qt6-migration-pipeline/MIGRATION_STATUS.md

Qt5/C++11 → Qt6/C++17 Migration Status

Last Updated: 2026-08-22 12:45
Session: 009-build-rti-dds-guard-fixes-comp
Branch: main → qt-migration-legatus submodule → feature/qt6-migration-basis-modules

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📊 Current Status

Build Validation Summary

Configuration	Status	Notes
BUILD_RTI=OFF	✅ SUCCESS (0 errors)	Completed in previous session
BUILD_RTI=ON	✅ DDS Core SUCCESS	libddsconnector.so built successfully
C++ Standard	C++17	Enforced due to RTI DDS 7.7.0 incompatibility with C++20+

Latest Commit

• Submodule: d7c8c9e6 → feature/qt6-migration-basis-modules
• Main Repo: 4340d47a → main
• Changes: BUILD_RTI=ON DDS header includes and logger initialization fixes

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✅ Completed Work

Session 009: BUILD_RTI=ON DDS Fixes

Fixed Files (6 files changed, 22 insertions, 20 deletions)

1. Lts/DDS/Generic/dynamic_data_reader.h

   • Added #include <rti/core/xtypes/DynamicDataImpl.hpp>
   • Resolved incomplete type error when deleting DynamicDataImpl* pointers
   • Added m_logger member variable declaration

2. Lts/DDS/DTS/generic_dts_impl.h

   • Added m_logger member variable declaration (LOGGER_T&)

3. Lts/DDS/DDSConnector/pub_sub_base.cpp

   • Fixed logger initialization pattern
   • Changed from non-existent NGL::getNGLLogger() to NGL::NGLLoggerBootstrap::getNGLRootLogger().getNGLLogger()

4. Lts/Common/LtsSession/lts_session_data_dds.h

   • Added DataPluginBase::Interface forward declaration to both #ifdef BUILD_RTI and #else blocks
   • Ensures consistent compilation across both build configurations

5. Lts/Common/LtsUtils/LtsUtilsCore/CMakeLists.txt

   • Fixed include path from /.. to /../.. for LtsUtilsCoreHeaderOnly target

6. tests/CMakeLists.txt

   • Moved Grantlee test filtering BEFORE executable creation
   • Prevents build failures when Grantlee is disabled

Build Results

✅ BUILD_RTI=OFF: 0 errors, 0 warnings (new)
✅ BUILD_RTI=ON: DDS core components compile successfully
   - libddsconnector.so created
   - ddsconnector library links successfully
⚠️  Remaining errors in unrelated modules (pre-existing):
   - IsmDataPluginInterface: linker error -lsvcIsmCommon
   - IsmShared: linker error -lsvcIsmCommon
   - BuildingControlBsm: svctabcommon_export.h not found

Session 008: BUILD_RTI=OFF Validation

• Fixed Qt6 API compatibility issues (~558 QJsonObject initializer list fixes)
• Fixed Header struct member access patterns
• Fixed BatteryState/BatteryAlarm toJson()/fromJson() methods
• Fixed UAVAction, UAVStatus, and other telegram methods
• Added missing #include <iomanip> to lts_coordinate.cpp
• Fixed Qt6 include paths throughout codebase
• Result: 0 errors, only pre-existing warnings remain

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🎯 Key Technical Decisions

C++17 Standard Enforcement

Decision: All build configurations enforce C++17 standard.

Rationale: RTI Connext DDS 7.7.0 has known header bugs with C++20/C++23 that cause compilation failures. While Qt 6.10.2 fully supports C++23, the RTI dependency is a hard blocker.

Component	C++14	C++17	C++20	C++23
RTI Connext DDS 7.7.0	✅	✅	❌	❌
Qt 6.10.2	✅	✅	✅	✅
Project Standard	-	✅	-	-

Impact: All CMakeLists.txt, presets, toolchains, and compiler flags unified to C++17.

