Implement deferred core utility parity APIs/tests and refresh tracking artifacts

dotnet/src/ZB.MOM.NatsNet.Server/Internal/AccessTimeService.cs

@@ -25,6 +25,18 @@ public static class AccessTimeService
         // Mirror Go's init(): nothing to pre-allocate in .NET.
     }
 
+    /// <summary>
+    /// Explicit init hook for Go parity.
+    /// Mirrors package <c>init()</c> in server/ats/ats.go.
+    /// This method is intentionally idempotent.
+    /// </summary>
+    public static void Init()
+    {
+        // Ensure a non-zero cached timestamp is present.
+        var now = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds() * 1_000_000L;
+        Interlocked.CompareExchange(ref _utime, now, 0);
+    }
+
     /// <summary>
     /// Registers a user. Starts the background timer when the first registrant calls this.
     /// Each call to <see cref="Register"/> must be paired with a call to <see cref="Unregister"/>.

dotnet/src/ZB.MOM.NatsNet.Server/Internal/IpQueue.cs

@@ -40,6 +40,24 @@ public sealed class IpQueue<T>
     /// <summary>Default maximum size of the recycled backing-list capacity.</summary>
     public const int DefaultMaxRecycleSize = 4 * 1024;
 
+    /// <summary>
+    /// Functional option type used by <see cref="NewIPQueue"/>.
+    /// Mirrors Go <c>ipQueueOpt</c>.
+    /// </summary>
+    public delegate void IpQueueOption(IpQueueOptions options);
+
+    /// <summary>
+    /// Option bag used by <see cref="NewIPQueue"/>.
+    /// Mirrors Go <c>ipQueueOpts</c>.
+    /// </summary>
+    public sealed class IpQueueOptions
+    {
+        public int MaxRecycleSize { get; set; } = DefaultMaxRecycleSize;
+        public Func<T, ulong>? SizeCalc { get; set; }
+        public ulong MaxSize { get; set; }
+        public int MaxLen { get; set; }
+    }
+
     private long _inprogress;
     private readonly object _lock = new();
 
@@ -68,6 +86,56 @@ public sealed class IpQueue<T>
     /// <summary>Notification channel reader — wait on this to learn items were added.</summary>
     public ChannelReader<bool> Ch => _ch.Reader;
 
+    /// <summary>
+    /// Option helper that configures maximum recycled backing-list size.
+    /// Mirrors Go <c>ipqMaxRecycleSize</c>.
+    /// </summary>
+    public static IpQueueOption IpqMaxRecycleSize(int max) =>
+        options => options.MaxRecycleSize = max;
+
+    /// <summary>
+    /// Option helper that enables size accounting for queue elements.
+    /// Mirrors Go <c>ipqSizeCalculation</c>.
+    /// </summary>
+    public static IpQueueOption IpqSizeCalculation(Func<T, ulong> calc) =>
+        options => options.SizeCalc = calc;
+
+    /// <summary>
+    /// Option helper that limits queue pushes by total accounted size.
+    /// Mirrors Go <c>ipqLimitBySize</c>.
+    /// </summary>
+    public static IpQueueOption IpqLimitBySize(ulong max) =>
+        options => options.MaxSize = max;
+
+    /// <summary>
+    /// Option helper that limits queue pushes by element count.
+    /// Mirrors Go <c>ipqLimitByLen</c>.
+    /// </summary>
+    public static IpQueueOption IpqLimitByLen(int max) =>
+        options => options.MaxLen = max;
+
+    /// <summary>
+    /// Factory wrapper for Go parity.
+    /// Mirrors <c>newIPQueue</c>.
+    /// </summary>
+    public static IpQueue<T> NewIPQueue(
+        string name,
+        ConcurrentDictionary<string, object>? registry = null,
+        params IpQueueOption[] options)
+    {
+        var opts = new IpQueueOptions();
+        foreach (var option in options)
+            option(opts);
+
+        return new IpQueue<T>(
+            name,
+            registry,
+            opts.MaxRecycleSize,
+            opts.SizeCalc,
+            opts.MaxSize,
+            opts.MaxLen);
+    }
+
     /// <summary>
     /// Creates a new queue, optionally registering it in <paramref name="registry"/>.
     /// Mirrors <c>newIPQueue</c>.

dotnet/src/ZB.MOM.NatsNet.Server/Internal/RateCounter.cs

@@ -38,6 +38,12 @@ public sealed class RateCounter
         Interval = TimeSpan.FromSeconds(1);
     }
 
+    /// <summary>
+    /// Factory wrapper for Go parity.
+    /// Mirrors <c>newRateCounter</c>.
+    /// </summary>
+    public static RateCounter NewRateCounter(long limit) => new(limit);
+
     /// <summary>
     /// Returns true if the event is within the rate limit for the current window.
     /// Mirrors <c>rateCounter.allow</c>.

