[devops] Rework how we hide GitHub comments.

* Whenever we add a GitHub comment, also provide a comment id.
* When adding a GitHub comment, use that comment id to hide any previous
  comments with the same id.

It turns out this simplifies the code a lot, and additionally we now correctly
hide every comment we report whenever a step or stage is re-executed.

tools/devops/automation/scripts/GitHub.psm1

@@ -294,7 +294,8 @@ class GitHubComments {
     }
 
     [void] WriteCommentFooter(
-        [object] $stringBuilder
+        [object] $stringBuilder,
+        [string] $commentId
     ) {
         $targetUrl = Get-TargetUrl
         $stringBuilder.AppendLine("[Pipeline]($targetUrl) on Agent $Env:TESTS_BOT") # Env:TESTS_BOT is added by the pipeline as a variable coming from the execute tests job
@@ -308,12 +309,17 @@ class GitHubComments {
             $hashUrl= "https://github.com/$($this.Org)/$($this.Repo)/commit/$($this.Hash)"
             $hashSource = " [CI build]"
         }
-        $ciComment = "[comment]: <> (This is a comment added by Azure DevOps)"
+        $ciComment = $this.GetCommentIdentifier($commentId)
         $stringBuilder.AppendLine("Hash: [$($this.Hash)]($hashUrl) $hashSource")
         $stringBuilder.AppendLine("")
         $stringBuilder.AppendLine($ciComment)
     }
 
+    [string] GetCommentIdentifier([string] $commentId)
+    {
+        return "[comment]: <> (This is a comment added by Azure DevOps, id: $commentId)"
+    }
+
     [string] GetCommentUrl() {
         # if the build was due to PR, we want to write the comment in the PR rather than in the commit 
         if ([GitHubComments]::IsPR()) {
@@ -360,11 +366,46 @@ class GitHubComments {
         return $request
     }
 
+    [void] HideComments(
+        [string] $commentId
+    ) {
+        if (!$commentId) {
+            Write-Host "Not hiding comments, because no comment id provided"
+            return
+        }
+
+        if (![GitHubComments]::IsPR()) {
+            Write-Host "Not hiding comments, because we're not in a pull request"
+            return
+        }
+
+        $prId = "$Env:BUILD_SOURCEBRANCH".Replace("refs/pull/", "").Replace("/merge", "")
+        $prComments = $this.GetCommentsForPR($prId)
+
+        $botComments = [System.Collections.ArrayList]@()
+        $commentToHide = $this.GetCommentIdentifier($commentId)
+
+        foreach ($c in $prComments) {
+          if ($c.Author -eq "vs-mobiletools-engineering-service2") {
+            if ($c.Body.Contains($CommentToHide)) {
+              $botComments.Add($c)
+            }
+          }
+        }
+
+        Write-Host "Hiding $($botComments.Count) comments for PR #$prId with comment id '$commentId'"
+
+        $this.MinimizeComments($botComments)
+    }
+
     [object] NewCommentFromObject(
         [string] $commentTitle,
         [string] $commentEmoji,
-        [object] $commentObject
+        [object] $commentObject,
+        [string] $commentId
     ) {
+        $this.HideComments($commentId)
+
         # build the message, which will be sent to github, users can use markdown
         $msg = [System.Text.StringBuilder]::new()
 
@@ -376,16 +417,19 @@ class GitHubComments {
         $msg.AppendLine()
 
         # footer
-        $this.WriteCommentFooter($msg)
+        $this.WriteCommentFooter($msg, $commentId)
 
         return $this.NewComment($msg)
     }
 
     [object] NewCommentFromFile(
         [string] $commentTitle,
         [string] $commentEmoji,
-        [string] $filePath
+        [string] $filePath,
+        [string] $commentId
     ) {
+        $this.HideComments($commentId)
+
         # build the message, which will be sent to github, users can use markdown
         $msg = [System.Text.StringBuilder]::new()
 
@@ -404,16 +448,19 @@ class GitHubComments {
         $msg.AppendLine()
 
         # footer
-        $this.WriteCommentFooter($msg)
+        $this.WriteCommentFooter($msg, $commentId)
 
         return $this.NewComment($msg)
     }
 
     [object] NewCommentFromMessage(
         [string] $commentTitle,
         [string] $commentEmoji,
-        [string] $content
+        [string] $content,
+        [string] $commentId
     ) {
+        $this.HideComments($commentId)
+
         $msg = [System.Text.StringBuilder]::new()
 
         # header
@@ -424,7 +471,7 @@ class GitHubComments {
         $msg.AppendLine()
 
         # footer
-        $this.WriteCommentFooter($msg)
+        $this.WriteCommentFooter($msg, $commentId)
 
         return $this.NewComment($msg)
     }

tools/devops/automation/templates/api-diff-stage.yml

@@ -33,18 +33,6 @@ parameters:
 
 stages:
 
