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https://issues.apache.org/jira/browse/THRIFT-6312?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18117277#comment-18117277
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Jens Geyer commented on THRIFT-6312:
------------------------------------
Withdrawn. {{WITH_MT}} being a no-op is not a bug to fix: it is load bearing by
accident.
{{dd8ecde06}} moved the project away from a statically linked Windows compiler,
and {{doc/ReleaseManagement.md}} has said since then that the released compiler
"requires Visual C++ Runtime due to ASF regulations". Repairing {{WITH_MT}}
would have turned the release build straight back into the statically linked
one that commit removed.
What is actually stale is the other half of that cleanup: the document still
asked the release manager to check for "only kernel32.dll", and
{{build/docker/msvc/build-compiler.bat}} still passed {{-DWITH_MT=ON}}. That is
THRIFT-6320, which replaces this issue.
_Drafted with AI assistance (Claude Opus 5); reviewed and posted by Jens Geyer._
> WITH_MT does not select the static runtime any more
> ---------------------------------------------------
>
> Key: THRIFT-6312
> URL: https://issues.apache.org/jira/browse/THRIFT-6312
> Project: Thrift
> Issue Type: Bug
> Components: Build Process
> Reporter: Jens Geyer
> Priority: Major
> Fix For: 0.26.0
>
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> h2. Symptom
> A compiler built with {{-DWITH_MT=ON}} - which is how
> {{build/docker/msvc/build-compiler.bat}} and the manual instructions in
> {{doc/ReleaseManagement.md}} build the Windows compiler that ships with a
> release - imports the shared C and C++ runtime:
> {noformat}
> KERNEL32.dll
> ole32.dll
> MSVCP140.dll
> VCRUNTIME140.dll
> VCRUNTIME140_1.dll
> api-ms-win-crt-heap-l1-1-0.dll
> api-ms-win-crt-runtime-l1-1-0.dll
> api-ms-win-crt-stdio-l1-1-0.dll
> api-ms-win-crt-time-l1-1-0.dll
> api-ms-win-crt-string-l1-1-0.dll
> api-ms-win-crt-filesystem-l1-1-0.dll
> api-ms-win-crt-locale-l1-1-0.dll
> api-ms-win-crt-math-l1-1-0.dll
> api-ms-win-crt-convert-l1-1-0.dll
> {noformat}
> {{doc/ReleaseManagement.md}} requires the released executable to depend on
> {{kernel32.dll}} only, so that it runs on a machine with no Visual C++
> redistributable installed. The whole point of {{WITH_MT}} is to produce that.
> Observed on a {{windows-2025}} GitHub runner, CMake 3.31.6 with Visual Studio
> 2022. The container that builds the release compiler installs CMake 4.1.2.
> h2. Cause
> {{build/cmake/DefinePlatformSpecifc.cmake}} implements {{WITH_MT}} by
> rewriting the compiler flag variables:
> {code}
> foreach(CompilerFlag ${CompilerFlags})
> string(REPLACE "/MD" "/MT" ${CompilerFlag} "${${CompilerFlag}}")
> endforeach()
> {code}
> Policy [CMP0091|https://cmake.org/cmake/help/latest/policy/CMP0091.html] took
> the MSVC runtime selection out of the per configuration compiler flag
> variables ({{CMAKE_CXX_FLAGS_RELEASE}} and its siblings, which is exactly the
> list the loop above walks) and moved it to the {{MSVC_RUNTIME_LIBRARY}}
> target property, which the {{CMAKE_MSVC_RUNTIME_LIBRARY}} variable
> initialises. That policy is NEW whenever a project requires CMake 3.15 or
> newer, and the top level {{CMakeLists.txt}} requires 3.16.
> So there is no {{/MD}} left in those variables, the replacement matches
> nothing, and {{WITH_MT}} does nothing at all. Neither {{CMP0091}} nor
> {{CMAKE_MSVC_RUNTIME_LIBRARY}} appears anywhere in the tree.
> It fails silently. The build succeeds, the configure summary still prints
> {{Using static runtime library: ON}}, and the libraries are still named
> {{thriftmt}} - the name promises a static runtime the binaries do not have.
> h2. Fix
> Set {{CMAKE_MSVC_RUNTIME_LIBRARY}} to
> {{MultiThreaded$<$<CONFIG:Debug>:Debug>}} when {{WITH_MT}} is on, before any
> target is created. The flag rewriting stays, because it is what still applies
> to a build that sets {{CMP0091}} to OLD.
> h2. Unrelated, but in the same list
> {{ole32.dll}} is expected and is not a redistributable: it is a Windows
> system DLL present on every Windows installation, pulled in by the
> {{CoCreateGuid}} call in
> {{compiler/cpp/src/thrift/generate/t_delphi_generator.cc}}. The "only depends
> on kernel32.dll" wording in {{doc/ReleaseManagement.md}} predates that call.
> _Drafted with AI assistance (Claude Opus 5); reviewed and posted by Jens
> Geyer._
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