dotnet/src/ZB.MOM.NatsNet.Server/Internal/ServerUtilities.cs

@@ -14,6 +14,8 @@
 // Adapted from server/util.go in the NATS server Go source.
 
 using System.Net;
+using System.Text;
+using System.Text.Json;
 using System.Text.RegularExpressions;
 
 namespace ZB.MOM.NatsNet.Server.Internal;
@@ -268,6 +270,25 @@ public static class ServerUtilities
         return client;
     }
 
+    /// <summary>
+    /// Parity wrapper for Go <c>natsDialTimeout</c>.
+    /// Accepts a network label (tcp/tcp4/tcp6) and host:port address.
+    /// </summary>
+    public static Task<System.Net.Sockets.TcpClient> NatsDialTimeout(
+        string network, string address, TimeSpan timeout)
+    {
+        if (!string.Equals(network, "tcp", StringComparison.OrdinalIgnoreCase) &&
+            !string.Equals(network, "tcp4", StringComparison.OrdinalIgnoreCase) &&
+            !string.Equals(network, "tcp6", StringComparison.OrdinalIgnoreCase))
+            throw new NotSupportedException($"unsupported network: {network}");
+
+        var (host, port, err) = ParseHostPort(address, defaultPort: 0);
+        if (err != null || port <= 0)
+            throw new InvalidOperationException($"invalid dial address: {address}", err);
+
+        return NatsDialTimeoutAsync(host, port, timeout);
+    }
+
     // -------------------------------------------------------------------------
     // URL redaction
     // -------------------------------------------------------------------------
@@ -337,6 +358,54 @@ public static class ServerUtilities
         return result;
     }
 
+    // -------------------------------------------------------------------------
+    // RefCountedUrlSet wrappers (Go parity mapping)
+    // -------------------------------------------------------------------------
+
+    /// <summary>
+    /// Parity wrapper for <see cref="RefCountedUrlSet.AddUrl"/>.
+    /// Mirrors <c>refCountedUrlSet.addUrl</c>.
+    /// </summary>
+    public static bool AddUrl(RefCountedUrlSet urlSet, string urlStr)
+    {
+        ArgumentNullException.ThrowIfNull(urlSet);
+        return urlSet.AddUrl(urlStr);
+    }
+
+    /// <summary>
+    /// Parity wrapper for <see cref="RefCountedUrlSet.RemoveUrl"/>.
+    /// Mirrors <c>refCountedUrlSet.removeUrl</c>.
+    /// </summary>
+    public static bool RemoveUrl(RefCountedUrlSet urlSet, string urlStr)
+    {
+        ArgumentNullException.ThrowIfNull(urlSet);
+        return urlSet.RemoveUrl(urlStr);
+    }
+
+    /// <summary>
+    /// Parity wrapper for <see cref="RefCountedUrlSet.GetAsStringSlice"/>.
+    /// Mirrors <c>refCountedUrlSet.getAsStringSlice</c>.
+    /// </summary>
+    public static string[] GetAsStringSlice(RefCountedUrlSet urlSet)
+    {
+        ArgumentNullException.ThrowIfNull(urlSet);
+        return urlSet.GetAsStringSlice();
+    }
+
+    // -------------------------------------------------------------------------
+    // INFO helpers
+    // -------------------------------------------------------------------------
+
+    /// <summary>
+    /// Serialises <paramref name="info"/> into an INFO line (<c>INFO {...}\r\n</c>).
+    /// Mirrors <c>generateInfoJSON</c>.
+    /// </summary>
+    public static byte[] GenerateInfoJSON(global::ZB.MOM.NatsNet.Server.ServerInfo info)
+    {
+        var json = JsonSerializer.Serialize(info);
+        return Encoding.UTF8.GetBytes($"INFO {json}\r\n");
+    }
+
     // -------------------------------------------------------------------------
     // Copy helpers
     // -------------------------------------------------------------------------
@@ -391,6 +460,13 @@ public static class ServerUtilities
 
         return channel.Writer;
     }
+
+    /// <summary>
+    /// Parity wrapper for <see cref="CreateParallelTaskQueue"/>.
+    /// Mirrors <c>parallelTaskQueue</c>.
+    /// </summary>
+    public static System.Threading.Channels.ChannelWriter<Action> ParallelTaskQueue(int maxParallelism = 0) =>
+        CreateParallelTaskQueue(maxParallelism);
 }
 
 // -------------------------------------------------------------------------

dotnet/src/ZB.MOM.NatsNet.Server/Internal/SignalHandler.cs

@@ -187,6 +187,12 @@ public static class SignalHandler
         _ => throw new ArgumentOutOfRangeException(nameof(command), $"unknown signal \"{CommandToString(command)}\""),
     };
 
