fix PR builds

build/azure-pipelines/darwin/continuous-build-darwin.yml

@@ -2,24 +2,25 @@ steps:
 - task: NodeTool@0
   inputs:
     versionSpec: "10.15.1"
+- task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
+  inputs:
+    versionSpec: "1.10.1"
 - task: 1ESLighthouseEng.PipelineArtifactCaching.RestoreCacheV1.RestoreCache@1
   inputs:
     keyfile: '**/yarn.lock, !**/node_modules/**/yarn.lock, !**/.*/**/yarn.lock'
     targetfolder: '**/node_modules, !**/node_modules/**/node_modules'
     vstsFeed: '$(ArtifactFeed)'
-- task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
-  inputs:
-    versionSpec: "1.10.1"
+  condition: eq(variables['System.PullRequest.PullRequestId'], '')
 - script: |
     yarn
   displayName: Install Dependencies
-  condition: ne(variables['CacheRestored'], 'true')
+  condition: or(ne(variables['System.PullRequest.PullRequestId'], ''), ne(variables['CacheRestored'], 'true'))
 - task: 1ESLighthouseEng.PipelineArtifactCaching.SaveCacheV1.SaveCache@1
   inputs:
     keyfile: '**/yarn.lock, !**/node_modules/**/yarn.lock, !**/.*/**/yarn.lock'
     targetfolder: '**/node_modules, !**/node_modules/**/node_modules'
     vstsFeed: '$(ArtifactFeed)'
-  condition: and(succeeded(), ne(variables['CacheRestored'], 'true'))
+  condition: and(succeeded(), eq(variables['System.PullRequest.PullRequestId'], ''), ne(variables['CacheRestored'], 'true'))
 - script: |
     yarn gulp electron-x64
   displayName: Download Electron

build/azure-pipelines/linux/continuous-build-linux.yml

@@ -10,24 +10,25 @@ steps:
 - task: NodeTool@0
   inputs:
     versionSpec: "10.15.1"
+- task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
+  inputs:
+    versionSpec: "1.10.1"
 - task: 1ESLighthouseEng.PipelineArtifactCaching.RestoreCacheV1.RestoreCache@1
   inputs:
     keyfile: '**/yarn.lock, !**/node_modules/**/yarn.lock, !**/.*/**/yarn.lock'
     targetfolder: '**/node_modules, !**/node_modules/**/node_modules'
     vstsFeed: '$(ArtifactFeed)'
-- task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
-  inputs:
-    versionSpec: "1.10.1"
+  condition: eq(variables['System.PullRequest.PullRequestId'], '')
 - script: |
     yarn
   displayName: Install Dependencies
-  condition: ne(variables['CacheRestored'], 'true')
+  condition: or(ne(variables['System.PullRequest.PullRequestId'], ''), ne(variables['CacheRestored'], 'true'))
 - task: 1ESLighthouseEng.PipelineArtifactCaching.SaveCacheV1.SaveCache@1
   inputs:
     keyfile: '**/yarn.lock, !**/node_modules/**/yarn.lock, !**/.*/**/yarn.lock'
     targetfolder: '**/node_modules, !**/node_modules/**/node_modules'
     vstsFeed: '$(ArtifactFeed)'
-  condition: and(succeeded(), ne(variables['CacheRestored'], 'true'))
+  condition: and(succeeded(), eq(variables['System.PullRequest.PullRequestId'], ''), ne(variables['CacheRestored'], 'true'))
 - script: |
     yarn gulp electron-x64
   displayName: Download Electron

build/azure-pipelines/win32/continuous-build-win32.yml

@@ -14,16 +14,17 @@ steps:
     keyfile: '**/yarn.lock, !**/node_modules/**/yarn.lock, !**/.*/**/yarn.lock'
     targetfolder: '**/node_modules, !**/node_modules/**/node_modules'
     vstsFeed: '$(ArtifactFeed)'
+  condition: eq(variables['System.PullRequest.PullRequestId'], '')
 - powershell: |
     yarn
   displayName: Install Dependencies
-  condition: ne(variables['CacheRestored'], 'true')
+  condition: or(ne(variables['System.PullRequest.PullRequestId'], ''), ne(variables['CacheRestored'], 'true'))
 - task: 1ESLighthouseEng.PipelineArtifactCaching.SaveCacheV1.SaveCache@1
   inputs:
     keyfile: '**/yarn.lock, !**/node_modules/**/yarn.lock, !**/.*/**/yarn.lock'
     targetfolder: '**/node_modules, !**/node_modules/**/node_modules'
     vstsFeed: '$(ArtifactFeed)'
-  condition: and(succeeded(), ne(variables['CacheRestored'], 'true'))
+  condition: and(succeeded(), eq(variables['System.PullRequest.PullRequestId'], ''), ne(variables['CacheRestored'], 'true'))
 - powershell: |
     yarn gulp electron
   displayName: Download Electron