google/mozc
Oct 2024 – Oct 2025
13 Months active
Languages Used
C++GYPMarkdownYAMLJapaneseProtoPythontsv
Technical Skills
Build SystemBuild System ConfigurationC++C++ DevelopmentCI/CD ConfigurationCode Organization
Hiroyuki Komatsu
PROFILE
Hiroyuki Komatsu
Komatsu led core development on google/mozc, delivering robust input method features and infrastructure improvements. Over 13 months, Komatsu engineered API refactors, cross-platform build automation, and dictionary enhancements, focusing on stability and maintainability. Using C++, Python, and Bazel, Komatsu modernized the codebase by introducing immutable data structures, optimizing build systems, and expanding emoji and linguistic data support. The work included rigorous regression testing, packaging automation, and accessibility improvements, ensuring reliable releases across macOS and Windows. By streamlining dependency management and refining code quality, Komatsu enabled faster iteration and safer deployments, demonstrating deep technical expertise in large-scale software engineering and release management.
Overall Statistics
Feature vs Bugs
67%Features
Repository Contributions
382Total
Bugs
66
Commits
382
Features
133
Lines of code
59,463
Activity Months13
Your Network
4172 people
Work History
October 2025
9 Commits • 4 Features
Oct 1, 2025October 2025 focused on stabilizing the Mozc release pipeline, expanding platform compatibility, and strengthening test coverage. Key improvements delivered across google/mozc include packaging reliability, flexible versioning, and enhanced typing quality tests, with attention to business value and cross-platform readiness.
9 Commits • 4 Features
Oct 1, 2025October 2025 focused on stabilizing the Mozc release pipeline, expanding platform compatibility, and strengthening test coverage. Key improvements delivered across google/mozc include packaging reliability, flexible versioning, and enhanced typing quality tests, with attention to business value and cross-platform readiness.
October 2025
September 2025
42 Commits • 13 Features
Sep 1, 2025September 2025: Focused on stability, build reliability, and data accuracy for google/mozc. Delivered dependency upgrades, API cleanup, enhanced tests, packaging and distribution improvements, and automation utilities that streamline versioning and data updates. The work reduces maintenance risk, accelerates releases, and improves cross-platform distribution.
September 2025
42 Commits • 13 Features
Sep 1, 2025September 2025: Focused on stability, build reliability, and data accuracy for google/mozc. Delivered dependency upgrades, API cleanup, enhanced tests, packaging and distribution improvements, and automation utilities that streamline versioning and data updates. The work reduces maintenance risk, accelerates releases, and improves cross-platform distribution.
August 2025
33 Commits • 8 Features
Aug 1, 2025August 2025 — Google Mozc: Key features delivered, major fixes, and measurable impact for reliability and maintainability. Delivered user-facing tooling and regression tests, cleaned API surfaces, and improved release hygiene, reflecting strong business value through faster debugging, safer mappings, and clearer APIs.
33 Commits • 8 Features
Aug 1, 2025August 2025 — Google Mozc: Key features delivered, major fixes, and measurable impact for reliability and maintainability. Delivered user-facing tooling and regression tests, cleaned API surfaces, and improved release hygiene, reflecting strong business value through faster debugging, safer mappings, and clearer APIs.
August 2025
July 2025
43 Commits • 26 Features
Jul 1, 2025July 2025 monthly summary for google/mozc focusing on stability, packaging, and developer experience improvements. Delivered hardening validations, automated recovery workflows, and packaging/configuration enhancements that reduce release risk and improve user experience.
July 2025
43 Commits • 26 Features
Jul 1, 2025July 2025 monthly summary for google/mozc focusing on stability, packaging, and developer experience improvements. Delivered hardening validations, automated recovery workflows, and packaging/configuration enhancements that reduce release risk and improve user experience.
June 2025
30 Commits • 11 Features
Jun 1, 2025June 2025 monthly summary for google/mozc focused on architecture modernization, dependency modernization, and build health improvements that enable faster iteration and more robust cross-platform behavior.
30 Commits • 11 Features
Jun 1, 2025June 2025 monthly summary for google/mozc focused on architecture modernization, dependency modernization, and build health improvements that enable faster iteration and more robust cross-platform behavior.
June 2025
May 2025
24 Commits • 8 Features
May 1, 2025May 2025 monthly summary for google/mozc: Focused on improving typing correctness, reliability, and code quality. Delivered new IsNumber exception rules to broaden numeric input support, hardened preedit flow when empty, and significant testing infrastructure enhancements. Fixed multiple bug paths affecting error reporting, transliteration behavior, and build/test reliability, while modernizing code using explicit headers, std::unique_ptr, Utf8Format, and updated dependencies. These efforts enhance user experience, reduce release risk, and lay groundwork for faster iteration.