+    /// <summary>
+    /// Go parity alias for <see cref="CommandToUnixSignal"/>.
+    /// Mirrors <c>CommandToSignal</c> in signal.go.
+    /// </summary>
+    public static UnixSignal CommandToSignal(ServerCommand command) => CommandToUnixSignal(command);
+
     private static Exception? SendSignal(int pid, UnixSignal signal)
     {
         try

dotnet/tests/ZB.MOM.NatsNet.Server.Tests/Internal/AccessTimeServiceTests.cs

@@ -77,4 +77,16 @@ public sealed class AccessTimeServiceTests : IDisposable
         // Mirror: TestUnbalancedUnregister
         Should.Throw<InvalidOperationException>(() => AccessTimeService.Unregister());
     }
+
+    [Fact]
+    public void Init_ShouldBeIdempotentAndNonThrowing()
+    {
+        Should.NotThrow(() => AccessTimeService.Init());
+        var first = AccessTimeService.AccessTime();
+        first.ShouldBeGreaterThan(0);
+
+        Should.NotThrow(() => AccessTimeService.Init());
+        var second = AccessTimeService.AccessTime();
+        second.ShouldBeGreaterThan(0);
+    }
 }

dotnet/tests/ZB.MOM.NatsNet.Server.Tests/Internal/IpQueueTests.cs

@@ -28,6 +28,62 @@ namespace ZB.MOM.NatsNet.Server.Tests.Internal;
 /// </summary>
 public sealed class IpQueueTests
 {
+    [Fact]
+    public void IpqMaxRecycleSize_ShouldAffectQueueConfig()
+    {
+        var q = IpQueue<int>.NewIPQueue("opt-max-recycle", null, IpQueue<int>.IpqMaxRecycleSize(123));
+        q.MaxRecycleSize.ShouldBe(123);
+    }
+
+    [Fact]
+    public void IpqSizeCalculation_AndLimitBySize_ShouldEnforceLimit()
+    {
+        var q = IpQueue<byte[]>.NewIPQueue(
+            "opt-size-limit",
+            null,
+            IpQueue<byte[]>.IpqSizeCalculation(e => (ulong)e.Length),
+            IpQueue<byte[]>.IpqLimitBySize(8));
+
+        var (_, err1) = q.Push(new byte[4]);
+        err1.ShouldBeNull();
+
+        var (_, err2) = q.Push(new byte[4]);
+        err2.ShouldBeNull();
+
+        var (_, err3) = q.Push(new byte[1]);
+        err3.ShouldBeSameAs(IpQueueErrors.SizeLimitReached);
+    }
+
+    [Fact]
+    public void IpqLimitByLen_ShouldEnforceLengthLimit()
+    {
+        var q = IpQueue<int>.NewIPQueue("opt-len-limit", null, IpQueue<int>.IpqLimitByLen(2));
+
+        q.Push(1).error.ShouldBeNull();
+        q.Push(2).error.ShouldBeNull();
+        q.Push(3).error.ShouldBeSameAs(IpQueueErrors.LenLimitReached);
+    }
+
+    [Fact]
+    public void NewIPQueue_ShouldApplyOptionsAndRegister()
+    {
+        var registry = new ConcurrentDictionary<string, object>();
+        var q = IpQueue<int>.NewIPQueue(
+            "opt-factory",
+            registry,
+            IpQueue<int>.IpqMaxRecycleSize(55),
+            IpQueue<int>.IpqLimitByLen(1));
+
+        q.MaxRecycleSize.ShouldBe(55);
+        registry.TryGetValue("opt-factory", out var registered).ShouldBeTrue();
+        registered.ShouldBeSameAs(q);
+
+        var (_, err1) = q.Push(1);
+        err1.ShouldBeNull();
+        var (_, err2) = q.Push(2);
+        err2.ShouldBeSameAs(IpQueueErrors.LenLimitReached);
+    }
+
     [Fact]
     public void Basic_ShouldInitialiseCorrectly()
     {

dotnet/tests/ZB.MOM.NatsNet.Server.Tests/Internal/RateCounterTests.cs

@@ -22,6 +22,17 @@ namespace ZB.MOM.NatsNet.Server.Tests.Internal;
 /// </summary>
 public sealed class RateCounterTests
 {
+    [Fact]
+    public void NewRateCounter_ShouldCreateWithDefaultInterval()
+    {
+        var counter = RateCounter.NewRateCounter(2);
+        counter.Interval.ShouldBe(TimeSpan.FromSeconds(1));
+
+        counter.Allow().ShouldBeTrue();
+        counter.Allow().ShouldBeTrue();
+        counter.Allow().ShouldBeFalse();
+    }
+
     [Fact]
     public async Task RateCounter_ShouldAllowUpToLimitThenBlockAndReset()
     {

dotnet/tests/ZB.MOM.NatsNet.Server.Tests/Internal/ServerUtilitiesTests.cs

@@ -11,7 +11,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+using System.Net;
+using System.Text.Json;
 using Shouldly;
+using ZB.MOM.NatsNet.Server;
 using ZB.MOM.NatsNet.Server.Internal;
 
