Slack integration doesn't support Windows platform

Orb version: circleci/slack@3.4.2

Error message: failed to start cmd: exec: "/bin/bash": file does not exist

Is it possible to workaround this issue using artifacts and sending all Slack notifications from a docker image?

You can indeed use build artifacts to pass the outcome of a job from a Windows workflow to a Linux workflow and then trick the Slack orb into reporting the status of the Windows workflow from the Linux workflow by overriding the environment variables it reads from. This is a very ugly solution, but I personally prefer it to having no Slack notifications at all on Windows. Another option would be to ditch the Slack orb altogether and hit the Slack API directly. Any feedback folks have on improving this workaround is quite welcome.

version: 2.1
  slack: circleci/slack@4.4.0
  windows: circleci/windows@2.4.0
    executor: windows/default
      - run:
          name: Make directory for job metadata.
          command: mkdir C:/tmp/job_metadata
          shell: bash.exe
      - run:
          name: Write current job URL.
          command: echo "$CIRCLE_BUILD_URL" > C:/tmp/job_metadata/build_url.txt
          shell: bash.exe
      - run:
          when: on_fail
          name: Write job exit code 1 for failure.
          command: echo 1 > C:/tmp/job_metadata/exit_code.txt
          shell: bash.exe
      - run:
          when: on_success
          name: Write job exit code 0 for success.
          command: echo 0 > C:/tmp/job_metadata/exit_code.txt
          shell: bash.exe
      - store_artifacts:
          path: /tmp/job_metadata
          destination: build-job-metadata
      - image: cimg/base:stable
    resource_class: small
      - run:
          name: Download any job metadata artifacts for latest completed job on this branch.
          command: >
            --header "Content-Type: application/json"
            --header "Accept: application/json"
            --header "Circle-Token: $CIRCLE_TOKEN"
            "<< pipeline.project.type >>/$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME/latest/artifacts?branch=$CIRCLE_BRANCH&filter=completed" |
            grep --only-matching 'https://[^"]*build-job-metadata[^"]*' |
            xargs -I url wget --header "Circle-Token: $CIRCLE_TOKEN" url
      - run:
          name: Overwrite CIRCLE_JOB environment variable with build.
          command: echo export CIRCLE_JOB=build >> $BASH_ENV
      - run:
          name: Overwrite CIRCLE_BUILD_URL environment variable from prior job metadata.
          command: echo export CIRCLE_BUILD_URL=$(<build_url.txt) >> $BASH_ENV
      - run:
          name: Exit with code from prior job metadata.
          command: exit $(<exit_code.txt)
      - slack/notify:
          event: fail
          template: basic_fail_1
      - slack/notify:
          event: pass
          template: basic_success_1
      - build
  # Take advantage of the fact that free CircleCI accounts are limited to
  # running one workflow at a time. If you are on a paid account, these
  # workflows will instead run in parallel. Consider submitting a pull request
  # to the Slack orb to use the bash.exe shell on Windows, using
  #, or using the CircleCI API to
  # wait for the build workflow to complete.
      - notify:
            # a context that defines the CIRCLE_TOKEN environment variable
            # to be a CircleCI API token for your project with Admin scope
            - circleci-api-admin
            # a context that defines the SLACK_ACCESS_TOKEN and SLACK_DEFAULT_CHANNEL
            # environment variables as specified by
            - slack