Add multi-module support to project infrastructure

This projects contains two Go modules, one in the root and one in the `docsgen` subfolder. More will be added. In order
to support checks on the supplemental modules in the project subfolders, it's necessary to configure the commands to run
from their path. This is passed to the task via the GO_MODULE_PATH environment variable. If this variable is not defined,
the default root module path is used as default, preserving the previous task behavior.

The workflows use a job matrix to allow easy configuration for any number of module paths and a dedicated parallel job
for each module.

Author: per1234

Diff for: .github/workflows/check-go-task.yml

@@ -50,10 +50,19 @@ jobs:
           echo "::set-output name=result::$RESULT"
 
   check-errors:
+    name: check-errors (${{ matrix.module.path }})
     needs: run-determination
     if: needs.run-determination.outputs.result == 'true'
     runs-on: ubuntu-latest
 
+    strategy:
+      fail-fast: false
+
+      matrix:
+        module:
+          - path: ./
+          - path: docsgen
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2
@@ -70,13 +79,24 @@ jobs:
           version: 3.x
 
       - name: Check for errors
+        env:
+          GO_MODULE_PATH: ${{ matrix.module.path }}
         run: task go:vet
 
   check-outdated:
+    name: check-outdated (${{ matrix.module.path }})
     needs: run-determination
     if: needs.run-determination.outputs.result == 'true'
     runs-on: ubuntu-latest
 
+    strategy:
+      fail-fast: false
+
+      matrix:
+        module:
+          - path: ./
+          - path: docsgen
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2
@@ -93,16 +113,27 @@ jobs:
           version: 3.x
 
       - name: Modernize usages of outdated APIs
+        env:
+          GO_MODULE_PATH: ${{ matrix.module.path }}
         run: task go:fix
 
       - name: Check if any fixes were needed
         run: git diff --color --exit-code
 
   check-style:
+    name: check-style (${{ matrix.module.path }})
     needs: run-determination
     if: needs.run-determination.outputs.result == 'true'
     runs-on: ubuntu-latest
 
+    strategy:
+      fail-fast: false
+
+      matrix:
+        module:
+          - path: ./
+          - path: docsgen
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2
@@ -122,13 +153,24 @@ jobs:
         run: go install golang.org/x/lint/golint@latest
 
       - name: Check style
+        env:
+          GO_MODULE_PATH: ${{ matrix.module.path }}
         run: task --silent go:lint
 
   check-formatting:
+    name: check-formatting (${{ matrix.module.path }})
     needs: run-determination
     if: needs.run-determination.outputs.result == 'true'
     runs-on: ubuntu-latest
 
+    strategy:
+      fail-fast: false
+
+      matrix:
+        module:
+          - path: ./
+          - path: docsgen
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v2
@@ -145,6 +187,8 @@ jobs:
           version: 3.x
 
       - name: Format code
+        env:
+          GO_MODULE_PATH: ${{ matrix.module.path }}
         run: task go:format
 
       - name: Check formatting

Diff for: .github/workflows/test-go-task.yml

@@ -12,17 +12,17 @@ on:
     paths:
       - ".github/workflows/test-go-task.ya?ml"
       - "codecov.ya?ml"
-      - "go.mod"
-      - "go.sum"
+      - "**/go.mod"
+      - "**/go.sum"
       - "Taskfile.ya?ml"
       - "**.go"
       - "**/testdata/**"
   pull_request:
     paths:
       - ".github/workflows/test-go-task.ya?ml"
       - "codecov.ya?ml"
-      - "go.mod"
-      - "go.sum"
+      - "**/go.mod"
+      - "**/go.sum"
       - "Taskfile.ya?ml"
       - "**.go"
       - "**/testdata/**"
@@ -54,15 +54,21 @@ jobs:
           echo "::set-output name=result::$RESULT"
 
   test:
+    name: test (${{ matrix.module.path }} - ${{ matrix.operating-system }})
     needs: run-determination
     if: needs.run-determination.outputs.result == 'true'
 
     strategy:
+      fail-fast: false
+
       matrix:
         operating-system:
           - ubuntu-latest
           - windows-latest
           - macos-latest
+        module:
+          - path: ./
+            codecov-flags: unit
 
     runs-on: ${{ matrix.operating-system }}
 
@@ -82,12 +88,14 @@ jobs:
           version: 3.x
 
       - name: Run tests
+        env:
+          GO_MODULE_PATH: ${{ matrix.module.path }}
         run: task go:test
 