-- ${{ if parameters.isPR }}:
-  - stage: clean
-    displayName: 'Clean up'
-    dependsOn: []
-    jobs:
-    - job:
-      displayName: 'Clean comments'
-      pool:
-        vmImage: windows-latest
-      steps:
-      - template: ./common/clean.yml
-
 - stage: configure_build
   displayName: 'Configure'
   jobs:

tools/devops/automation/templates/build/api-diff-process-results.yml

@@ -84,7 +84,7 @@ steps:
         $converted = $inputContents + "`n`nUnable to convert markdown: $_`n`n"
       }
       $githubComments = New-GitHubCommentsObjectFromUrl -Url "$(Build.Repository.Uri)" -Token $Env:GITHUB_TOKEN -Hash $Env:COMMENT_HASH
-      $result = $githubComments.NewCommentFromMessage("", "", $converted)
+      $result = $githubComments.NewCommentFromMessage("", "", $converted, "api diff")
     displayName: 'Publish GitHub comment for change detection'
     timeoutInMinutes: 10
     continueOnError: true  # don't let any failures here stop us

tools/devops/automation/templates/build/build.yml

@@ -205,7 +205,7 @@ steps:
   - pwsh: |
       Import-Module $Env:SYSTEM_DEFAULTWORKINGDIRECTORY\xamarin-macios\tools\devops\automation\scripts\MaciosCI.psd1
       $githubComments = New-GitHubCommentsObjectFromUrl -Url "$(Build.Repository.Uri)" -Token $(GitHub.Token) -Hash $Env:COMMENT_HASH
-      $githubComments.NewCommentFromMessage("Build failed", ":fire:", "Build failed for the job '$(System.JobDisplayName)'")
+      $githubComments.NewCommentFromMessage("Build failed", ":fire:", "Build failed for the job '$(System.JobDisplayName)'", "build")
     condition: failed()
     displayName: 'Report build failure'
     env:

tools/devops/automation/templates/mac/build.yml

@@ -213,10 +213,10 @@ steps:
     $githubComments = New-GitHubCommentsObjectFromUrl -Url "$(Build.Repository.Uri)" -Token $(GitHub.Token) -Hash $Env:COMMENT_HASH
 
     if (Test-Path -Path "$Env:GITHUB_FAILURE_COMMENT_FILE" -PathType Leaf)  {
-      $githubComments.NewCommentFromFile("Tests on macOS ${{ parameters.statusContext }} failed", ":x:", "$Env:GITHUB_FAILURE_COMMENT_FILE")
+      $githubComments.NewCommentFromFile("Tests on macOS ${{ parameters.statusContext }} failed", ":x:", "$Env:GITHUB_FAILURE_COMMENT_FILE", "macOS ${{ parameters.statusContext }}")
     } else {
       $message = ":white_check_mark: **All** tests on macOS ${{ parameters.statusContext }} passed."
-      $githubComments.NewCommentFromMessage("Tests on macOS ${{ parameters.statusContext }} passed", ":computer:", $message)
+      $githubComments.NewCommentFromMessage("Tests on macOS ${{ parameters.statusContext }} passed", ":computer:", $message, "macOS ${{ parameters.statusContext }}")
     }
   displayName: 'Report results to GitHub'
   timeoutInMinutes: 5

tools/devops/automation/templates/main-stage.yml

@@ -202,21 +202,6 @@ stages:
           commit: ${{ parameters.commit }}
           stageDisplayNamePrefix: ${{ parameters.stageDisplayNamePrefix }}
 
-  - ${{ if parameters.isPR }}:
-      - stage: clean
-        displayName: '${{ parameters.stageDisplayNamePrefix }}Clean up'
-        dependsOn: []
-        jobs:
-          - job:
-            displayName: 'Clean comments'
-            pool:
-              name: AzurePipelines-EO
-              demands:
-                - ImageOverride -equals 1ESPT-Windows2022
-
-            steps:
-              - template: ./common/clean.yml
-
   - stage: configure_build
     displayName: '${{ parameters.stageDisplayNamePrefix }}Configure'
     dependsOn: ${{ parameters.dependsOn }}

tools/devops/automation/templates/sign-and-notarized/artifact-github-comment.yml

@@ -29,7 +29,7 @@ steps:
     Import-Module $Env:SYSTEM_DEFAULTWORKINGDIRECTORY\xamarin-macios\tools\devops\automation\scripts\MaciosCI.psd1
     $artifact = New-ArtifactsFromJsonFile -Path "$Env:ARTIFACTS_JSON_PATH"
     $gihubComments = New-GitHubCommentsObjectFromUrl -Url "$(Build.Repository.Uri)" -Token $Env:GITHUB_TOKEN -Hash $Env:COMMENT_HASH
-    $result = $gihubComments.NewCommentFromObject("Artifacts", ":books:", $artifact)
+    $result = $gihubComments.NewCommentFromObject("Artifacts", ":books:", $artifact, "artifacts")
     Write-Host $result
   env:
     GITHUB_TOKEN: $(GitHub.Token)

tools/devops/automation/templates/tests-stage.yml

@@ -163,18 +163,6 @@ parameters:
 
 stages:
 
