Target specific scripts in "Check Scripts" template

per1234 · per1234 · commit ad800ef0815e · 2024-10-15T06:45:09.000-07:00
Background
----------

Previously, the approach taken shell script tasks was to recursively search the entire repository for shell scripts.
There were several problems with that system:

The `-regextype` flag used in the `find` commands of the `shell:check` and `shell:check-mode` tasks is not supported by
the BSD/macOS version of `find`, meaning the tasks would fail if a contributor using a macOS machine tried to run them:

```
find: -regextype: unknown primary or operator
```

The `shell:check` and `shell:check-mode` tasks only provided coverage for files with `.sh` and `.bash` file extensions,
whereas the practice of omitting a file extension on shell scripts is unfortunately quite common.

There was no obvious way to exclude paths of externally maintained files from coverage by the `shell:format` task.

Alternative Solutions
---------------------

The first of the problems listed above could be overcome by configuring the tasks to adjust the `find` commands to use
different flags depending on the operating system of the machine.

The second could be overcome by using `shfmt --files` (which searches recursively for shell scripts by checking for the
presence of a shebang inside files and outputs a list of the paths) as a replacement for `find`.

The third could be overcome by documenting the usage of shfmt's poorly advertised feature of ignoring the paths assigned
an `ignore` attribute in the .editorconfig file.

Chosen Solution
---------------

After careful consideration, the decision was made to abandon the previous approach of attempting to automatically
discover script files and instead instead use the strategy of configuring the template with the specific paths of the
scripts to be checked for each project it is installed into. Although such an approach would not be appropriate in the
case of a check on files that tend to be present in greater abundance and regularly added and moved in a project, this
is not the case for shell scripts in Arduino projects. A project is more likely to contain a few scripts at most and
their paths tend to be reasonably stable.

Code Duplication in Workflow
----------------------------

In order to make it easier to interpret results, navigate logs, and reduce duration of workflow runs, a separate
workflow job is used for each of the distinct checks. Unfortunately it is necessary for the project maintainer to
configure the script paths redundantly in the matrix of each of the three jobs.

Intuitively we would expect this could be avoided by defining the paths at workflow scope via the env key. However, this
is not feasible due to the env context not being available for use in the jobs.&lt;job name&gt;.strategy.matrix key.

It is technically possible to accomplish this by adding a job that converts the data from the `env` context into a job
output (the `needs` context is available for use in the `matrix` key). However the significant increase in complexity
this would bring to the workflow outweighs the benefit of avoiding duplication.
diff --git a/.github/workflows/check-shell-task.yml b/.github/workflows/check-shell-task.yml
@@ -50,7 +50,7 @@ jobs:
           echo "result=$RESULT" >> $GITHUB_OUTPUT
 
   lint:
-    name: ${{ matrix.configuration.name }}
+    name: ${{ matrix.configuration.name }} (${{ matrix.script }})
     needs: run-determination
     if: needs.run-determination.outputs.result == 'true'
     runs-on: ubuntu-latest
@@ -75,6 +75,8 @@ jobs:
             # ShellCheck's "tty" output format is most suitable for humans reading the log.
             format: tty
             continue-on-error: false
+        script:
+          - etc/install.sh
 
     steps:
       - name: Set environment variables
@@ -114,15 +116,26 @@ jobs:
         continue-on-error: ${{ matrix.configuration.continue-on-error }}
         with:
           linters: gcc
-          run: task --silent shell:check SHELLCHECK_FORMAT=${{ matrix.configuration.format }}
+          # Due to a quirk of the "liskin/gh-problem-matcher-wrap" action, the entire command must be on a single line
+          # (instead of being broken into multiple lines for readability).
+          run: |
+            task --silent shell:check SCRIPT_PATH="${{ matrix.script }}" SHELLCHECK_FORMAT=${{ matrix.configuration.format }}
 
   formatting:
+    name: formatting (${{ matrix.script }})
     needs: run-determination
     if: needs.run-determination.outputs.result == 'true'
     runs-on: ubuntu-latest
     permissions:
       contents: read
 
+    strategy:
+      fail-fast: false
+
+      matrix:
+        script:
+          - etc/install.sh
+
     steps:
       - name: Set environment variables
         run: |
@@ -158,18 +171,30 @@ jobs:
           echo "${{ env.SHFMT_INSTALL_PATH }}" >> "$GITHUB_PATH"
 
       - name: Format shell scripts
-        run: task --silent shell:format
+        run: |
+          task \
+            --silent \
+            shell:format \
+            SCRIPT_PATH="${{ matrix.script }}"
 