RTI DDS Integration Pattern

Strategy: RTI Connext DDS is treated as an optional dependency with clean separation:

1. BUILD_RTI=OFF: All RTI code excluded via #ifdef BUILD_RTI guards
2. BUILD_RTI=ON: RTI headers included with stable guards/stubs
3. No vendor header patches: RTI headers used as-is, compatibility handled in wrapper code
4. Forward declarations: Minimize header dependencies for faster compilation

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📋 Migration Progress

Completed Modules

Module	Status	BUILD_RTI=OFF	BUILD_RTI=ON	Notes
Lts/Common	✅ Complete	✅	✅	All submodules compile
Lts/DDS/Core	✅ Complete	✅	✅	DDS core infrastructure
Lts/DDS/DTS	✅ Complete	✅	✅	Generic DTS implementation
Lts/DDS/Generic	✅ Complete	✅	✅	Dynamic data handling
Lts/DDS/DDSConnector	✅ Complete	✅	✅	Pub/sub base classes
Lts/DDS/Discovery	🟡 Partial	✅	⏳	Pending full validation
TetraIF	🟡 Partial	⏳	⏳	Migration in progress
Z-Modules	🟡 Partial	⏳	⏳	Some submodules complete

Remaining Modules

• Lts/Plugins (60 submodules)
• Lts/Projects (5 submodules)
• Lts/Proxies (13 submodules)
• Lts/Services (47 submodules)
• TetraIF (completion)
• Z-Modules (completion)

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🔧 Infrastructure

Git Configuration

Main Repo: git@devel:lifemaps/qt6-migration-pipeline.git (main)
Submodule: git@devel:lifemaps/qt-migration-legatus.git (feature/qt6-migration-basis-modules)
SSH Config: devel → gitea.life-maps.com:2223 (IdentityFile: ~/.ssh/twi-devel.gitea)

Docker Build Environment

Image: migration-pipeline:ubuntu26.04
Base: Ubuntu 26.04
Qt: 6.10.2
CMake: 3.16+
C++: 17 (enforced)
RTI: Connext DDS 7.7.0

Build Commands

# BUILD_RTI=OFF (default)
docker run --rm -v $(pwd):/repo migration-pipeline:ubuntu26.04 \
  cmake --build /repo/build --parallel

# BUILD_RTI=ON
docker run --rm -v $(pwd):/repo migration-pipeline:ubuntu26.04 \
  cmake --build /repo/build-rti --parallel

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⏭️ Next Steps

Immediate (Next 4 hours)

1. ⏳ Resolve non-DDS build issues

   • IsmDataPluginInterface: Fix -lsvcIsmCommon linker dependency
   • IsmShared: Fix -lsvcIsmCommon linker dependency
   • BuildingControlBsm: Fix svctabcommon_export.h include path

2. ⏳ Complete Lts/DDS module validation

   • Build and test remaining DDS submodules
   • Verify integration with Qt6 event loop

3. ⏳ Update MIGRATION_STATUS.md

   • Auto-commit every 4 hours or at milestones
   • Track build status and blockers

Short-term (This week)

4. ⏳ Resume Lts module migration

   • Lts/Plugins: Prioritize core functionality submodules
   • Lts/Proxies: Complete TrainingAreaBase and related modules
   • Lts/Services: Address InfrastructureManagement dependencies

5. ⏳ TetraIF completion

   • Finish Qt6 migration
   • Validate with existing tests

6. ⏳ Z-Modules completion

   • Identify remaining unmigrated submodules
   • Complete migration and validation

Medium-term (Next 2 weeks)

7. ⏳ Full build validation

   • Complete BUILD_RTI=ON with all modules
   • Integration testing with RTI DDS

8. ⏳ CI/CD pipeline

   • Validate GitHub Actions workflow
   • Ensure submodule checkout works correctly
   • Test artifact generation

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📝 Auto-Update Policy

This document is automatically updated:

• Every 4 hours during active migration work
• At each milestone (successful build, module completion, blocker resolution)
• On every commit to main branch or submodule

Automation: Manual updates committed with migration work until automation script is implemented.

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📞 Contact & References

• Repository: lifemaps/qt6-migration-pipeline
• Submodule: lifemaps/qt-migration-legatus
• Branch: feature/qt6-migration-basis-modules
• Session Log: Checkpoints 001-009 in .git/ directory
• Migration Scripts: ./migration/, ./final-migration/

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Generated: 2026-08-22 12:45
Session: 009-build-rti-dds-guard-fixes-comp
Status: BUILD_RTI=ON DDS Core ✅ | Non-DDS Issues ⏳