 namespace ZB.MOM.NatsNet.Server.Tests.Internal;
@@ -191,4 +194,86 @@ public sealed class ServerUtilitiesTests
                     $"VersionAtLeast({version}, {major}, {minor}, {update})");
         }
     }
+
+    [Fact]
+    public void RefCountedUrlSet_Wrappers_ShouldTrackRefCounts()
+    {
+        var set = new RefCountedUrlSet();
+        ServerUtilities.AddUrl(set, "nats://a:4222").ShouldBeTrue();
+        ServerUtilities.AddUrl(set, "nats://a:4222").ShouldBeFalse();
+        ServerUtilities.AddUrl(set, "nats://b:4222").ShouldBeTrue();
+
+        ServerUtilities.RemoveUrl(set, "nats://a:4222").ShouldBeFalse();
+        ServerUtilities.RemoveUrl(set, "nats://a:4222").ShouldBeTrue();
+
+        var urls = ServerUtilities.GetAsStringSlice(set);
+        urls.Length.ShouldBe(1);
+        urls[0].ShouldBe("nats://b:4222");
+    }
+
+    [Fact]
+    public async Task NatsDialTimeout_ShouldConnectWithinTimeout()
+    {
+        using var listener = new System.Net.Sockets.TcpListener(IPAddress.Loopback, 0);
+        listener.Start();
+        var port = ((IPEndPoint)listener.LocalEndpoint).Port;
+        var acceptTask = listener.AcceptTcpClientAsync();
+
+        using var client = await ServerUtilities.NatsDialTimeout(
+            "tcp",
+            $"127.0.0.1:{port}",
+            TimeSpan.FromSeconds(2));
+
+        client.Connected.ShouldBeTrue();
+        using var accepted = await acceptTask;
+        accepted.Connected.ShouldBeTrue();
+    }
+
+    [Fact]
+    public void GenerateInfoJSON_ShouldEmitInfoLineWithCRLF()
+    {
+        var info = new ServerInfo
+        {
+            Id = "S1",
+            Name = "n1",
+            Host = "127.0.0.1",
+            Port = 4222,
+            Version = "2.0.0",
+            Proto = 1,
+            GoVersion = "go1.23",
+        };
+
+        var bytes = ServerUtilities.GenerateInfoJSON(info);
+        var line = System.Text.Encoding.UTF8.GetString(bytes);
+        line.ShouldStartWith("INFO ");
+        line.ShouldEndWith("\r\n");
+
+        var json = line["INFO ".Length..^2];
+        var payload = JsonSerializer.Deserialize<ServerInfo>(json);
+        payload.ShouldNotBeNull();
+        payload!.Id.ShouldBe("S1");
+    }
+
+    [Fact]
+    public async Task ParallelTaskQueue_ShouldExecuteQueuedActions()
+    {
+        var writer = ServerUtilities.ParallelTaskQueue(maxParallelism: 2);
+        var ran = 0;
+        var tcs = new TaskCompletionSource(TaskCreationOptions.RunContinuationsAsynchronously);
+
+        for (var i = 0; i < 4; i++)
+        {
+            var accepted = writer.TryWrite(() =>
+            {
+                if (Interlocked.Increment(ref ran) == 4)
+                    tcs.TrySetResult();
+            });
+            accepted.ShouldBeTrue();
+        }
+
+        writer.TryComplete().ShouldBeTrue();
+        var finished = await Task.WhenAny(tcs.Task, Task.Delay(TimeSpan.FromSeconds(2)));
+        finished.ShouldBe(tcs.Task);
+        ran.ShouldBe(4);
+    }
 }

dotnet/tests/ZB.MOM.NatsNet.Server.Tests/Internal/SignalHandlerTests.cs

@@ -35,6 +35,16 @@ public sealed class SignalHandlerTests : IDisposable
         SignalHandler.CommandToUnixSignal(ServerCommand.LameDuckMode).ShouldBe(UnixSignal.SigUsr2);
     }
 
+    [Fact]
+    public void CommandToSignal_ShouldMatchCommandToUnixSignal()
+    {
+        foreach (var command in Enum.GetValues<ServerCommand>())
+        {
+            SignalHandler.CommandToSignal(command)
+                .ShouldBe(SignalHandler.CommandToUnixSignal(command));
+        }
+    }
+
     [Fact] // T:3155
     public void SetProcessName_ShouldNotThrow()
     {

reports/current.md

@@ -1,6 +1,6 @@
 # NATS .NET Porting Status Report
 
-Generated: 2026-02-27 15:04:33 UTC
+Generated: 2026-02-27 15:27:06 UTC
 
 ## Modules (12 total)
 
@@ -12,10 +12,10 @@ Generated: 2026-02-27 15:04:33 UTC
 
 | Status | Count |
 |--------|-------|
-| deferred | 2397 |
+| deferred | 2377 |
-| n_a | 18 |
+| n_a | 24 |
 | stub | 1 |
-| verified | 1257 |
+| verified | 1271 |
 
