Could not use custom namespace on Boost 1.89.0: Unable to find file or target named boost_align

[uilianries]

Hello!

I am opening this issue as a reference to conan-io/conan-center-index#28978

An error was reported when trying to use Boost custom namespace, but of course, it could be a bug in the Conan recipe.

Still, I tried to build from scratch without Conan, and I reached the following steps:

#!/bin/bash

BOOST_VERSION=1_89_0
BOOST_BASE_VERSION=$(echo ${BOOST_VERSION} | tr _ .)
MYBOOST_DIR=/tmp/boost-${BOOST_BASE_VERSION}/myboost
INSTALL_DIR=/tmp/boost-${BOOST_BASE_VERSION}/install

set -ex

wget https://archives.boost.io/release/${BOOST_BASE_VERSION}/source/boost_${BOOST_VERSION}.tar.bz2
tar -xjf boost_${BOOST_VERSION}.tar.bz2
cd boost_${BOOST_VERSION}

./bootstrap.sh --with-toolset=gcc
./b2 tools/bcp

rm -rf ${MYBOOST_DIR}
mkdir -p ${MYBOOST_DIR}
./dist/bin/bcp --boost=. --namespace=myboost \
  align atomic charconv chrono container context contract coroutine \
  date_time exception fiber filesystem graph iostreams json \
  locale log math nowide process program_options random regex \
  serialization stacktrace test thread timer type_erasure url wave \
  config build boost_install headers \
  ${MYBOOST_DIR}

cd ${MYBOOST_DIR}
./bootstrap.sh --with-toolset=gcc

./b2 \
  toolset=gcc \
  variant=release \
  link=static \
  threading=multi \
  cxxstd=17 \
  --prefix=${INSTALL_DIR} \
  install

However, in the final steps, when running b2 in the new subset folder, I have:

error: Unable to find file or target named
error:     '/boost/align//boost_align'
error: referred to from project at
error:     '/tmp/boost-1.89.0/myboost/libs/atomic/build'

You can read my full log here: boost-1.89.0-build-namespace.log

It seems to be related to the modular Boost, causing a missing dependency. But as I'm not sure about it, I opened this issue first to get some support on this case.

Environment

Boost version: 1.89.0
OS: GNU/Linux 6.8.0
Distro: Ubuntu 24.04
Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.2) 11.4.0

Please, let me know if you need extra information that can help to clarify the case. Regards!