, refactoring at module boundaries, predicate engineering, test modularization, cross-language data-flow integration, API cleanup, and performance optimization across Java, C#, Ruby, Rust, and JS.
81 Commits • 19 Features
Feb 1, 2025February 2025 focused on stabilizing and modernizing CodeQL's SSA and data-flow pipelines across Java, C#, Ruby, Rust, and JS, delivering architecture improvements, broader test coverage, and performance refinements that reduce maintenance costs and increase analysis reliability. Key features delivered include: (1) SSA Def-Reaches module refactor and phi-read discipline—moved predicates to a new Reaches module, ignored phi-reads, restricted phi-read creation to reachable reads, and refactored ranking into a parameterized module for cleaner maintenance and more predictable analysis; (2) Cross-language predicate overhaul and use-use integration—implemented the new use-use predicates and aligned data-flow integration across C#, Ruby, and Rust to the updated predicates; (3) Deprecations and cleanup—dead code deprecation across C#/Ruby/Rust, deprecation of dependencies of deprecated predicates in Ruby, replacement of cached with nomagic for deprecated predicates, and remove getDefinitionExt references across languages; (4) Shared SSA library adoption and test modernization—Java BaseSSA switched to a shared SSA library, data-flow tests extended, and per-language test modules introduced (C#, Ruby, Rust) with qltest updates; (5) Performance improvements and code cleanup—minor performance tweaks to reduce tuple duplication, removal of unused predicates and components, and cross-language bug fixes to simplify maintenance. Major bugs fixed in February include: Dataflow join-order issue resolved; SSA input node guard logic corrected; cross-language fixes for adjacentReadPairSameVar in C#/Ruby/Rust; tests updated to reflect skip of useless input nodes; and guard logic corrections for SSA input nodes. These fixes improve query accuracy, reliability, and testing efficiency. Overall impact and business value: stronger, more maintainable SSA/data-flow infrastructure reduces risk of incorrect query results, accelerates test cycles, and enables faster onboarding for new languages and predicates, while preserving correctness across multi-language data-flow integrations. Technologies/skills demonstrated: multi-language SSA architecture, refactoring at module boundaries, predicate engineering, test modularization, cross-language data-flow integration, API cleanup, and performance optimization across Java, C#, Ruby, Rust, and JS.
February 2025
January 2025
16 Commits • 2 Features
Jan 1, 2025January 2025 focused on strengthening taint analysis and dataflow architecture to improve CodeQL's security scanning capabilities. Delivered two major features with cross-language impact, stabilized the dataflow pipeline, and set the stage for faster, more accurate analyses across languages.
January 2025
16 Commits • 2 Features
Jan 1, 2025January 2025 focused on strengthening taint analysis and dataflow architecture to improve CodeQL's security scanning capabilities. Delivered two major features with cross-language impact, stabilized the dataflow pipeline, and set the stage for faster, more accurate analyses across languages.
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Quality Metrics
Correctness89.0%
Maintainability89.2%
Architecture87.2%
Performance80.8%
AI Usage20.0%
Skills & Technologies
Programming Languages
C#C++JavaJavaScriptKotlinMarkdownPythonQLRubyRust
Technical Skills
API DesignBug FixingC# DevelopmentC# Language FeaturesC++ DevelopmentCI/CDCachingCode AnalysisCode CleanupCode DocumentationCode OptimizationCode QualityCode RefactoringCode Review Process ImprovementCodeQL
Repositories Contributed To
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