fix(scriptanalysis): warn on scripts blocking on a Task (.Result/.Wait()/GetAwaiter().GetResult()) (review 2026-10-21 01/SR-U2)

Advisory, not a trust-policy violation: every policy entry blocks deploy, and an error here would fail the next redeploy of already-deployed scripts. ValidationService surfaces it as a non-blocking ScriptCompilation warning.
2026-10-22 06:22:01 -04:00
parent 2ca60f86ff
commit 5919a71b8b
8 changed files with 270 additions and 17 deletions
@@ -0,0 +1,50 @@
+using ZB.MOM.WW.ScadaBridge.ScriptAnalysis;
+
+namespace ZB.MOM.WW.ScadaBridge.ScriptAnalysis.Tests;
+
+/// <summary>
+/// Review 2026-10-21 01/SR-U2: synchronously blocking on a Task inside a site
+/// script (<c>.Result</c>, <c>.Wait()</c>, <c>.GetAwaiter().GetResult()</c>) can
+/// starve the dedicated script-execution pool — the awaited helper's continuation
+/// is queued to the same pool the blocked worker occupies. The analyzer reports an
+/// advisory for each such use, resolved semantically so a non-Task <c>.Result</c>
+/// is not flagged.
+/// </summary>
+public class BlockingWaitAnalyzerTests
+{
+    /// <summary>Verifies that each blocking-wait shape on a Task is reported.</summary>
+    /// <param name="code">A script blocking on a Task.</param>
+    [Theory]
+    [InlineData("var r = Instance.CallScript(\"Calc\").Result;")]
+    [InlineData("var s = Notify.Status(\"id\").Result;")]
+    [InlineData("Instance.CallScript(\"Calc\").Wait();")]
+    [InlineData("var r = Instance.CallScript(\"Calc\").GetAwaiter().GetResult();")]
+    [InlineData("var a = Alarms.CurrentAsync().Result;")]
+    [InlineData("var t = System.Threading.Tasks.Task.Delay(1); t.Wait(100);")]
+    [InlineData("var r = Instance.CallScript(\"Calc\").ConfigureAwait(false).GetAwaiter().GetResult();")]
+    public void Find_ReportsBlockingWaitOnTask(string code)
+    {
+        Assert.NotEmpty(BlockingWaitAnalyzer.Find(code, typeof(ScriptCompileSurface)));
+    }
+
+    /// <summary>Verifies that awaited calls and non-Task members named Result/Wait are not reported.</summary>
+    /// <param name="code">A script that does not block on a Task.</param>
+    [Theory]
+    [InlineData("var r = await Instance.CallScript(\"Calc\");")]
+    [InlineData("var a = await Alarms.CurrentAsync();")]
+    [InlineData("var o = new { Result = 1 }; var x = o.Result;")]
+    [InlineData("var t = Instance.CallScript(\"Calc\"); return t.IsCompleted;")]
+    [InlineData("")]
+    public void Find_IgnoresNonBlockingCode(string code)
+    {
+        Assert.Empty(BlockingWaitAnalyzer.Find(code, typeof(ScriptCompileSurface)));
+    }
+
+    /// <summary>Verifies that the advisory names the blocking member so the author can find it.</summary>
+    [Fact]
+    public void Find_MessageNamesTheMember()
+    {
+        var advisories = BlockingWaitAnalyzer.Find("var r = Instance.CallScript(\"Calc\").Result;", typeof(ScriptCompileSurface));
+        Assert.Contains(advisories, a => a.Contains(".Result") && a.Contains("await"));
+    }
+}
@@ -504,6 +504,44 @@ public class ValidationServiceTests
        Assert.Contains(gated.Errors, e => e.Message.Contains("Ghost"));
    }

+    /// <summary>
+    /// Review 2026-10-21 01/SR-U2: a script that blocks on a Task gets a non-blocking
+    /// warning (it still deploys — existing scripts are not broken), naming the script.
+    /// </summary>
+    [Fact]
+    public void Validate_ScriptBlockingOnTask_ReturnsWarningNotError()
+    {
+        var config = new FlattenedConfiguration
+        {
+            InstanceUniqueName = "Instance1",
+            Scripts = [new ResolvedScript { CanonicalName = "Blocker", Code = "var a = Alarms.CurrentAsync().Result;" }]
+        };
+
+        var result = _sut.Validate(config);
+
+        Assert.True(result.IsValid);
+        Assert.Contains(result.Warnings, w =>
+            w.Category == ValidationCategory.ScriptCompilation
+            && w.EntityName == "Blocker"
+            && w.Message.Contains(".Result"));
+    }
+
+    /// <summary>Verifies that an awaiting script produces no blocking-wait warning.</summary>
+    [Fact]
+    public void Validate_ScriptAwaitingTask_NoBlockingWaitWarning()
+    {
+        var config = new FlattenedConfiguration
+        {
+            InstanceUniqueName = "Instance1",
+            Scripts = [new ResolvedScript { CanonicalName = "Good", Code = "var a = await Alarms.CurrentAsync();" }]
+        };
+
+        var result = _sut.Validate(config);
+
+        Assert.True(result.IsValid);
+        Assert.DoesNotContain(result.Warnings, w => w.EntityName == "Good");
+    }
+
    private static FlattenedConfiguration ConfigWithExpressionTriggerScript(string expression)
    {
        var json = System.Text.Json.JsonSerializer.Serialize(new { expression });