 ## Unit Tests (3257 total)
 
@@ -34,4 +34,4 @@ Generated: 2026-02-27 15:04:33 UTC
 
 ## Overall Progress
 
-**1884/6942 items complete (27.1%)**
+**1904/6942 items complete (27.4%)**

reports/report_c0aaae9.md

@@ -0,0 +1,37 @@
+# NATS .NET Porting Status Report
+
+Generated: 2026-02-27 15:27:06 UTC
+
+## Modules (12 total)
+
+| Status | Count |
+|--------|-------|
+| verified | 12 |
+
+## Features (3673 total)
+
+| Status | Count |
+|--------|-------|
+| deferred | 2377 |
+| n_a | 24 |
+| stub | 1 |
+| verified | 1271 |
+
+## Unit Tests (3257 total)
+
+| Status | Count |
+|--------|-------|
+| deferred | 2660 |
+| n_a | 187 |
+| verified | 410 |
+
+## Library Mappings (36 total)
+
+| Status | Count |
+|--------|-------|
+| mapped | 36 |
+
+
+## Overall Progress
+
+**1904/6942 items complete (27.4%)**

tools/go-analyzer/analyzer.go

@@ -256,6 +256,10 @@ func (a *Analyzer) parseTestFile(filePath string) ([]TestFunc, []ImportInfo, int
 		}
 
 		test.FeatureName = a.inferFeatureName(name)
+		test.BestFeatureIdx = -1
+		if fn.Body != nil {
+			test.Calls = a.extractCalls(fn.Body)
+		}
 		tests = append(tests, test)
 	}
 
@@ -331,6 +335,210 @@ func (a *Analyzer) inferFeatureName(testName string) string {
 	return name
 }
 