May 2025
24 Commits • 8 Features
May 1, 2025May 2025 monthly summary for google/mozc: Focused on improving typing correctness, reliability, and code quality. Delivered new IsNumber exception rules to broaden numeric input support, hardened preedit flow when empty, and significant testing infrastructure enhancements. Fixed multiple bug paths affecting error reporting, transliteration behavior, and build/test reliability, while modernizing code using explicit headers, std::unique_ptr, Utf8Format, and updated dependencies. These efforts enhance user experience, reduce release risk, and lay groundwork for faster iteration.
April 2025
10 Commits • 3 Features
Apr 1, 2025April 2025 Mozc monthly summary:4 key areas shaped the quarter’s outcomes. Features delivered: (1) Japanese Romaji-to-Kana conversion enhancement adding a rule to map "tch" to the kana sequence っ + ch with test coverage to verify the conversion, (2) Mozc dictionary expansion introducing a large set of words and place names to improve input accuracy and coverage, and (3) Testing and validation enhancements introducing evaluation and regression tests focused on number conversion to boost robustness (e.g., "にじ" → "虹" and "ごかい" → "誤解"). Major bugs fixed: (1) Build environment compatibility and cleanup to stabilize builds across platforms by addressing Abseil compatibility, updating SDK/Xcode references, removing deprecated files/references, and adding compatibility headers. Overall impact and accomplishments: improving input quality and coverage, ensuring reliable, cross‑platform builds, and strengthening validation to reduce regressions, thereby delivering measurable business value from developers’ and users’ perspectives. Technologies/skills demonstrated: C++ rule implementation, test-driven development, dictionary management, Abseil tooling and compatibility work, Xcode/macOS SDK updates, and cross-platform build stabilization.
10 Commits • 3 Features
Apr 1, 2025April 2025 Mozc monthly summary:4 key areas shaped the quarter’s outcomes. Features delivered: (1) Japanese Romaji-to-Kana conversion enhancement adding a rule to map "tch" to the kana sequence っ + ch with test coverage to verify the conversion, (2) Mozc dictionary expansion introducing a large set of words and place names to improve input accuracy and coverage, and (3) Testing and validation enhancements introducing evaluation and regression tests focused on number conversion to boost robustness (e.g., "にじ" → "虹" and "ごかい" → "誤解"). Major bugs fixed: (1) Build environment compatibility and cleanup to stabilize builds across platforms by addressing Abseil compatibility, updating SDK/Xcode references, removing deprecated files/references, and adding compatibility headers. Overall impact and accomplishments: improving input quality and coverage, ensuring reliable, cross‑platform builds, and strengthening validation to reduce regressions, thereby delivering measurable business value from developers’ and users’ perspectives. Technologies/skills demonstrated: C++ rule implementation, test-driven development, dictionary management, Abseil tooling and compatibility work, Xcode/macOS SDK updates, and cross-platform build stabilization.
April 2025
March 2025
26 Commits • 11 Features
Mar 1, 2025March 2025 Mozc monthly summary focusing on cross-platform build stability, data quality improvements, and packaging accessibility. The team delivered Windows build fixes, macOS Xcode build flags compatibility, zip-code data workflow refresh, dictionary enhancements based on user feedback, and packaging visibility, alongside targeted code maintenance to improve long-term maintainability.
March 2025
26 Commits • 11 Features
Mar 1, 2025March 2025 Mozc monthly summary focusing on cross-platform build stability, data quality improvements, and packaging accessibility. The team delivered Windows build fixes, macOS Xcode build flags compatibility, zip-code data workflow refresh, dictionary enhancements based on user feedback, and packaging visibility, alongside targeted code maintenance to improve long-term maintainability.
