Resolve compiled .aimodelc assets when metadata references .aimodel

After `coreai-build compile` produces .aimodelc from .aimodel, the
metadata.json still references the original .aimodel name. This caused
silent load failures for all diffusion pipelines and required manual
metadata editing.

ModelBundle.resolveAssetURL now falls back from .aimodel to .aimodelc
when the declared path doesn't exist on disk. One-way only (source →
compiled), since the reverse would bypass an intentional user choice.

Applied to:
- ModelBundle.modelURL(for:) — LLMs, segmentation, VLMs
- ModelBundle.verify() — bundle validation
- SD3Pipeline+Resources — SD3 component loading
- PipelineDescriptor+CoreAI — SD 1.x/2.x component loading

Fixes #128

Author: stikves

swift/Sources/CoreAIDiffusionPipeline/Pipelines/PipelineDescriptor+CoreAI.swift

@@ -4,6 +4,7 @@
 // be found in the LICENSE file or at https://opensource.org/licenses/BSD-3-Clause
 
 import CoreAI
+import CoreAIShared
 import Foundation
 
 /// Loaded diffusion pipeline components backed by Core AI model functions.
@@ -51,14 +52,14 @@ extension PipelineDescriptor {
 
         // Create model functions
         let unetFunction = CoreAIDiffusionModelFunction(
-            modelURL: baseURL.appendingPathComponent(unetPath))
+            modelURL: ModelBundle.resolveAssetURL(unetPath, in: baseURL))
         let decoderFunction = CoreAIDiffusionModelFunction(
-            modelURL: baseURL.appendingPathComponent(decoderPath))
+            modelURL: ModelBundle.resolveAssetURL(decoderPath, in: baseURL))
 
         let encoderFunction: CoreAIDiffusionModelFunction?
         if let encoderPath = components.vaeEncoder {
             encoderFunction = CoreAIDiffusionModelFunction(
-                modelURL: baseURL.appendingPathComponent(encoderPath))
+                modelURL: ModelBundle.resolveAssetURL(encoderPath, in: baseURL))
         } else {
             encoderFunction = nil
         }
@@ -108,7 +109,7 @@ extension PipelineDescriptor {
         let textEncoderFunction: CoreAIDiffusionModelFunction
         if let tePath = components.textEncoder {
             textEncoderFunction = CoreAIDiffusionModelFunction(
-                modelURL: baseURL.appendingPathComponent(tePath))
+                modelURL: ModelBundle.resolveAssetURL(tePath, in: baseURL))
         } else {
             throw PipelineLoadError.missingComponent("text_encoder")
         }

swift/Sources/CoreAIDiffusionPipeline/Pipelines/SD3Pipeline+Resources.swift

@@ -4,6 +4,7 @@
 // be found in the LICENSE file or at https://opensource.org/licenses/BSD-3-Clause
 
 import CoreAI
+import CoreAIShared
 import Foundation
 
 extension SD3Pipeline {
@@ -29,13 +30,13 @@ extension SD3Pipeline {
         }
 
         let transformer = CoreAIDiffusionModelFunction(
-            modelURL: url.appendingPathComponent(transformerPath))
+            modelURL: ModelBundle.resolveAssetURL(transformerPath, in: url))
         let textEncoder = CoreAIDiffusionModelFunction(
-            modelURL: url.appendingPathComponent(textEncoderPath))
+            modelURL: ModelBundle.resolveAssetURL(textEncoderPath, in: url))
         let textEncoder2 = CoreAIDiffusionModelFunction(
-            modelURL: url.appendingPathComponent(textEncoder2Path))
+            modelURL: ModelBundle.resolveAssetURL(textEncoder2Path, in: url))
         let decoder = CoreAIDiffusionModelFunction(
-            modelURL: url.appendingPathComponent(decoderPath))
+            modelURL: ModelBundle.resolveAssetURL(decoderPath, in: url))
 
         let tokenizer = try Self.loadBPETokenizer(
             at: url.appendingPathComponent("tokenizer"))

swift/Sources/CoreAIShared/Bundle/ModelBundle.swift

@@ -48,9 +48,10 @@ public struct ModelBundle: Sendable {
     }
 
     /// Resolve a component's URL within the bundle by role key.
+    /// Falls back to `.aimodelc` if the declared `.aimodel` path doesn't exist on disk.
     public func modelURL(for key: String) -> URL? {
         guard let path = assets[key] else { return nil }
-        return bundlePath.appending(path: path)
+        return Self.resolveAssetURL(path, in: bundlePath)
     }
 
     /// Required-component variant — throws `BundleError.missingField` if absent.
@@ -61,13 +62,27 @@ public struct ModelBundle: Sendable {
         return url
     }
 
+    /// Resolve an asset path against a directory, falling back from `.aimodel` to `.aimodelc`.
+    ///
+    /// When `coreai-build compile` produces a compiled `.aimodelc` from a source `.aimodel`,
+    /// metadata.json still references the original name. This finds the compiled variant
+    /// so users don't need to hand-edit metadata.json after compilation.
+    public static func resolveAssetURL(_ path: String, in directory: URL) -> URL {
+        let url = directory.appending(path: path)
+        if FileManager.default.fileExists(atPath: url.path) { return url }
+        if path.hasSuffix(".aimodel") {
+            let compiled = directory.appending(path: path + "c")
+            if FileManager.default.fileExists(atPath: compiled.path) { return compiled }
+        }
+        return url
+    }
+
     /// Verify all declared assets exist on disk. Throws `BundleError.missingAsset`
     /// with guidance if a component is missing (e.g. after manual compilation).
     public func verify() throws {
-        let fm = FileManager.default
         for (key, filename) in assets {
-            let url = bundlePath.appending(path: filename)
-            if !fm.fileExists(atPath: url.path) {
+            let url = Self.resolveAssetURL(filename, in: bundlePath)
+            if !FileManager.default.fileExists(atPath: url.path) {
                 throw BundleError.missingAsset(key: key, path: url)
             }
         }