Unable to build multiprocess using depends (macOS 12.6, Intel) #26200

Since I'm having some difficulty installing libmultiprocess directly (https://github.com/chaincodelabs/libmultiprocess/issues/75), I'm trying the depends route instead.

When I install capnp via homebrew, and then libmultiprocess via depends, I end up with version mismatch errors when calling make (on the main project):

/usr/local/include/mp/proxy.capnp.h:13:2: error: "Version mismatch between generated code and library headers.  You must use the same version of the Cap'n Proto compiler and library."

If on the other hand I brew uninstall capnp and then build libmultiprocess via depends, I get a different error:

execlp failed: No such file or directory
libc++abi: terminating with uncaught exception of type std::runtime_error: Invoking /usr/local/bin/capnp failed
execlp failed: No such file or directory
libc++abi: terminating with uncaught exception of type std::runtime_error: Invoking /usr/local/bin/capnp failed
/bin/sh: line 1: 84357 Abort trap: 6           /usr/local/bin/mpgen '.' '.' ipc/capnp/init.capnp
/bin/sh: line 1: 84356 Abort trap: 6           /usr/local/bin/mpgen '.' '.' ipc/capnp/echo.capnp
make[2]: *** [ipc/capnp/init.capnp.h] Error 134

This was on top a recent master commit (5558d2f5496d8fe1c16f9edd1ef395fcd842e6fb).

cc @ryanofsky

I can provide more detailed logs if you can't reproduce. Perhaps this is related to https://github.com/chaincodelabs/libmultiprocess/issues/75 so I'll try again when that's fixed.

Failed to reproduce the issue on macOS 12.6 (21G115, Intel), the master branch (291e363ce500e492475c4ccd189ea1d031c43613), no Homebrew's capnp installed:

% make -C depends NO_QT=1 MULTIPROCESS=1
% ./autogen.sh
% ./configure CONFIG_SITE=$PWD/depends/x86_64-apple-darwin21.6.0/share/config.site
% make clean
% make

Tried again on that slightly newer master commit, with git clean -dfx and ccache -C for good measure.

make -C depends -j17 NO_QT=1 MULTIPROCESS=1 NO_UPNP=1 NO_NATPMP=1

• log of the capnproto & multiprocess part.

CONFIG_SITE=$PWD/depends/x86_64-apple-darwin21.6.0 ./configure --enable-suppress-external-warnings --disable-bench --disable-fuzz-binary --with-gui --enable-external-signer --enable-multiprocess

(in my experience the --enable-multiprocess is necessary or it defaults to no)

• config.log

 make -j17
Making all in src
  CXX      bitcoind-bitcoind.o
...
  GEN      ipc/capnp/echo.capnp.h
execlp failed: No such file or directory
libc++abi: terminating with uncaught exception of type std::runtime_error: Invoking /usr/local/bin/capnp failed
/bin/sh: line 1: 74515 Abort trap: 6           /usr/local/bin/mpgen '.' '.' ipc/capnp/echo.capnp
make[2]: *** [ipc/capnp/echo.capnp.h] Error 134
make[2]: *** Waiting for unfinished jobs....
  CCLD     libsecp256k1_precomputed.la
  CCLD     libsecp256k1.la
make[1]: *** [all-recursive] Error 1
make: *** [all-recursive] Error 1

(in my experience the --enable-multiprocess is necessary or it defaults to no)

CONFIG_SITE=$PWD/depends/x86_64-apple-darwin21.6.0 must be CONFIG_SITE=$PWD/depends/x86_64-apple-darwin21.6.0/share/config.site

Ah, that's a confusing failure mode...

ALLOW_HOST_PACKAGES=1 doesn't seem to let me use the Homebrew version of QT, but that's a separate issue:

checking for Qt5Core >= 5.11.3... no
configure: error: Qt5Core >= 5.11.3 not found

(I have qt@5: stable 5.15.6)

Maybe as a followup it would be good to make the depends system have an explicit error message if the CONFIG_SITE variable is set and is not a file path (! test -f).

If there are any other ideas about how to make error messages better or prevent errors from happening, definitely feel free to post them or open new issues.