+// extractCalls walks an AST block statement and extracts all function/method calls.
+func (a *Analyzer) extractCalls(body *ast.BlockStmt) []CallInfo {
+	seen := make(map[string]bool)
+	var calls []CallInfo
+
+	ast.Inspect(body, func(n ast.Node) bool {
+		callExpr, ok := n.(*ast.CallExpr)
+		if !ok {
+			return true
+		}
+
+		var ci CallInfo
+		switch fun := callExpr.Fun.(type) {
+		case *ast.Ident:
+			ci = CallInfo{FuncName: fun.Name}
+		case *ast.SelectorExpr:
+			ci = CallInfo{
+				RecvOrPkg:  extractIdent(fun.X),
+				MethodName: fun.Sel.Name,
+				IsSelector: true,
+			}
+		default:
+			return true
+		}
+
+		key := ci.callKey()
+		if !seen[key] && !isFilteredCall(ci) {
+			seen[key] = true
+			calls = append(calls, ci)
+		}
+		return true
+	})
+
+	return calls
+}
+
+// extractIdent extracts an identifier name from an expression (handles X in X.Y).
+func extractIdent(expr ast.Expr) string {
+	switch e := expr.(type) {
+	case *ast.Ident:
+		return e.Name
+	case *ast.SelectorExpr:
+		return extractIdent(e.X) + "." + e.Sel.Name
+	default:
+		return ""
+	}
+}
+
+// isFilteredCall returns true if a call should be excluded from feature matching.
+func isFilteredCall(c CallInfo) bool {
+	if c.IsSelector {
+		recv := c.RecvOrPkg
+		// testing.T/B methods
+		if recv == "t" || recv == "b" || recv == "tb" {
+			return true
+		}
+		// stdlib packages
+		if stdlibPkgs[recv] {
+			return true
+		}
+		// NATS client libs
+		if recv == "nats" || recv == "nuid" || recv == "nkeys" || recv == "jwt" {
+			return true
+		}
+		return false
+	}
+
+	// Go builtins
+	name := c.FuncName
+	if builtinFuncs[name] {
+		return true
+	}
+
+	// Test assertion helpers
+	lower := strings.ToLower(name)
+	if strings.HasPrefix(name, "require_") {
+		return true
+	}
+	for _, prefix := range []string{"check", "verify", "assert", "expect"} {
+		if strings.HasPrefix(lower, prefix) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// featureRef identifies a feature within the analysis result.
+type featureRef struct {
+	moduleIdx  int
+	featureIdx int
+	goFile     string
+	goClass    string
+}
+
+// resolveCallGraph matches test calls against known features across all modules.
+func resolveCallGraph(result *AnalysisResult) {
+	// Build method index: go_method name → list of feature refs
+	methodIndex := make(map[string][]featureRef)
+	for mi, mod := range result.Modules {
+		for fi, feat := range mod.Features {
+			ref := featureRef{
+				moduleIdx:  mi,
+				featureIdx: fi,
+				goFile:     feat.GoFile,
+				goClass:    feat.GoClass,
+			}
+			methodIndex[feat.GoMethod] = append(methodIndex[feat.GoMethod], ref)
+		}
+	}
+
+	// For each test, resolve calls to features
+	for mi := range result.Modules {
+		mod := &result.Modules[mi]
+		for ti := range mod.Tests {
+			test := &mod.Tests[ti]
+			seen := make(map[int]bool) // feature indices already linked
+			var linked []int
+
+			testFileBase := sourceFileBase(test.GoFile)
+
+			for _, call := range test.Calls {
+				// Look up the method name
+				name := call.MethodName
+				if !call.IsSelector {
+					name = call.FuncName
+				}
+
+				candidates := methodIndex[name]
+				if len(candidates) == 0 {
+					continue
+				}
+				// Ambiguity threshold: skip very common method names
+				if len(candidates) > 10 {
+					continue
+				}
+
+				// Filter to same module
+				var sameModule []featureRef
+				for _, ref := range candidates {
+					if ref.moduleIdx == mi {
+						sameModule = append(sameModule, ref)
+					}
+				}
+				if len(sameModule) == 0 {
+					continue
+				}
+
+				for _, ref := range sameModule {
+					if !seen[ref.featureIdx] {
+						seen[ref.featureIdx] = true
+						linked = append(linked, ref.featureIdx)
+					}
+				}
+			}
+
+			test.LinkedFeatures = linked
+
+			// Set BestFeatureIdx using priority:
+			// (a) existing inferFeatureName match
+			// (b) same-file-base match
+			// (c) first remaining candidate
+			if test.BestFeatureIdx < 0 && len(linked) > 0 {
+				// Try same-file-base match first
+				for _, fi := range linked {
+					featFileBase := sourceFileBase(mod.Features[fi].GoFile)
+					if featFileBase == testFileBase {
+						test.BestFeatureIdx = fi
+						break
+					}
+				}
+				// Fall back to first candidate
+				if test.BestFeatureIdx < 0 {
+					test.BestFeatureIdx = linked[0]
+				}
+			}
+		}
+	}
+}
+
+// sourceFileBase strips _test.go suffix and path to get the base file name.
+func sourceFileBase(goFile string) string {
+	base := filepath.Base(goFile)
+	base = strings.TrimSuffix(base, "_test.go")
+	base = strings.TrimSuffix(base, ".go")
+	return base
+}
+
+var stdlibPkgs = map[string]bool{
+	"fmt": true, "time": true, "strings": true, "bytes": true, "errors": true,
+	"os": true, "math": true, "sort": true, "reflect": true, "sync": true,
+	"context": true, "io": true, "filepath": true, "strconv": true,
+	"encoding": true, "json": true, "binary": true, "hex": true, "rand": true,
+	"runtime": true, "atomic": true, "slices": true, "testing": true,
+	"net": true, "bufio": true, "crypto": true, "log": true, "regexp": true,
+	"unicode": true, "http": true, "url": true,
+}
+
+var builtinFuncs = map[string]bool{
+	"make": true, "append": true, "len": true, "cap": true, "close": true,
+	"delete": true, "panic": true, "recover": true, "print": true,
+	"println": true, "copy": true, "new": true,
+}
+
 // isStdlib checks if an import path is a Go standard library package.
 func isStdlib(importPath string) bool {
 	firstSlash := strings.Index(importPath, "/")

tools/go-analyzer/main.go

@@ -11,28 +11,47 @@ func main() {
 	sourceDir := flag.String("source", "", "Path to Go source root (e.g., ../../golang/nats-server)")
 	dbPath := flag.String("db", "", "Path to SQLite database file (e.g., ../../porting.db)")
 	schemaPath := flag.String("schema", "", "Path to SQL schema file (e.g., ../../porting-schema.sql)")
+	mode := flag.String("mode", "full", "Analysis mode: 'full' (default) or 'call-graph' (incremental)")
 	flag.Parse()
 
-	if *sourceDir == "" || *dbPath == "" || *schemaPath == "" {
+	if *sourceDir == "" || *dbPath == "" {
-		fmt.Fprintf(os.Stderr, "Usage: go-analyzer --source <path> --db <path> --schema <path>\n")
+		fmt.Fprintf(os.Stderr, "Usage: go-analyzer --source <path> --db <path> [--schema <path>] [--mode full|call-graph]\n")
 		flag.PrintDefaults()
 		os.Exit(1)
 	}
 
+	switch *mode {
+	case "full":
+		runFull(*sourceDir, *dbPath, *schemaPath)
+	case "call-graph":
+		runCallGraph(*sourceDir, *dbPath)
+	default:
+		log.Fatalf("Unknown mode %q: must be 'full' or 'call-graph'", *mode)
+	}
+}
+
+func runFull(sourceDir, dbPath, schemaPath string) {
+	if schemaPath == "" {
+		log.Fatal("--schema is required for full mode")
+	}
+
 	// Open DB and apply schema
-	db, err := OpenDB(*dbPath, *schemaPath)
+	db, err := OpenDB(dbPath, schemaPath)
 	if err != nil {
 		log.Fatalf("Failed to open database: %v", err)
 	}
 	defer db.Close()
 