       - name: Send unit tests coverage to Codecov
         if: runner.os == 'Linux'
         uses: codecov/codecov-action@v2
         with:
-          file: ./coverage_unit.txt
-          flags: unit
+          file: ${{ matrix.module.path }}coverage_unit.txt
+          flags: ${{ matrix.module.codecov-flags }}
           fail_ci_if_error: ${{ github.repository == 'arduino/arduino-lint' }}

Diff for: Taskfile.yml

@@ -8,8 +8,19 @@ vars:
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/release-go-task/Taskfile.yml
   PROJECT_NAME: "arduino-lint"
   DIST_DIR: "dist"
+  # Path of the project's primary Go module:
+  DEFAULT_GO_MODULE_PATH: ./
   DEFAULT_GO_PACKAGES:
-    sh: echo $(go list ./... | grep --invert-match 'github.com/arduino/arduino-lint/internal/rule/schema/schemadata' | tr '\n' ' ')
+    sh: |
+      echo $( \
+        cd {{default .DEFAULT_GO_MODULE_PATH .GO_MODULE_PATH}} \
+        && \
+        go list ./... | \
+          grep --invert-match 'github.com/arduino/arduino-lint/internal/rule/schema/schemadata' | \
+            tr '\n' ' ' \
+        || \
+        echo '"ERROR: Unable to discover Go packages"' \
+      )
   # build vars
   COMMIT:
     sh: echo "$(git log --no-show-signature -n 1 --format=%h)"
@@ -134,6 +145,7 @@ tasks:
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/go-task/Taskfile.yml
   go:build:
     desc: Build the Go code
+    dir: "{{.DEFAULT_GO_MODULE_PATH}}"
     cmds:
       - go build -v {{.LDFLAGS}}
 
@@ -150,12 +162,14 @@ tasks:
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-go-task/Taskfile.yml
   go:fix:
     desc: Modernize usages of outdated APIs
+    dir: "{{default .DEFAULT_GO_MODULE_PATH .GO_MODULE_PATH}}"
     cmds:
       - go fix {{default .DEFAULT_GO_PACKAGES .GO_PACKAGES}}
 
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-go-task/Taskfile.yml
   go:format:
     desc: Format Go code
+    dir: "{{default .DEFAULT_GO_MODULE_PATH .GO_MODULE_PATH}}"
     cmds:
       - go fmt {{default .DEFAULT_GO_PACKAGES .GO_PACKAGES}}
 
@@ -172,6 +186,7 @@ tasks:
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-go-task/Taskfile.yml
   go:lint:
     desc: Lint Go code
+    dir: "{{default .DEFAULT_GO_MODULE_PATH .GO_MODULE_PATH}}"
     cmds:
       - |
         if ! which golint &>/dev/null; then
@@ -186,6 +201,7 @@ tasks:
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/test-go-task/Taskfile.yml
   go:test:
     desc: Run unit tests
+    dir: "{{default .DEFAULT_GO_MODULE_PATH .GO_MODULE_PATH}}"
     cmds:
       - |
         go test \
@@ -208,6 +224,7 @@ tasks:
   # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/assets/check-go-task/Taskfile.yml
   go:vet:
     desc: Check for errors in Go code
+    dir: "{{default .DEFAULT_GO_MODULE_PATH .GO_MODULE_PATH}}"
     cmds:
       - go vet {{default .DEFAULT_GO_PACKAGES .GO_PACKAGES}}