[PATCH v3] Travis: also test on 32-bit Linux

From: Johannes Schindelin <johannes.schindelin@gmx.de>

When Git v2.9.1 was released, it had a bug that showed only on Windows and on 32-bit systems: our assumption that `unsigned long` can hold 64-bit values turned out to be wrong.

This could have been caught earlier if we had a Continuous Testing set up that includes a build and test run on 32-bit Linux.

Let's do this (and take care of the Windows build later). This patch asks Travis CI to install a Docker image with 32-bit libraries and then goes on to build and test Git using this 32-bit setup.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
---

Hi,

when I looked into the 32-bit/line-log issue [1], I realized that my
proposed docker setup is not ideal for local debugging. Here is an
approach that I think is better. I changed the following:
    - disable sudo as it is not required for the Travis job
    - keep all docker commands in the .travis.yml
    - add option to run commands inside docker with the same UID as the
      host user to make output files accessible
    - pass environment variables directly to the docker container

Sorry for the back and forth.

Cheers, Lars

[1] http://public-inbox.org/git/2205F1A7-A694-4F40-B994-D68C3947F2BB@gmail.com/

Notes:
    Base Ref: master
    Web-Diff: https://github.com/larsxschneider/git/commit/a6fe1def16
    Checkout: git fetch https://github.com/larsxschneider/git travisci/linux32-v3 && git checkout a6fe1def16

    Interdiff (v2..v3):

    diff --git a/.travis.yml b/.travis.yml
    index fd60fd8328..591cc57b80 100644
    --- a/.travis.yml
    +++ b/.travis.yml
    @@ -41,13 +41,25 @@ matrix:
       include:
         - env: Linux32
           os: linux
    -      sudo: required
           services:
             - docker
           before_install:
             - docker pull daald/ubuntu32:xenial
           before_script:
    -      script: ci/run-linux32-build.sh daald/ubuntu32:xenial
    +      script:
    +        - >
    +          docker run
    +          --interactive
    +          --env DEFAULT_TEST_TARGET
    +          --env GIT_PROVE_OPTS
    +          --env GIT_TEST_OPTS
    +          --env GIT_TEST_CLONE_2GB
    +          --volume "${PWD}:/usr/src/git"
    +          daald/ubuntu32:xenial
    +          /usr/src/git/ci/run-linux32-build.sh $(id -u $USER)
    +        # Use the following command to debug the docker build locally:
    +        # $ docker run -itv "${PWD}:/usr/src/git" --entrypoint /bin/bash daald/ubuntu32:xenial
    +        # root@container:/# /usr/src/git/ci/run-linux32-build.sh
         - env: Documentation
           os: linux
           compiler: clang
    diff --git a/ci/run-linux32-build.sh b/ci/run-linux32-build.sh
    index 13c184d41c..f7a3434985 100755
    --- a/ci/run-linux32-build.sh
    +++ b/ci/run-linux32-build.sh
    @@ -1,31 +1,30 @@
     #!/bin/sh
     #
    -# Build and test Git in a docker container running a 32-bit Ubuntu Linux
    +# Build and test Git in a 32-bit environment
     #
     # Usage:
    -#   run-linux32-build.sh [container-image]
    +#   run-linux32-build.sh [host-user-id]
     #

    -CONTAINER="${1:-daald/ubuntu32:xenial}"
    -
    -sudo docker run --interactive --volume "${PWD}:/usr/src/git" "$CONTAINER" \
    -    /bin/bash -c 'linux32 --32bit i386 sh -c "
    -    : update packages &&
    +# Update packages to the latest available versions
    +linux32 --32bit i386 sh -c '
         apt update >/dev/null &&
         apt install -y build-essential libcurl4-openssl-dev libssl-dev \
    -        libexpat-dev gettext python >/dev/null &&
    +        libexpat-dev gettext python >/dev/null
    +' &&
    +
    +# If this script runs inside a docker container, then all commands are
    +# usually executed as root. Consequently, the host user might not be
    +# able to access the test output files.
    +# If a host user id is given, then create a user "ci" with the host user
    +# id to make everything accessible to the host user.
    +HOST_UID=$1 &&
    +CI_USER=$USER &&
    +test -z $HOST_UID || (CI_USER="ci" && useradd -u $HOST_UID $CI_USER) &&

    -    : build and test &&
    +# Build and test
    +linux32 --32bit i386 su -m -l $CI_USER -c '
         cd /usr/src/git &&
    -    export DEFAULT_TEST_TARGET='$DEFAULT_TEST_TARGET' &&
    -    export GIT_PROVE_OPTS=\"'"$GIT_PROVE_OPTS"'\" &&
    -    export GIT_TEST_OPTS=\"'"$GIT_TEST_OPTS"'\" &&
    -    export GIT_TEST_CLONE_2GB='$GIT_TEST_CLONE_2GB' &&
         make --jobs=2 &&
    -    make --quiet test || (
    -
    -    : make test-results readable to non-root user on TravisCI &&
    -    test '$TRAVIS' &&
    -    find t/test-results/ -type f -exec chmod o+r {} \; &&
    -    false )
    -"'
    +    make --quiet test
    +'

    \0

 .travis.yml             | 21 +++++++++++++++++++++
 ci/run-linux32-build.sh | 30 ++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)
 create mode 100755 ci/run-linux32-build.sh