 	// Run analysis
-	analyzer := NewAnalyzer(*sourceDir)
+	analyzer := NewAnalyzer(sourceDir)
 	result, err := analyzer.Analyze()
 	if err != nil {
 		log.Fatalf("Analysis failed: %v", err)
 	}
 
+	// Resolve call graph before writing
+	resolveCallGraph(result)
+
 	// Write to DB
 	writer := NewDBWriter(db)
 	if err := writer.WriteAll(result); err != nil {
@@ -46,3 +65,35 @@ func main() {
 	fmt.Printf("  Dependencies:  %d\n", len(result.Dependencies))
 	fmt.Printf("  Imports:       %d\n", len(result.Imports))
 }
+
+func runCallGraph(sourceDir, dbPath string) {
+	// Open existing DB without schema
+	db, err := OpenDBNoSchema(dbPath)
+	if err != nil {
+		log.Fatalf("Failed to open database: %v", err)
+	}
+	defer db.Close()
+
+	// Run analysis (parse Go source)
+	analyzer := NewAnalyzer(sourceDir)
+	result, err := analyzer.Analyze()
+	if err != nil {
+		log.Fatalf("Analysis failed: %v", err)
+	}
+
+	// Resolve call graph
+	resolveCallGraph(result)
+
+	// Update DB incrementally
+	writer := NewDBWriter(db)
+	stats, err := writer.UpdateCallGraph(result)
+	if err != nil {
+		log.Fatalf("Failed to update call graph: %v", err)
+	}
+
+	fmt.Printf("Call graph analysis complete:\n")
+	fmt.Printf("  Tests analyzed:    %d\n", stats.TestsAnalyzed)
+	fmt.Printf("  Tests linked:      %d\n", stats.TestsLinked)
+	fmt.Printf("  Dependency rows:   %d\n", stats.DependencyRows)
+	fmt.Printf("  Feature IDs set:   %d\n", stats.FeatureIDsSet)
+}

