Multi-OS build matrix not working

Environments
1

Can someone enlighten me as to why the following build matrix is not producing any macOS builds (but still attempting to build on Linux)?

language: cpp

env:
  LINUX_DEPS="cmake libopencv-dev libopencv-contrib-dev libopencv-imgcodecs-dev libprotobuf-dev protobuf-compiler qtbase5-dev qtdeclarative5-dev qtmultimedia5-dev qtquickcontrols2-5-dev"
  MACOS_DEPS="cmake opencv protobuf qt"

matrix:
  include:
    # ubuntu lacks dnn support in OpenCV
    #- os: linux
    #  dist: bionic
    #  compiler: clang
    - os: osx
      compiler: clang

before_install:
  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then sudo apt-get update -y; fi
  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then sudo apt-get install -y $LINUX_DEPS; fi
  - if [ "$TRAVIS_OS_NAME" = "osx" ]; then brew install $MACOS_DEPS; fi

jobs:
  include:
    - stage: lint
      script:
        - make format
    - stage: build
      script:
        - make build

stages:
  #- lint
  - build

A misbehaving build with that config can be found at: https://travis-ci.org/raymanfx/seraphim/builds/564598607.
I have been following the docs at https://docs.travis-ci.com/user/multi-os/#example-multi-os-build-matrix, but the approach does not appear to work out for me.

2

You have both matrix and jobs, which are aliases of each other, and only the latter is effective.

3

Thank you very much, I was not aware of that.
Two more questions: I modified my config like this:

language: cpp

env:
LINUX_DEPS=“cmake libopencv-dev libopencv-contrib-dev libopencv-imgcodecs-dev libprotobuf-dev protobuf-compiler qtbase5-dev qtdeclarative5-dev qtmultimedia5-dev qtquickcontrols2-5-dev”
MACOS_DEPS=“cmake opencv protobuf qt”

matrix:
  include:
    # ubuntu lacks dnn support in OpenCV
    #- os: linux
    #  dist: bionic
    #  compiler: clang
    #  stage: lint
    #    script:
    #      - make format
    #  stage: build
    #    script:
    #      - make build
    - os: osx
      compiler: clang
      stage: lint
        script:
          - make format
      stage: build
        script:
          - make build

before_install:
  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then sudo apt-get update -y; fi
  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then sudo apt-get install -y $LINUX_DEPS; fi
  - if [ "$TRAVIS_OS_NAME" = "osx" ]; then brew install $MACOS_DEPS; fi

stages:
  #- lint
  - build

Is there a way to make the two stages expand to every matrix entry so I don’t have to specify them for each os/dist?

Furthermore, a job with that config just failed: https://travis-ci.org/raymanfx/seraphim/jobs/564653333. Any idea why the “brew install” command returned exit code 1? I can’t seem to spot the point where the error occured.