Ex CI: add sparse option to checkout template (#4701)

* Ex CI: add sparse option to checkout template

* replace Pipeline.Workspace with Agent.BuildDirectory for consistency

.azuredevops/templates/steps/build-cmake.yml

@@ -10,10 +10,10 @@ parameters:
   default: ''
 - name: cmakeBuildDir
   type: string
-  default: 'build'
+  default: $(Agent.BuildDirectory)/s/build
 - name: cmakeSourceDir
   type: string
-  default: '..'
+  default: $(Agent.BuildDirectory)/s
 - name: customBuildTarget
   type: string
   default: ''
@@ -46,7 +46,7 @@ steps:
     ${{ if eq(parameters.customInstallPath, true) }}:
       cmakeArgs: -DCMAKE_INSTALL_PREFIX=${{ parameters.installDir }} ${{ parameters.extraBuildFlags }} ${{ parameters.cmakeSourceDir }}
     ${{ else }}:
-      cmakeArgs: ${{ parameters.extraBuildFlags }} ..
+      cmakeArgs: ${{ parameters.extraBuildFlags }} ${{ parameters.cmakeSourceDir }}
 - ${{ if parameters.printDiskSpace }}:
   - script: df -h
     displayName: Disk space before build

.azuredevops/templates/steps/checkout.yml

@@ -4,6 +4,12 @@ parameters:
 - name: checkoutRepo
   type: string
   default: 'self'
+- name: sparseCheckout
+  type: boolean
+  default: false
+- name: sparseCheckoutDir
+  type: string
+  default: ''
 # submodule download behaviour
 # change to 'recursive' for repos with submodules
 - name: submoduleBehaviour
@@ -15,3 +21,12 @@ steps:
     clean: true
     submodules: ${{ parameters.submoduleBehaviour }}
     retryCountOnTaskFailure: 3
+    ${{ if eq(parameters.sparseCheckout, true) }}:
+      sparseCheckoutDirectories: ${{ parameters.sparseCheckoutDir }}
+      path: sparse
+  - ${{ if eq(parameters.sparseCheckout, true) }}:
+    - task: Bash@3
+      displayName: Symlink sparse checkout
+      inputs:
+        targetType: inline
+        script: ln -s $(Agent.BuildDirectory)/sparse/${{ parameters.sparseCheckoutDir }} $(Agent.BuildDirectory)/s