-- ${{ if parameters.isPR }}:
-  - stage: clean
-    displayName: '${{ parameters.stageDisplayNamePrefix }}Clean up'
-    dependsOn: []
-    jobs:
-    - job:
-      displayName: 'Clean comments'
-      pool:
-        vmImage: windows-latest
-      steps:
-      - template: ./common/clean.yml
-
 - stage: configure_build
   displayName: '${{ parameters.stageDisplayNamePrefix }}Configure'
   dependsOn: ${{ parameters.dependsOn }}

tools/devops/automation/templates/tests/publish-html.yml

@@ -49,12 +49,6 @@ steps:
 
 - template: download-artifacts.yml
 
-- ${{ if parameters.isPR }}:
-  - template: ../common/clean.yml
-    parameters:
-      commentToHide: '[comment]: <> (This is a test result report added by Azure DevOps)'
-      checkoutCode: false # we already execute the 'clean.yml' template elsewhere in this job, and running 'checkout' again is useless (it also leads to duplicate step names which Azure DevOps doesn't like).
-
 - pwsh: $(System.DefaultWorkingDirectory)/xamarin-macios/tools/devops/automation/scripts/show_env.ps1
   displayName: 'Show Environment'
 
@@ -83,7 +77,7 @@ steps:
         }
 
         $gihubComments = New-GitHubCommentsObjectFromUrl -Url "$(Build.Repository.Uri)" -Token $Env:GITHUB_TOKEN -Hash $Env:COMMENT_HASH -Debug
-        $result = $gihubComments.NewCommentFromObject("Test results", $emoji, $parallelResults)
+        $result = $gihubComments.NewCommentFromObject("Test results", $emoji, $parallelResults, "test results")
       } catch {
         Write-Host "##vso[task.complete result=Failed;]Failed to compute test summaries: $_"
         New-GitHubComment -Header "Failed to compute test summaries on $Env:CONTEXT" -Emoji ":fire:" -Description "Failed to compute test summaries: $_."

tools/devops/automation/templates/tests/publish-results.yml

@@ -119,7 +119,7 @@ stages:
         $githubComments = New-GitHubCommentsObjectFromUrl -Url "$(Build.Repository.Uri)" -Token $Env:GITHUB_TOKEN -Hash $Env:COMMENT_HASH -Debug
         $sb = [System.Text.StringBuilder]::new()
         $sb.AppendLine("All tests have been skipped because the label 'skip-all-tests' was set.")
-        $result = $githubComments.NewCommentFromMessage("Test results", ":seedling:", $sb.ToString())
+        $result = $githubComments.NewCommentFromMessage("Test results", ":seedling:", $sb.ToString(), "test results")
       displayName: 'Set comment'
       env:
         CONTEXT: ${{ parameters.statusContext }}

tools/devops/automation/templates/windows/build.yml

@@ -342,13 +342,13 @@ steps:
     $githubComments = New-GitHubCommentsObjectFromUrl -Url "$(Build.Repository.Uri)" -Token $(GitHub.Token) -Hash $Env:COMMENT_HASH
 
     if (Test-Path -Path "$Env:GITHUB_FAILURE_COMMENT_FILE" -PathType Leaf)  {
-      $githubComments.NewCommentFromFile("${{ parameters.statusContext }} failed", ":x:", "$Env:GITHUB_FAILURE_COMMENT_FILE")
+      $githubComments.NewCommentFromFile("${{ parameters.statusContext }} failed", ":x:", "$Env:GITHUB_FAILURE_COMMENT_FILE", "windows tests")
     } elseif ("$($Env:AGENT_JOBSTATUS)" -ne "Succeeded") {
       $message = ":x: $($Env:AGENT_JOBSTATUS) :x:"
-      $githubComments.NewCommentFromMessage("${{ parameters.statusContext }} failed", ":x:", $message)
+      $githubComments.NewCommentFromMessage("${{ parameters.statusContext }} failed", ":x:", $message, "windows tests")
     } else {
       $message = ":white_check_mark: **All** ${{ parameters.statusContext }} passed."
-      $githubComments.NewCommentFromMessage("${{ parameters.statusContext }} passed", ":computer:", $message)
+      $githubComments.NewCommentFromMessage("${{ parameters.statusContext }} passed", ":computer:", $message, "windows tests")
     }
   displayName: 'Report results to GitHub'
   timeoutInMinutes: 5