Use CMAKE_INSTALL_FULL_LIBDIR, CMAKE_INSTALL_FULL_INCLUDEDIR #1124
Conversation
Do not roll our own path contatenation, let's use GNUInstallDirs macros to do the work.
Issue
When `CMAKE_INSTALL_LIBDIR` and `CMAKE_INSTALL_INCLUDEDIR` are set to absolute paths, the `msgpack-c.pc` file generated by CMake improperly configures `libdir` and `includedir`. This leads to incorrect paths that prevent the compiler from locating necessary header and library files.
How to reproduce
Build and install `msgpack-c`.
```console
% cmake -S . -B ../msgpack-c.build -DCMAKE_INSTALL_LIBDIR=/tmp/local/lib -DCMAKE_INSTALL_INCLUDEDIR=/tmp/local/include
% cmake --build ../msgpack-c.build
% sudo cmake --install ../msgpack-c.build
```
Compile `example/simple_c.c` using installed msgpack-c. The following error happens because the linker cannot find paths provided by pkg-config.
```console
% export PKG_CONFIG_PATH=/tmp/local/lib/pkgconfig:$PKG_CONFIG_PATH
% gcc -o simple_c example/simple_c.c $(pkg-config --cflags --libs msgpack-c)
/usr/bin/ld: cannot find -lmsgpack-c: No such file or directory
collect2: error: ld returned 1 exit status
```
Expected
Successfully compile `example/simple_c.c` using installed msgpack-c. We can execute `simple_c` like the following.
```console
% gcc -o simple_c example/simple_c.c $(pkg-config --cflags --libs msgpack-c)
% ./simple_c
93 01 c3 a7 65 78 61 6d 70 6c 65
[1, true, "example"]
```
Explain the problem in detail
The generated `msgpack-c.pc` file does not handle absolute paths correctly. Here is the result of the incorrect configuration in `How to reproduce` section. In the following `msgpack-c.pc` file, `libdir` and `includedir` are showing unrecognized paths, leading to incorrect paths.
```console
% cat /tmp/local/lib/pkgconfig/msgpack-c.pc
prefix=/usr/local
exec_prefix=/usr/local
libdir=${prefix}//tmp/local/lib <- Here the path is wrong. We expected `/tmp/local/lib`
includedir=${prefix}//tmp/local/include <- Here the path is wrong. We expected `/tmp/local/include`
Name: MessagePack
Description: Binary-based efficient object serialization library
Version: 6.0.1
Libs: -L${libdir} -lmsgpack-c
Cflags: -I${includedir}
```
Solution
Modify the `CMakeLists.txt` file to ensure that `libdir` and `includedir` use absolute paths. This change addresses the issue by providing correct paths to the compiler and linker.
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@redboltz |
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I agree with @otegami concerns. This patch seems to work fine. but does not account in the possibility to let the users override Can we integrate https://github.com/jtojnar/cmake-snips/blob/master/CMakeScripts/JoinPaths.cmake into this build? (It is MIT-licensed)? |
I believe I have already done so in the following section: Lines 33 to 42 in a5c8a2c However, I think the issue lies in the following section. These header files are being installed without respecting our specified Lines 273 to 280 in a5c8a2c |
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I tried to fix the above problem at this PR #1125. |
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I'll check if the problem is fixed, unless we need to simplify the code (which might be difficult if we want to keep both relative/absolute names and prefix setting in the pkg-config file), we might not need/want this change anymore. |
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I was tracking a branch before this commit |
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New knowledge. This bug is not fixed in msgpack_c-6.0.2 When I patch msgpack-c using this patch, i no longer get the bug tracked here: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=279615 I do however still encounter knock on issues. Because of how msgpack-c resolves these paths, compiling binutils leads to the compile command: The relevant part of this command line is:
This empty include path argument consumes the following |
Do not roll our own path contatenation, let's use
GNUInstallDirs macros to do the work.