February 2025
31 Commits • 6 Features
Feb 1, 2025February 2025 monthly summary for google/mozc focused on stabilizing the rewriter pipeline, API hygiene, and cross‑platform reliability. Delivered architectural refactors, build modernization, and targeted fixes that reduce maintenance burden and improve business value. Key features delivered: - VariantsRewriter FormTypes API refactor: Move GetFormTypesFromStringPair to VariantsRewriter with adjusted arguments/return type and updated usage to Util::FormType. - VariantsRewriter cleanup and build modernization: code cleanup, build/config changes, added candidate.cc to the build, pass DataManager by const reference, and modernized Candidate to a class. - Candidate logic refactor and CorrectionRewriter updates: improved candidate management, added logic to create alternative candidates, and relocated Segments::Candidate to Candidate in header; updates to CorrectionRewriter. - Rewriter constructors const‑correctness improvements: adopt const references in constructor parameters where appropriate. - Variants API extension: added variants::GetDescription() and variants::GetPrefix() to expose metadata. Major bugs fixed: - Windows build fixes and general build error resolutions to restore CI stability. - Dependency compatibility updates and rollbacks for Abseil, Protobuf, and Googletest to align versions and build configurations. Overall impact and accomplishments: - Improved API stability and maintainability of the rewriter pipeline, enabling easier future refactors and feature work. - Increased cross‑platform reliability (notably Windows) and more predictable builds, reducing emergency fixes and rework. - Clearer separation of concerns in candidate management and rewriter components, accelerating future enhancements. Technologies/skills demonstrated: - C++ modernization and refactoring patterns (const-correctness, class redesign, header encapsulation). - Build systems and configuration management (gyp, MODULE.bazel) and third‑party dependency handling. - Code quality practices (typos fixes, naming clarity, and architectural refactors).
31 Commits • 6 Features
Feb 1, 2025February 2025 monthly summary for google/mozc focused on stabilizing the rewriter pipeline, API hygiene, and cross‑platform reliability. Delivered architectural refactors, build modernization, and targeted fixes that reduce maintenance burden and improve business value. Key features delivered: - VariantsRewriter FormTypes API refactor: Move GetFormTypesFromStringPair to VariantsRewriter with adjusted arguments/return type and updated usage to Util::FormType. - VariantsRewriter cleanup and build modernization: code cleanup, build/config changes, added candidate.cc to the build, pass DataManager by const reference, and modernized Candidate to a class. - Candidate logic refactor and CorrectionRewriter updates: improved candidate management, added logic to create alternative candidates, and relocated Segments::Candidate to Candidate in header; updates to CorrectionRewriter. - Rewriter constructors const‑correctness improvements: adopt const references in constructor parameters where appropriate. - Variants API extension: added variants::GetDescription() and variants::GetPrefix() to expose metadata. Major bugs fixed: - Windows build fixes and general build error resolutions to restore CI stability. - Dependency compatibility updates and rollbacks for Abseil, Protobuf, and Googletest to align versions and build configurations. Overall impact and accomplishments: - Improved API stability and maintainability of the rewriter pipeline, enabling easier future refactors and feature work. - Increased cross‑platform reliability (notably Windows) and more predictable builds, reducing emergency fixes and rework. - Clearer separation of concerns in candidate management and rewriter components, accelerating future enhancements. Technologies/skills demonstrated: - C++ modernization and refactoring patterns (const-correctness, class redesign, header encapsulation). - Build systems and configuration management (gyp, MODULE.bazel) and third‑party dependency handling. - Code quality practices (typos fixes, naming clarity, and architectural refactors).
February 2025
January 2025
31 Commits • 16 Features
Jan 1, 2025January 2025 (Month: 2025-01) monthly summary for google/mozc. Focused on delivering cross-rewriter resizing support, stabilizing the build system, and improving code quality to increase reliability, maintainability, and developer velocity. Highlights include feature deliveries, targeted bug fixes, and infrastructure improvements that reduce build risk and enable modular feature toggling.
January 2025
31 Commits • 16 Features
Jan 1, 2025January 2025 (Month: 2025-01) monthly summary for google/mozc. Focused on delivering cross-rewriter resizing support, stabilizing the build system, and improving code quality to increase reliability, maintainability, and developer velocity. Highlights include feature deliveries, targeted bug fixes, and infrastructure improvements that reduce build risk and enable modular feature toggling.
December 2024
26 Commits • 9 Features
Dec 1, 2024December 2024 Mozc monthly summary for google/mozc. Key deliverables focus on core refactors, API cleanups, and stability improvements that reduce risk and improve runtime efficiency. Highlights include a comprehensive refactor of UserBoundaryHistoryRewriter with ApplyConversion and a split of ResizeOrInsert, modernization of data structures (value storage_ usage, std::array-based LengthArray) and transition from history_segments to conversion_segments; introduction of SegmentsKey and seg_size to improve key/length management. Additional feature work includes MergerRewriter::Rewrite simplification; Converter API cleanup removing segments_size with tests for Converter::ResizeSegment; and architectural enhancements introducing CheckResizeSegmentsRequest with validation enforced before Rewrite across RewriterInterface and CalculatorRewriter. Unification of ResizeSegment and ResizeSegments consolidates logic, reduces duplication, and improves maintainability. Cross-cutting maintenance includes updating Protobuf to v29.1, excluding lazy_repeated_field*.cc in protobuf.gyp, Windows build fixes, and mozc_win_build_target enhancements. These efforts enhance maintainability, test coverage, performance, and cross-platform stability, positioning Mozc for scalable growth in 2025.
