[package] Tesseract/5.0.0: GCC Requirement too restrictive

I am working to compile the tesseract library into binaries for deployment on various Linux distros (with Ubuntu 18.04+ as my primary target right now).

The tesseract package (versions >=5.0.0) uses too restrictive of a GCC version (9+) to support C++17, when GCC 7 supports the C++17 standard (see references below). I have tried many different combinations of docker images/compilers and cannot produce a binary that “just works” on Ubuntu 18.04 due to GLIBC/CXX issues.

For reference:

• GCC C++17 standard support
• Clang C++ Standard support - seems full support is around clang ~7
• Visual Studio C++ Standard Support

I’ve tried a combination of different solutions to target Ubuntu 18.04 (with glibc 2.27):

• Conanio/gcc9 - glibc (2.30)
• Conanio/gcc8 - glibc (2.27) - fails to meet tesseract conanfile min gcc >=9 criteria, likely would work to meet needs
• Conanio/gcc7 - glibc (2.26) - fails to meet tesseract conanfile min gcc >= 9 criteria, likely would work to meed needs
• Conanio/clang7 - glibc (2.28), glibc too new and won’t be compatible with target glibc
• Using various centos images with upgrading the gcc to version 9.0 (GLIBC compatibility issues gone, but GLIBCXX compatibility issues)

Package and Environment Details (include every applicable attribute)

• Package Name/Version: tesseract/5.0.0
• Operating System+version: Linux Ubuntu 18.04
• Compiler+version: GCC 9
• Docker image: conanio/gcc9
• Conan version: conan 1.18.0
• Python version: Python 3.7.4

Conan profile (output of conan profile show default or conan profile show <profile> if custom profile is in use)

Not using a custom profile

Steps to reproduce (Include if Applicable)

1. Use docker to build lightweight project that uses tesseract in conanio/gcc9, builds against GLIBC 2.30
2. docker cp the binaries to an ubuntu:18.04 image, uses GLIBC
3. Run ldd /path/to/binary to confirm GLIBC/GLIBCXX compatiblity issues

Logs (Include/Attach if Applicable)

ldd result on Ubuntu 18.04 for binary built with conanio/gcc9

# ldd libocr.so
./libocr.so: /lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.29' not found (required by ./libocr.so)
./libocr.so: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: version `GLIBCXX_3.4.26' not found (required by ./libocr.so)
	linux-vdso.so.1 (0x00007fffb9d83000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f8c536f6000)
	libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f8c5336d000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f8c5314e000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f8c52db0000)
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f8c529bf000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f8c54de5000)
	libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f8c527a7000)

[brandonmkunkel]

Submitted PR for the downgrade https://github.com/conan-io/conan-center-index/pull/9682

[brandonmkunkel]

Found Github Issue from the tesseract source repository talking about compiler constraints. Seems the maintainers accept gcc 7 as the minimal version for their build processes. Now I just need to confirm on my PR (work in progress) that this gcc version is compatible with the conan package’s dependencies with local testing.

https://github.com/tesseract-ocr/tesseract/issues/3210#issuecomment-774599019