Thanks for the git bisect hint!
The result:
98d813b92c26f0c93cefe21fe7768ca4f73d2d9a is the first bad commit
commit 98d813b92c26f0c93cefe21fe7768ca4f73d2d9a
Merge: 2f7c4a788c e5ec0e52f4
Author: Brad King
Date: Mon Jul 26 13:34:23 2021 +0000
Merge topic 'autouic-header-depends' into release-3.21
e5ec0e52f4 AUTOUIC: Fix generating of dependency rules for UI header files
Acked-by: Kitware Robot
Merge-request: !6380
Source/CMakeLists.txt | 2 +
Source/cmQtAutoGen.cxx | 36 +++++++++++++++
Source/cmQtAutoGen.h | 3 ++
Source/cmQtAutoGenInitializer.cxx | 53 +++++++++++-----------
Source/cmQtAutoGenInitializer.h | 2 +
Source/cmQtAutoGenerator.cxx | 37 ---------------
Source/cmQtAutoGenerator.h | 2 -
Source/cmQtAutoMocUic.cxx | 20 ++------
Source/cmQtAutoUicHelpers.cxx | 25 ++++++++++
Source/cmQtAutoUicHelpers.h | 20 ++++++++
.../QtAutogen/RerunUicOnFileChange/CMakeLists.txt | 3 ++
.../UicOnFileChange/CMakeLists.txt.in | 4 +-
.../RerunUicOnFileChange/UicOnFileChange/main.cpp | 4 +-
.../UicOnFileChange/subdir/mainwindowsubdir.ui.in | 7 +++
.../UicOnFileChange/subdir/subdircheck.cpp | 9 ++++
15 files changed, 144 insertions(+), 83 deletions(-)
create mode 100644 Source/cmQtAutoUicHelpers.cxx
create mode 100644 Source/cmQtAutoUicHelpers.h
create mode 100644 Tests/QtAutogen/RerunUicOnFileChange/UicOnFileChange/subdir/mainwindowsubdir.ui.in
create mode 100644 Tests/QtAutogen/RerunUicOnFileChange/UicOnFileChange/subdir/subdircheck.cp
Since this merge has to do with the autouic process - we are using AUTOUIC; and that reminds me that with 3.21 another peculiarity started in our project: For all targets created in a subdirectory, now all generated ui_xyz.h files are added to each targets’ (Visual Studio) project (all .ui files from all targets are included in all targets - altough each of them is only referenced in the source files of a single target - and that four times, once for each configured build type in the VS multi-config generator); before (i.e. with 3.20.x and less), they were not shown in the project at all. The addition of these files to the project seems mostly “cosmetical”, but probably has to do with being able to properly resolve dependencies?
The .ui files for the targets are in separate subfolders (one for each target), and the source files for each target only include those in the respective subfolder, and only the correct .h files for each single target are in the target- and configuration-specific subfolder in the build directory (e.g. if the target’s name is Test, they get created in Test_autogen/include_(Debug|Release|…) - so I’m not sure why CMake does add all ui_xyz.h files to all targets…