Cabal suddenly stopped building my project. Nothing much changed in the project itself since the last successful build, I guess only OS updates were installed.

The error I get on cabal v2-build is:

Undefined symbols for architecture x86_64:
  "_u_errorName_70", referenced from:
      ___hs_u_errorName in libHStxt-c-0.7.1.0-21406b30.a(text_icu.o)
  "_ucnv_close_70", referenced from:
      ___hs_ucnv_close in libHStxt-c-0.7.1.0-21406b30.a(text_icu.o)
  "_ucnv_fromUChars_70", referenced from:
      ___hs_ucnv_fromUChars in libHStxt-c-0.7.1.0-21406b30.a(text_icu.o)
  "_ucnv_getMaxCharSize_70", referenced from:
      ___get_max_bytes_for_string in libHStxt-c-0.7.1.0-21406b30.a(text_icu.o)
  "_ucnv_open_70", referenced from:
      ___hs_ucnv_open in libHStxt-c-0.7.1.0-21406b30.a(text_icu.o)
  "_ucnv_setFallback_70", referenced from:
      ___hs_ucnv_setFallback in libHStxt-c-0.7.1.0-21406b30.a(text_icu.o)
  "_ucnv_toUChars_70", referenced from:
      ___hs_ucnv_toUChars in libHStxt-c-0.7.1.0-21406b30.a(text_icu.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
`gcc' failed in phase `Linker'. (Exit code: 1)

Additionally, cabal repl stopped working as well:

<command line>: dlopen(/Users/user/.cabal/store/ghc-8.10.7/lib/libHStxt-c-0.7.1.0-21406b30-ghc8.10.7.dylib, 0x0005): Library not loaded: '/usr/local/opt/icu4c/lib/libicuuc.70.dylib'
  Referenced from: '/Users/user/.cabal/store/ghc-8.10.7/lib/libHStxt-c-0.7.1.0-21406b30-ghc8.10.7.dylib'
  Reason: tried: '/usr/local/opt/icu4c/lib/libicuuc.70.dylib' (no such file), '/usr/local/lib/libicuuc.70.dylib' (no such file), '/usr/lib/libicuuc.70.dylib' (no such file), '/usr/local/Cellar/icu4c/71.1/lib/libicuuc.70.dylib' (no such file), '/usr/local/lib/libicuuc.70.dylib' (no such file), '/usr/lib/libicuuc.70.dylib' (no such file)
Error: cabal: repl failed for exe:appname from
appname-1.0.0

I am on ghc 8.10.7, macOS Monterey 12.6.1 and cabal --version outputs

cabal-install version 3.8.1.0
compiled using version 3.8.1.0 of the Cabal library

Version of icu4c is 71.1, it is installed using brew.

How could I make the project compile successfully again?

CodePudding user response：

Well, it looks like the text-icu package got built against icu4u version 70, and then your system upgraded to version 71. Unless you feel like downgrading icu4u, you should try deleting the package store (that is, ~/.cabal/store/ghc-<version>/). The next run of cabal v2-build in your project will then go and rebuild all its dependencies, including the packages rendered "stale" by your system upgrade. Note that deleting the store may break installed executables.