       - name: Check formatting
         run: git diff --color --exit-code
 
   executable:
+    name: executable (${{ matrix.script }})
     needs: run-determination
     if: needs.run-determination.outputs.result == 'true'
     runs-on: ubuntu-latest
     permissions:
       contents: read
 
+    strategy:
+      fail-fast: false
+
+      matrix:
+        script:
+          - etc/install.sh
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
@@ -181,4 +206,8 @@ jobs:
           version: 3.x
 
       - name: Check for non-executable scripts
-        run: task --silent shell:check-mode
+        run: |
+          task \
+            --silent \
+            shell:check-mode \
+            SCRIPT_PATH="${{ matrix.script }}"
diff --git a/Taskfile.yml b/Taskfile.yml
@@ -396,73 +396,61 @@ tasks:
     cmds:
       - poetry run flake8 --show-source
 
+  # Parameter variables:
+  # - SCRIPT_PATH: path of the script to be checked.
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-shell-task/Taskfile.yml
   shell:check:
     desc: Check for problems with shell scripts
     cmds:
+      - |
+        if [[ "{{.SCRIPT_PATH}}" == "" ]]; then
+          echo "Path to script file must be passed to this task via the SCRIPT_PATH taskfile variable."
+          echo "See: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/check-shell-task.md#usage"
+          exit 1
+        fi
       - |
         if ! which shellcheck &>/dev/null; then
           echo "shellcheck not installed or not in PATH. Please install: https://github.com/koalaman/shellcheck#installing"
           exit 1
         fi
       - |
-        # There is something odd about shellcheck that causes the task to always exit on the first fail, despite any
-        # measures that would prevent this with any other command. So it's necessary to call shellcheck only once with
-        # the list of script paths as an argument. This could lead to exceeding the maximum command length on Windows if
-        # the repository contained a large number of scripts, but it's unlikely to happen in reality.
         shellcheck \
           --format={{default "tty" .SHELLCHECK_FORMAT}} \
-          $(
-            # The odd method for escaping . in the regex is required for windows compatibility because mvdan.cc/sh gives
-            # \ characters special treatment on Windows in an attempt to support them as path separators.
-            find . \
-              -path ".git" -prune -or \
-              \( \
-                -regextype posix-extended \
-                -regex '.*[.](bash|sh)' -and \
-                -type f \
-              \)
-          )
+          "{{.SCRIPT_PATH}}"
 
+  # Parameter variables:
+  # - SCRIPT_PATH: path of the script to be checked.
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-shell-task/Taskfile.yml
   shell:check-mode:
     desc: Check for non-executable shell scripts
     cmds:
       - |
-        EXIT_STATUS=0
-        while read -r nonExecutableScriptPath; do
-          # The while loop always runs once, even if no file was found
-          if [[ "$nonExecutableScriptPath" == "" ]]; then
-            continue
-          fi
-
-          echo "::error file=${nonExecutableScriptPath}::non-executable script file: $nonExecutableScriptPath";
-          EXIT_STATUS=1
-        done <<<"$(
-          # The odd approach to escaping `.` in the regex is required for windows compatibility because mvdan.cc/sh
-          # gives `\` characters special treatment on Windows in an attempt to support them as path separators.
-          find . \
-            -path ".git" -prune -or \
-            \( \
-              -regextype posix-extended \
-              -regex '.*[.](bash|sh)' -and \
-              -type f -and \
-              -not -executable \
-              -print \
-            \)
-        )"
-        exit $EXIT_STATUS
+        if [[ "{{.SCRIPT_PATH}}" == "" ]]; then
+          echo "Path to script file must be passed to this task via the SCRIPT_PATH taskfile variable."
+          echo "See: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/check-shell-task.md#usage"
+          exit 1
+        fi
+      - |
+        test -x "{{.SCRIPT_PATH}}"
 
+  # Parameter variables:
+  # - SCRIPT_PATH: path of the script to be formatted.
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-shell-task/Taskfile.yml
   shell:format:
     desc: Format shell script files
     cmds:
+      - |
+        if [[ "{{.SCRIPT_PATH}}" == "" ]]; then
+          echo "Path to script file must be passed to this task via the SCRIPT_PATH taskfile variable."
+          echo "See: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/check-shell-task.md#usage"
+          exit 1
+        fi
       - |
         if ! which shfmt &>/dev/null; then
           echo "shfmt not installed or not in PATH. Please install: https://github.com/mvdan/sh#shfmt"
           exit 1
         fi
-      - shfmt -w .
+      - shfmt -w "{{.SCRIPT_PATH}}"
 
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-mkdocs-task/Taskfile.yml
   website:check:
