Zon support.

README.md

@@ -68,8 +68,6 @@ pub fn build(b: *std.Build) void {
             .root_source_file = b.path("src/lib.zig"),
             .target = target,
             .optimize = optimize,
-            .link_libc = true,
-            .pic = true,
         }),
     });
 
@@ -93,8 +91,6 @@ pub fn build(b: *std.Build) void {
         .root_source_file = b.path("src/lib.zig"),
         .target = target,
         .optimize = optimize,
-        .link_libc = true,
-        .pic = true,
     });
 
     // Dynamic library (.so, .dylib, .dll)
@@ -144,8 +140,6 @@ pub fn build(b: *std.Build) void {
             .root_source_file = b.path("src/lib.zig"),
             .target = target,
             .optimize = optimize,
-            .link_libc = true,
-            .pic = true,
         }),
     });
 
@@ -163,6 +157,7 @@ Build with: `zig build -Dlinkage=static` or `zig build -Dlinkage=dynamic`
     .name = .my_package,
     .version = "0.1.0",
     .minimum_zig_version = "0.15.0",
+    .fingerprint = 0x..........,
     .paths = .{
         "src",
         "build.zig",
@@ -171,6 +166,16 @@ Build with: `zig build -Dlinkage=static` or `zig build -Dlinkage=dynamic`
 }
 ```
 
+> [!IMPORTANT]
+> The `paths` field drives **incremental build tracking**. `ZigBuilder` parses
+> `build.zig.zon` and registers every file and directory listed in `paths` as a
+> build dependency. When any of those files change, Dart's build system
+> automatically re-triggers the Zig build. Make sure `paths` includes all source
+> directories and files your build depends on (e.g. `"src"`, C headers,
+> embedded data files).
+>
+> The `name` field (`.my_package`) is a comptime enum literal and is ignored.
+
 5. Create `zig/src/lib.zig`:
 ```zig
 export fn add(a: i32, b: i32) i32 {
@@ -205,4 +210,4 @@ MIT License - see [LICENSE](LICENSE) for details.
 
 <!-- Links -->
 [dart_hooks]: https://dart.dev/tools/hooks
-[zig_download]: https://ziglang.org/download/
+[zig_download]: https://ziglang.org/download/

lib/src/builder.dart

@@ -4,11 +4,11 @@ import 'package:code_assets/code_assets.dart';
 import 'package:hooks/hooks.dart';
 import 'package:logging/logging.dart';
 import 'package:native_toolchain_zig/src/code_config_mapping.dart';
+import 'package:native_toolchain_zig/src/target.dart';
+import 'package:native_toolchain_zig/src/utils.dart' as utils;
+import 'package:native_toolchain_zig/src/zon_parser.dart';
 import 'package:path/path.dart' as path;
 
-import 'target.dart';
-import 'utils.dart' as utils;
-
 /// Builds Zig code as native assets using `zig build`.
 ///
 /// Integrates with Dart's build hooks to automatically compile Zig code
@@ -129,8 +129,8 @@ class ZigBuilder implements Builder {
     );
 
     if (result.exitCode != 0) {
-      String stderr = result.stderr as String;
       String stdout = result.stdout as String;
+      String stderr = result.stderr as String;
       logger.severe('Build failed:\n$stderr\n$stdout');
       throw BuildError(
         message:
@@ -146,18 +146,51 @@ class ZigBuilder implements Builder {
     }
 
     String libName = libraryName ?? packageName;
-    Uri libPath = await _locateLibrary(input.outputDirectory, libName, target);
+    Uri libPath = _locateLibrary(input.outputDirectory, libName, target);
 
     output.dependencies.add(buildZig.uri);
 
     File buildZigZon = File(path.join(zigDirectory, 'build.zig.zon'));
 
     if (buildZigZon.existsSync()) {
       output.dependencies.add(buildZigZon.uri);
-    }
 
-    for (File file in utils.listZigFiles(zigDirectory)) {
-      output.dependencies.add(file.uri);
+      // To compile itself.
+      // TODO(build.zig.zon): write ZON parser in Dart.
+      if (packageName != 'native_toolchain_zig') {
+        // Validate?
+        Object? zon = parseZon(buildZigZon.readAsStringSync());
+
+        if (zon case {'paths': List<Object?> zonPaths}) {
+          for (Object? entry in zonPaths) {
+            if (entry is! String) {
+              continue;
+            }
+
+            // build.zig and build.zig.zon are already tracked above.
+            if (entry == 'build.zig' || entry == 'build.zig.zon') {
+              continue;
+            }
+
+            String fullPath = path.join(zigDirectory, entry);
+            FileSystemEntityType type = FileSystemEntity.typeSync(fullPath);
+
+            if (type == FileSystemEntityType.file) {
+              output.dependencies.add(Uri.file(fullPath));
+            } else if (type == FileSystemEntityType.directory) {
+              List<FileSystemEntity> entities = Directory(
+                fullPath,
+              ).listSync(recursive: true);
+
+              for (FileSystemEntity entity in entities) {
+                if (entity is File) {
+                  output.dependencies.add(entity.uri);
+                }
+              }
+            }
+          }
+        }
+      }
     }
 
     for (AssetRouting routing in assetRouting) {
@@ -176,7 +209,7 @@ class ZigBuilder implements Builder {
   }
 }
 
-Future<Uri> _locateLibrary(Uri outputDir, String libName, Target target) async {
+Uri _locateLibrary(Uri outputDir, String libName, Target target) {
   String fileName = target.libraryFileName(libName);
 
   List<Uri> searchPaths = <Uri>[