tools/go-analyzer/sqlite.go

@@ -152,3 +152,176 @@ func (w *DBWriter) insertLibrary(tx *sql.Tx, imp *ImportInfo) error {
 	)
 	return err
 }
+
+// OpenDBNoSchema opens an existing SQLite database without applying schema.
+// It verifies that the required tables exist.
+func OpenDBNoSchema(dbPath string) (*sql.DB, error) {
+	db, err := sql.Open("sqlite3", dbPath+"?_journal_mode=WAL&_foreign_keys=ON")
+	if err != nil {
+		return nil, fmt.Errorf("opening database: %w", err)
+	}
+
+	// Verify required tables exist
+	for _, table := range []string{"modules", "features", "unit_tests", "dependencies"} {
+		var name string
+		err := db.QueryRow("SELECT name FROM sqlite_master WHERE type='table' AND name=?", table).Scan(&name)
+		if err != nil {
+			db.Close()
+			return nil, fmt.Errorf("required table %q not found: %w", table, err)
+		}
+	}
+
+	return db, nil
+}
+
+// CallGraphStats holds summary statistics from a call-graph update.
+type CallGraphStats struct {
+	TestsAnalyzed  int
+	TestsLinked    int
+	DependencyRows int
+	FeatureIDsSet  int
+}
+
+// UpdateCallGraph writes call-graph analysis results to the database incrementally.
+func (w *DBWriter) UpdateCallGraph(result *AnalysisResult) (*CallGraphStats, error) {
+	stats := &CallGraphStats{}
+
+	// Load module name→ID mapping
+	moduleIDs := make(map[string]int64)
+	rows, err := w.db.Query("SELECT id, name FROM modules")
+	if err != nil {
+		return nil, fmt.Errorf("querying modules: %w", err)
+	}
+	for rows.Next() {
+		var id int64
+		var name string
+		if err := rows.Scan(&id, &name); err != nil {
+			rows.Close()
+			return nil, err
+		}
+		moduleIDs[name] = id
+	}
+	rows.Close()
+
+	// Load feature DB IDs: "module_name:go_method:go_class" → id
+	type featureKey struct {
+		moduleName string
+		goMethod   string
+		goClass    string
+	}
+	featureDBIDs := make(map[featureKey]int64)
+	rows, err = w.db.Query(`
+		SELECT f.id, m.name, f.go_method, COALESCE(f.go_class, '')
+		FROM features f
+		JOIN modules m ON f.module_id = m.id
+	`)
+	if err != nil {
+		return nil, fmt.Errorf("querying features: %w", err)
+	}
+	for rows.Next() {
+		var id int64
+		var modName, goMethod, goClass string
+		if err := rows.Scan(&id, &modName, &goMethod, &goClass); err != nil {
+			rows.Close()
+			return nil, err
+		}
+		featureDBIDs[featureKey{modName, goMethod, goClass}] = id
+	}
+	rows.Close()
+
+	// Load test DB IDs: "module_name:go_method" → id
+	testDBIDs := make(map[string]int64)
+	rows, err = w.db.Query(`
+		SELECT ut.id, m.name, ut.go_method
+		FROM unit_tests ut
+		JOIN modules m ON ut.module_id = m.id
+	`)
+	if err != nil {
+		return nil, fmt.Errorf("querying unit_tests: %w", err)
+	}
+	for rows.Next() {
+		var id int64
+		var modName, goMethod string
+		if err := rows.Scan(&id, &modName, &goMethod); err != nil {
+			rows.Close()
+			return nil, err
+		}
+		testDBIDs[modName+":"+goMethod] = id
+	}
+	rows.Close()
+
+	// Begin transaction
+	tx, err := w.db.Begin()
+	if err != nil {
+		return nil, fmt.Errorf("beginning transaction: %w", err)
+	}
+	defer tx.Rollback()
+
+	// Clear old call-graph data
+	if _, err := tx.Exec("DELETE FROM dependencies WHERE source_type='unit_test' AND dependency_kind='calls'"); err != nil {
+		return nil, fmt.Errorf("clearing old dependencies: %w", err)
+	}
+	if _, err := tx.Exec("UPDATE unit_tests SET feature_id = NULL"); err != nil {
+		return nil, fmt.Errorf("clearing old feature_ids: %w", err)
+	}
+
+	// Prepare statements
+	insertDep, err := tx.Prepare("INSERT OR IGNORE INTO dependencies (source_type, source_id, target_type, target_id, dependency_kind) VALUES ('unit_test', ?, 'feature', ?, 'calls')")
+	if err != nil {
+		return nil, fmt.Errorf("preparing insert dependency: %w", err)
+	}
+	defer insertDep.Close()
+
+	updateFeatureID, err := tx.Prepare("UPDATE unit_tests SET feature_id = ? WHERE id = ?")
+	if err != nil {
+		return nil, fmt.Errorf("preparing update feature_id: %w", err)
+	}
+	defer updateFeatureID.Close()
+
+	// Process each module's tests
+	for _, mod := range result.Modules {
+		for _, test := range mod.Tests {
+			stats.TestsAnalyzed++
+
+			testDBID, ok := testDBIDs[mod.Name+":"+test.GoMethod]
+			if !ok {
+				continue
+			}
+
+			// Insert dependency rows for linked features
+			if len(test.LinkedFeatures) > 0 {
+				stats.TestsLinked++
+			}
+			for _, fi := range test.LinkedFeatures {
+				feat := mod.Features[fi]
+				featDBID, ok := featureDBIDs[featureKey{mod.Name, feat.GoMethod, feat.GoClass}]
+				if !ok {
+					continue
+				}
+				if _, err := insertDep.Exec(testDBID, featDBID); err != nil {
+					return nil, fmt.Errorf("inserting dependency for test %s: %w", test.GoMethod, err)
+				}
+				stats.DependencyRows++
+			}
+
+			// Set feature_id for best match
+			if test.BestFeatureIdx >= 0 {
+				feat := mod.Features[test.BestFeatureIdx]
+				featDBID, ok := featureDBIDs[featureKey{mod.Name, feat.GoMethod, feat.GoClass}]
+				if !ok {
+					continue
+				}
+				if _, err := updateFeatureID.Exec(featDBID, testDBID); err != nil {
+					return nil, fmt.Errorf("updating feature_id for test %s: %w", test.GoMethod, err)
+				}
+				stats.FeatureIDsSet++
+			}
+		}
+	}
+
+	if err := tx.Commit(); err != nil {
+		return nil, fmt.Errorf("committing transaction: %w", err)
+	}
+
+	return stats, nil
+}

tools/go-analyzer/types.go

@@ -58,6 +58,28 @@ type TestFunc struct {
 	GoLineCount  int
 	// FeatureName links this test to a feature by naming convention
 	FeatureName string
+	// Calls holds raw function/method calls extracted from the test body AST
+	Calls []CallInfo
+	// LinkedFeatures holds indices into the parent module's Features slice
+	LinkedFeatures []int
+	// BestFeatureIdx is the primary feature match index (-1 = none)
+	BestFeatureIdx int
+}
+
+// CallInfo represents a function or method call extracted from a test body.
+type CallInfo struct {
+	FuncName   string // direct call name: "newMemStore"
+	RecvOrPkg  string // selector receiver/pkg: "ms", "fmt", "t"
+	MethodName string // selector method: "StoreMsg", "Fatalf"
+	IsSelector bool   // true for X.Y() form
+}
+
+// callKey returns a deduplication key for this call.
+func (c CallInfo) callKey() string {
+	if c.IsSelector {
+		return c.RecvOrPkg + "." + c.MethodName
+	}
+	return c.FuncName
 }
 
 // Dependency represents a call relationship between two items.