PCRE initialization error on alpine

[fredrikekre]

I get the following error on alpine:

WARNING: Error during initialization of module PCRE:
ErrorException("could not load library "libpcre2-8"
Error loading shared library libpcre2-8.so: No such file or directory")
fatal: error thrown and no exception handler available.
InitError(mod=:Sys, error=ErrorException("could not load library "libpcre2-8"
Error loading shared library libpcre2-8.so: No such file or directory"))
rec_backtrace at /julia-source/src/stackwalk.c:94
jl_throw at /julia-source/src/task.c:210
jl_module_run_initializer at /julia-source/src/toplevel.c:81
_julia_init at /julia-source/src/init.c:854
main at /julia-source/ui/repl.c:211
__libc_start_main at /lib/ld-musl-x86_64.so.1 (unknown line)

which happens after packing a tarball with make binary-dist and then unpacking. Julia runs perfectly fine in the build directory.

Dockerfile:

FROM alpine:3.9.3
RUN apk add --update git make tar gcc python gfortran g++ perl
WORKDIR /julia-source
RUN git clone --progress https://github.com/JuliaLang/julia.git .
RUN echo 'override USE_BINARYBUILDER_UNWIND=0' >> Make.user
RUN make -j4
RUN make release
RUN make binary-dist
RUN mkdir -p /julia && tar -C /julia --strip-components=1 -xzf julia*.tar.gz
CMD ["/julia/bin/julia"]

[ararslan]

I downloaded the BinaryBuilder PCRE2 v10.31 in an Alpine 3.8 Docker container, and using an old Julia build I had laying around (v1.2.0-DEV.448 from the beginning of March) I was able to dlopen("libpcre2-8.so"). That suggests to me that it isn't likely a problem with the library itself or how it was built. Maybe it's being installed in the wrong place so Julia doesn't know where to find it?

[ararslan]

I did an identical (or as much so as I could) build in an Ubuntu Docker container to compare ldd, objdump -p, etc. since I had a hunch that it could be an RPATH issue. Everything seems to be in order there, as far as I can tell...

@staticfloat, do you have any sagely debugging tips for us?

[fredrikekre]

Output of strace: https://gist.github.com/fredrikekre/7594317199e8139936e11408af8f2f8a

[ararslan]

open("/julia/bin/../lib/libpcre2-8", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory)

That isn't the right directory. You said WORKDIR /julia-source and cloned into ., so the root of the clone should be /julia-source, but it's looking in /julia. Furthermore, it should be looking for libpcre2-8 in lib/julia rather than lib.

[fredrikekre]

I unpacked into /julia, but you are right, it should look in /julia/bin/../lib/julia/libpcre2-8.

[staticfloat]

My best guess here is that the RPATH of julia itself is $ORIGIN/../lib, and the RPATH of libjulia is $ORIGIN:$ORIGIN/julia. This works fine on glibc (since the dlopen("libpcre2-8") is happening within libjulia, it uses the library's RPATH) but I wonder if musl instead pays attention only to the originating executable? An easy way to test this would be to set the julia binary's RPATH to be $ORIGIN/../lib:$ORIGIN/../lib/julia.