fix(inbound-api): resolve InboundAPI-009,010,011,013 — cache failed compiles, reject unknown body fields, close enumeration oracle, drop misnamed factory; InboundAPI-007,012 flagged

tests/ScadaLink.InboundAPI.Tests/InboundScriptExecutorTests.cs

@@ -1,3 +1,4 @@
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
 using NSubstitute;
 using ScadaLink.Commons.Entities.InboundApi;
@@ -323,4 +324,63 @@ public class InboundScriptExecutorTests
         Assert.False(result.Success);
         Assert.Contains("timed out", result.ErrorMessage);
     }
+
+    // --- InboundAPI-009: a script that fails to compile must be compiled at most
+    // once — repeated calls must not re-run the expensive Roslyn compilation. ---
+
+    [Fact]
+    public async Task FailedCompilation_IsNotRetriedOnEveryRequest()
+    {
+        // A broken script compiled once must be remembered as bad: subsequent
+        // ExecuteAsync calls must NOT recompile (CPU amplification vector — there is
+        // no rate limiting on the inbound API). Compilation is observed via the
+        // "compilation failed" log line, which must appear exactly once.
+        var counter = new CompileLogCounter();
+        var executor = new InboundScriptExecutor(
+            new CountingLogger<InboundScriptExecutor>(counter),
+            Substitute.For<IServiceProvider>());
+
+        var method = new ApiMethod("broken", "%%% invalid C# %%%") { Id = 1, TimeoutSeconds = 10 };
+
+        for (var i = 0; i < 5; i++)
+        {
+            var result = await executor.ExecuteAsync(
+                method, new Dictionary<string, object?>(), _route, TimeSpan.FromSeconds(10));
+            Assert.False(result.Success);
+        }
+
+        Assert.Equal(1, counter.CompilationFailures);
+    }
+
+    [Fact]
+    public void FailedCompilation_RecompilesAfterCompileAndRegisterCalledAgain()
+    {
+        // The failure cache must not be permanent: when the method definition is
+        // updated via CompileAndRegister, a now-valid script must register.
+        var bad = new ApiMethod("fixable", "%%% invalid %%%") { Id = 1, TimeoutSeconds = 10 };
+        Assert.False(_executor.CompileAndRegister(bad));
+
+        var good = new ApiMethod("fixable", "return 1;") { Id = 1, TimeoutSeconds = 10 };
+        Assert.True(_executor.CompileAndRegister(good));
+    }
+
+    private sealed class CompileLogCounter
+    {
+        public int CompilationFailures;
+    }
+
+    private sealed class CountingLogger<T>(CompileLogCounter counter) : ILogger<T>
+    {
+        public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
+        public bool IsEnabled(LogLevel logLevel) => true;
+
+        public void Log<TState>(
+            LogLevel logLevel, EventId eventId, TState state, Exception? exception,
+            Func<TState, Exception?, string> formatter)
+        {
+            var message = formatter(state, exception);
+            if (message.Contains("script compilation failed", StringComparison.OrdinalIgnoreCase))
+                Interlocked.Increment(ref counter.CompilationFailures);
+        }
+    }
 }