Check for possible broken documentation by failing on DocFX warning

build-system/pr-validation.yaml

@@ -124,6 +124,16 @@ jobs:
       outputDirectory: "TestResults"
       artifactName: "net_core_tests_linux-$(Build.BuildId)"
 
+  - template: azure-pipeline.template.yaml
+    parameters:
+      name: "docfx_test"
+      displayName: "DocFX warning check"
+      vmImage: "windows-2019"
+      scriptFileName: build.cmd
+      scriptArgs: docfx
+      outputDirectory: "TestResults"
+      artifactName: "docfx_test-$(Build.BuildId)"
+
   - template: azure-pipeline.template.yaml
     parameters:
       name: "net_5_tests_windows"

build.fsx

@@ -632,12 +632,19 @@ Target "DocFx" (fun _ ->
                 Version = "0.1.0-alpha-1611021200"
                 OutputDirectory = currentDirectory @@ "tools" }) "msdn.4.5.2"
 
-    let docsPath = "./docs"
-    DocFx (fun p ->
-                { p with
-                    Timeout = TimeSpan.FromMinutes 30.0;
-                    WorkingDirectory  = docsPath;
-                    DocFxJson = docsPath @@ "docfx.json" })
+    let docsPath = FullName "./docs"
+    let docFxPath = FullName(findToolInSubPath "docfx.exe" "tools/docfx.console/tools")
+
+    let args = StringBuilder()
+                |> append (docsPath @@ "docfx.json" )
+                |> append ("--warningsAsErrors")
+                |> toText
+
+    let result = ExecProcess(fun info ->
+            info.FileName <- docFxPath
+            info.WorkingDirectory <- (Path.GetDirectoryName (FullName docFxPath))
+            info.Arguments <- args) (System.TimeSpan.FromMinutes 45.0) (* Reasonably long-running task. *)
+    if result <> 0 then failwithf "DocFX failed. %s %s" docFxPath args
 )
 
 FinalTarget "KillCreatedProcesses" (fun _ ->