Build failed with custom opencv on RockyLinux

[d0m1n1kr]

The build failed with the following error:

  error occurred: Command "c++" "-O3" "-ffunction-sections" "-fdata-sections" "-fPIC" "-gdwarf-4" "-fno-omit-frame-pointer" "-m64" "-I" "/home/dominik/.cargo/registry/src/index.crates.io-6f17d22bba15001f/opencv-0.88.1/src_cpp" "-I" "/home/dominik/rust-imager/target/debug/build/opencv-7c08d579b87f9d27/out" "-I" "." "-I" "/usr/local/include/opencv4" "-Wall" "-Wextra" "-std=c++14" "-Wno-deprecated-declarations" "-Wno-deprecated-copy" "-Wno-unused-parameter" "-Wno-sign-compare" "-Wno-comment" "-Wno-unused-variable" "-Wno-ignored-qualifiers" "-Wno-return-type-c-linkage" "-Wno-overloaded-virtual" "-o" "/home/dominik/rust-imager/target/debug/build/opencv-7c08d579b87f9d27/out/04cdb4ef15dc4ab0-freetype.o" "-c" "/home/dominik/rust-imager/target/debug/build/opencv-7c08d579b87f9d27/out/freetype.cpp" with args "c++" did not execute successfully (status code exit status: 1).

refering to

  cargo:warning=/home/dominik/rust-imager/target/debug/build/opencv-7c08d579b87f9d27/out/freetype.cpp: In function ‘void cv_freetype_FreeType2_loadFontData_charX_size_t_int(cv::freetype::FreeType2*, void**, size_t, int, ResultVoid*)’:
  cargo:warning=/home/dominik/rust-imager/target/debug/build/opencv-7c08d579b87f9d27/out/freetype.cpp:25:30: error: variable or field ‘ret_1’ declared void
  cargo:warning=   25 |                         void ret_1 = ;
  cargo:warning=      |                              ^~~~~
  cargo:warning=/home/dominik/rust-imager/target/debug/build/opencv-7c08d579b87f9d27/out/freetype.cpp:25:38: error: expected primary-expression before ‘;’ token
  cargo:warning=   25 |                         void ret_1 = ;
  cargo:warning=      |                                      ^
  cargo:warning=/home/dominik/rust-imager/target/debug/build/opencv-7c08d579b87f9d27/out/freetype.cpp:27:28: error: ‘ret_1’ was not declared in this scope
  cargo:warning=   27 |                         Ok(ret_1, ocvrs_return);
  cargo:warning=      |                            ^~~~~
  cargo:warning=At global scope:

The generated source code of freetype.cpp is:

	void cv_freetype_FreeType2_loadFontData_charX_size_t_int(cv::freetype::FreeType2* instance, void** pBuf, size_t bufSize, int idx, ResultVoid* ocvrs_return) {
		try {
			char* pBuf_out = new char[1024]();
			instance->loadFontData(pBuf_out, bufSize, idx);
			*pBuf = ocvrs_create_string(pBuf_out);
			void ret_1 = ;
			delete[] pBuf_out;
			Ok(ret_1, ocvrs_return);
		} OCVRS_CATCH(ResultVoid, ocvrs_return);
	}

The signature of the loadFontData from the freetype.hpp file is

    CV_WRAP virtual void loadFontData(char* pBuf, size_t bufSize, int idx) = 0;

Obviously somethings goes wrong in code generation with the void** parameter.

When I remove the line from the freetype.hpp header file, it builds successfully.

1. Operating system
   Linux version 5.14.0-284.30.1.el9_2.x86_64 (mockbuild@iad1-prod-build001.bld.equ.rockylinux.org) (gcc (GCC) 11.3.1 20221121 (Red Hat 11.3.1-4), GNU ld version 2.35.2-37.el9) Added a few Mat functions and corresponding primitives #1 SMP PREEMPT_DYNAMIC Sat Sep 16 09:55:41 UTC 2023
2. The way you installed OpenCV: package, official binary distribution, manual compilation, etc.
   Build with current 4.8.1 sources (including contrib modules).

cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local -D OPENCV_GENERATE_PKGCONFIG=ON -D 
OPENCV_EXTRA_MODULES_PATH=../opencv_contrib-4.x/modules -D WITH_FREETYPE=ON ../opencv-4.x

4. OpenCV version
   4.8.1
5. rustc version (rustc --version)
   rustc 1.74.0 (79e9716c9 2023-11-13)
6. Attach the full output of the following command from your project directory:

   RUST_BACKTRACE=full cargo build -vv 2> build_log.txt > build_log.txt

   build_log.txt

[twistedfall]

Looks like you're using git version of opencv_contrib, not a release version, because this function doesn't exist in the latest 4.8.1 release: https://github.com/opencv/opencv_contrib/blob/4.8.1/modules/freetype/include/opencv2/freetype.hpp#L85

So to solve this, use the latest release version for opencv_contrib, but this problem will come up with the next release so I'll work on fixing it, thank you for the report and analysis!

[d0m1n1kr]

You are right. I used this tutorial to install the latest version and I thought the zip files include the latest tag, not the release branch.

[twistedfall]

This should now be fixed in 0.88.5