support skip ci in azure pipelines, and support it properly in github actions pipelines (#17561)

* support skip ci in azure pipelines

* [skip ci] example of a commit that skips CI

* example of a commit that does not skip CI

* fix github actions logic for ci skip handling

* [skip ci] example of a commit that skips CI for all pipelines

* example of a commit that does not skip CI for any pipeline

.github/workflows/ci_docs.yml

@@ -30,8 +30,9 @@ on:
 
 jobs:
   build:
+    # see D20210329T004830
     if: |
-      !contains(format('{0} {1}', github.event.head_commit.message, github.event.pull_request.title), '[skip ci]')
+      !contains(format('{0}', github.event.pull_request.title), '[skip ci]')
     strategy:
       fail-fast: false
       matrix:
@@ -50,6 +51,16 @@ jobs:
     steps:
       - name: 'Checkout'
         uses: actions/checkout@v2
+        with:
+          fetch-depth: 2
+
+      - name: 'Check whether to skip CI'
+        shell: bash
+        run: |
+          # see D20210329T004830
+          commitMsg=$(git log --no-merges -1 --pretty=format:"%s")
+          echo commitMsg: $commitMsg
+          echo $commitMsg | grep -v '\[skip ci\]'
 
       - name: 'Install build dependencies (macOS)'
         if: runner.os == 'macOS'

.github/workflows/ci_packages.yml

@@ -3,8 +3,9 @@ on: [push, pull_request]
 
 jobs:
   build:
+    # see D20210329T004830
     if: |
-      !contains(format('{0} {1}', github.event.head_commit.message, github.event.pull_request.title), '[skip ci]')
+      !contains(format('{0}', github.event.pull_request.title), '[skip ci]')
     strategy:
       fail-fast: false
       matrix:
@@ -19,6 +20,17 @@ jobs:
     steps:
       - name: 'Checkout'
         uses: actions/checkout@v2
+        with:
+          fetch-depth: 2
+
+      - name: 'Check whether to skip CI'
+        shell: bash
+        run: |
+          # see D20210329T004830
+          commitMsg=$(git log --no-merges -1 --pretty=format:"%s")
+          echo commitMsg: $commitMsg
+          echo $commitMsg | grep -v '\[skip ci\]'
+
       - name: 'Checkout csources'
         uses: actions/checkout@v2
         with:

azure-pipelines.yml

@@ -52,10 +52,20 @@ jobs:
   steps:
     - bash: git config --global core.autocrlf false
       displayName: 'Disable auto conversion to CRLF by git (Windows-only)'
-      condition: eq(variables['Agent.OS'], 'Windows_NT')
+      condition: and(succeeded(), eq(variables['Agent.OS'], 'Windows_NT'))
 
     - checkout: self
-      fetchDepth: 1
+      fetchDepth: 2 # see D20210329T004830
+
+    - bash: |
+        # D20210329T004830:here refs https://github.com/microsoft/azure-pipelines-agent/issues/2944
+        # `--no-merges` is needed to avoid merge commits which occur for PR's.
+        # $(Build.SourceVersionMessage) is not helpful
+        # nor is `github.event.head_commit.message` for github actions.
+        commitMsg=$(git log --no-merges -1 --pretty=format:"%s")
+        echo commitMsg: $commitMsg
+        echo $commitMsg | grep -v '\[skip ci\]' # fails if [skip ci] not in commit msg
+      displayName: 'Check whether to skip CI'
 
     - bash: git clone --depth 1 https://github.com/nim-lang/csources
       displayName: 'Checkout Nim csources'
@@ -73,7 +83,7 @@ jobs:
           echo_run sudo apt-fast install --no-install-recommends -yq \
             libcurl4-openssl-dev libgc-dev libsdl1.2-dev libsfml-dev valgrind libc6-dbg
       displayName: 'Install dependencies (amd64 Linux)'
-      condition: and(eq(variables['Agent.OS'], 'Linux'), eq(variables['CPU'], 'amd64'))
+      condition: and(succeeded(), eq(variables['Agent.OS'], 'Linux'), eq(variables['CPU'], 'amd64'))
 
     - bash: |
         set -e
@@ -113,11 +123,11 @@ jobs:
         echo_run chmod 755 bin/g++
 
       displayName: 'Install dependencies (i386 Linux)'
-      condition: and(eq(variables['Agent.OS'], 'Linux'), eq(variables['CPU'], 'i386'))
+      condition: and(succeeded(), eq(variables['Agent.OS'], 'Linux'), eq(variables['CPU'], 'i386'))
 
     - bash: brew install boehmgc make sfml
       displayName: 'Install dependencies (OSX)'
-      condition: eq(variables['Agent.OS'], 'Darwin')
+      condition: and(succeeded(), eq(variables['Agent.OS'], 'Darwin'))
 
     - bash: |
         set -e
@@ -130,7 +140,7 @@ jobs:
         echo_run echo '##vso[task.prependpath]$(System.DefaultWorkingDirectory)/dist/mingw64/bin'
 
       displayName: 'Install dependencies (Windows)'
-      condition: eq(variables['Agent.OS'], 'Windows_NT')
+      condition: and(succeeded(), eq(variables['Agent.OS'], 'Windows_NT'))
 
     - bash: echo '##vso[task.prependpath]$(System.DefaultWorkingDirectory)/bin'
       displayName: 'Add build binaries to PATH'

doc/contributing.rst

@@ -508,9 +508,10 @@ Continuous Integration (CI)
 
 1. Continuous Integration is by default run on every push in a PR; this clogs
    the CI pipeline and affects other PR's; if you don't need it (e.g. for WIP or
-   documentation only changes), add `[ci skip]` to your commit message title.
-   This convention is supported by `Appveyor
-   <https://www.appveyor.com/docs/how-to/filtering-commits/#skip-directive-in-commit-message>`_
+   documentation only changes), add `[skip ci]` to your commit message title.
+   This convention is supported by our github actions pipelines and our azure pipeline
+   as well as our former other pipelines:
+   `Appveyor <https://www.appveyor.com/docs/how-to/filtering-commits/#skip-directive-in-commit-message>`_
    and `Travis <https://docs.travis-ci.com/user/customizing-the-build/#skipping-a-build>`_.
 
 2. Consider enabling CI (azure, GitHub actions and builds.sr.ht) in your own Nim fork, and