26 Commits • 9 Features
Dec 1, 2024December 2024 Mozc monthly summary for google/mozc. Key deliverables focus on core refactors, API cleanups, and stability improvements that reduce risk and improve runtime efficiency. Highlights include a comprehensive refactor of UserBoundaryHistoryRewriter with ApplyConversion and a split of ResizeOrInsert, modernization of data structures (value storage_ usage, std::array-based LengthArray) and transition from history_segments to conversion_segments; introduction of SegmentsKey and seg_size to improve key/length management. Additional feature work includes MergerRewriter::Rewrite simplification; Converter API cleanup removing segments_size with tests for Converter::ResizeSegment; and architectural enhancements introducing CheckResizeSegmentsRequest with validation enforced before Rewrite across RewriterInterface and CalculatorRewriter. Unification of ResizeSegment and ResizeSegments consolidates logic, reduces duplication, and improves maintainability. Cross-cutting maintenance includes updating Protobuf to v29.1, excluding lazy_repeated_field*.cc in protobuf.gyp, Windows build fixes, and mozc_win_build_target enhancements. These efforts enhance maintainability, test coverage, performance, and cross-platform stability, positioning Mozc for scalable growth in 2025.
December 2024
November 2024
69 Commits • 17 Features
Nov 1, 2024November 2024 monthly performance summary for google/mozc: Delivered broader emoji support and data updates, advanced API and architecture improvements, and stabilizing platform readiness. Key outcomes include expanded Emoji 16.0 coverage with CLDR 46 data and data file updates; incorporation of user-reported dictionary entries and test cases for real-world robustness; major API redesign of ConversionRequest with ComposerData, builder pattern, and value semantics to reduce churn and improve reliability; performance and maintainability enhancements including absl::btree_set usage for prediction queries and core Converter refactor with HistoryReconstructor extraction and ReverseConverter isolation; and cross-platform build/stability work (Qt 6.8.0, lint fixes, and dependency updates). These efforts drive higher accuracy, lower latency, easier maintenance, and faster feature iteration across platforms.
November 2024
69 Commits • 17 Features
Nov 1, 2024November 2024 monthly performance summary for google/mozc: Delivered broader emoji support and data updates, advanced API and architecture improvements, and stabilizing platform readiness. Key outcomes include expanded Emoji 16.0 coverage with CLDR 46 data and data file updates; incorporation of user-reported dictionary entries and test cases for real-world robustness; major API redesign of ConversionRequest with ComposerData, builder pattern, and value semantics to reduce churn and improve reliability; performance and maintainability enhancements including absl::btree_set usage for prediction queries and core Converter refactor with HistoryReconstructor extraction and ReverseConverter isolation; and cross-platform build/stability work (Qt 6.8.0, lint fixes, and dependency updates). These efforts drive higher accuracy, lower latency, easier maintenance, and faster feature iteration across platforms.
October 2024
8 Commits • 1 Features
Oct 1, 2024October 2024 monthly summary for google/mozc focused on stability, correctness, and developer experience. Key work centered on making ConversionRequest handling immutable and per-call instantiations to prevent test flakiness, correcting protocol buffer include paths after a rename, and improving onboarding and build reliability through documentation and typo fixes. These changes reduce flaky tests, align with const-correctness goals, and streamline developer workflows across the repository.
8 Commits • 1 Features
Oct 1, 2024October 2024 monthly summary for google/mozc focused on stability, correctness, and developer experience. Key work centered on making ConversionRequest handling immutable and per-call instantiations to prevent test flakiness, correcting protocol buffer include paths after a rename, and improving onboarding and build reliability through documentation and typo fixes. These changes reduce flaky tests, align with const-correctness goals, and streamline developer workflows across the repository.
October 2024
Activity
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Quality Metrics
Correctness93.8%
Maintainability94.0%
Architecture91.8%
Performance87.6%
AI Usage20.0%
Skills & Technologies
Programming Languages
BazelBzlC++CSSDockerfileEmacs LispGYPGitHTMLJapanese
Technical Skills
API DesignAccessibilityAlgorithm DesignAlgorithm OptimizationBackend DevelopmentBazelBug FixingBuild AutomationBuild SystemBuild System ConfigurationBuild System ManagementBuild System OptimizationBuild SystemsBuild ToolsBuilder Pattern
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