v0.2.4: Undefined class Mode in GCM.create(), Swift type mismatches remain

[fonkamloic]

Summary

auto_interop_generator v0.2.4 is close to working. Only 1 Dart analysis error in generated code (down from 12 in v0.2.3, 214 in v0.2.1). Swift glue now includes decoder helpers and type conversions, but several Swift-side issues prevent compilation.

Generator version: 0.2.4
Target package: CryptoSwift ~> 1.8 (CocoaPods, resolved to 1.8.4)
Flutter: 3.41.2 / Dart 3.11.0
Platform: iOS (iPhone 17 Pro simulator)

What's Fixed from v0.2.3 (Issue #3)

1. ✅ HMACVariant — Now a proper enum (was broken sealed class with missing subclasses)
2. ✅ GCM.create() syntax — `List??` double-optional fixed to `List?`
3. ✅ Swift decoder helpers generated — `decodeSHA2Variant()` and `decodePadding()` now present
4. ✅ Swift type conversion — `[Any].map { $0 as! Int }` added for List parameters

`flutter analyze` output (1 error in generated code)

```
error • Undefined class 'Mode' • lib/generated/cryptoswift.dart:406:131 • undefined_class
```

Plus 2 errors in user code (wrong import path — expected, user code needs updating once generated API stabilizes).

---

Issue 1 (DART): Undefined class `Mode` in `GCM.create()`

File: `lib/generated/cryptoswift.dart` line 406

```dart
static Future create({required List iv, required List authenticationTag, List? additionalAuthenticatedData, Mode? mode}) async {
```

The `Mode` opaque stub class (present in v0.2.3) was removed from v0.2.4, but `GCM.create()` still references it as a parameter type. Either:

• Keep `Mode` as an opaque stub (like `Variant`, `ArraySlice`, etc.)
• Or generate a proper `GCMMode` enum (like `SHA2Variant` and `HMACVariant` were generated):

```dart
enum GCMMode {
combined,
detached;
}
```

---

Issue 2 (SWIFT): `decodeSHA2Variant()` returns `SHA2Variant` but CryptoSwift uses `SHA2.Variant`

File: `ios/Runner/CryptoswiftPlugin.swift` line 41

```swift
private func decodeSHA2Variant(_ value: String) -> SHA2Variant {
```

CryptoSwift defines the variant as a nested type `SHA2.Variant`, not a top-level `SHA2Variant`:

```swift
// CryptoSwift source:
public struct SHA2: DigestType {
public enum Variant: RawRepresentable {
case sha224, sha256, sha384, sha512
}
}
```

The generated return type `SHA2Variant` doesn't exist in CryptoSwift's namespace. Should be:

```swift
private func decodeSHA2Variant(_ value: String) -> SHA2.Variant {
switch value {
case "sha224": return .sha224
// ...
}
}
```

---

Issue 3 (SWIFT): Type conversions produce `[Int]` instead of `[UInt8]`

File: `ios/Runner/CryptoswiftPlugin.swift` lines 73, 174, 235, etc.

```swift
let keyTyped = (key as [Any]).map { $0 as! Int } // Produces [Int]
```

CryptoSwift expects `Array` (i.e. `[UInt8]`) for keys, IVs, plaintext, etc. Should be:

```swift
let keyTyped = (key as [Any]).map { UInt8($0 as! Int) } // Produces [UInt8]
```

Affected cases: `AES._create`, `HMAC._create`, `HMAC.authenticate`, `SHA2.calculate`, `SHA2.callAsFunction`, `GCM._create`, `Authenticator.authenticate`.

---

Issue 4 (SWIFT): HMAC variant passed as `[String: Any]?` instead of `HMAC.Variant`

File: `ios/Runner/CryptoswiftPlugin.swift` line 175

```swift
case "HMAC._create":
let variant = args["variant"] as? [String: Any]
let instance = HMAC(key: keyTyped, variant: variant) // variant should be HMAC.Variant
```

CryptoSwift HMAC expects `variant: HMAC.Variant` (e.g., `.sha256`). Need a `decodeHMACVariant()` helper similar to `decodeSHA2Variant()`:

```swift
private func decodeHMACVariant(_ value: String) -> HMAC.Variant {
switch value {
case "sha256": return .sha256
case "sha384": return .sha384
case "sha512": return .sha512
case "md5": return .md5
case "sha1": return .sha1
default: fatalError("Unknown HMAC variant: \(value)")
}
}
```

---

Issue 5 (SWIFT): GCM mode passed as `[String: Any]?` instead of `GCM.Mode`

File: `ios/Runner/CryptoswiftPlugin.swift` line 306

```swift
let instance = GCM(iv: ivTyped, authenticationTag: authenticationTagTyped, additionalAuthenticatedData: additionalAuthenticatedDataTyped, mode: mode)
```

`mode` is `[String: Any]?` but CryptoSwift expects `GCM.Mode` enum (`.combined` or `.detached`).

---

Issue 6 (SWIFT): Missing `try` on throwing CryptoSwift initializers

```swift
case "AES._create":
let instance = AES(key: keyTyped, ...) // Should be: try AES(key: keyTyped, ...)

case "HMAC._create":
let instance = HMAC(key: keyTyped, ...) // Should be: try HMAC(key: keyTyped, ...)
```

---

Issue 7 (REMAINING): Generated Swift files not added to Xcode project

Same as v0.2.2 and v0.2.3. `CryptoswiftPlugin.swift` and `RegisterAutoInteropPlugins.swift` not in build phases.

---

Progress Summary

Issue	v0.2.1	v0.2.2	v0.2.3	v0.2.4
Doc comment formatting	❌ 150 errors	✅	✅	✅
Duplicate create methods	❌	✅	✅	✅
Interface class with fields	❌	✅	✅	✅
Dart create() factories	N/A	❌	✅	✅
Create cases return handles	N/A	❌	✅	✅
Swift init() constructors	❌	❌	✅	✅
HMACVariant definition	N/A	N/A	❌ sealed	✅ enum
GCM.create() syntax	N/A	N/A	❌ `??`	✅ Fixed
Swift decoder helpers	N/A	N/A	❌	✅ Added
Swift type conversion	❌	❌	❌	⚠️ [Int] not [UInt8]
Undefined class Mode	N/A	N/A	N/A	❌ NEW
Swift SHA2Variant vs SHA2.Variant	N/A	N/A	N/A	❌ NEW
Swift HMAC/GCM enum decoding	❌	❌	❌	❌
Swift files in Xcode	❌	❌	❌	❌
Dart analysis errors	214	0	12	1

Environment

• macOS 15.5 (Darwin 25.3.0)
• Flutter 3.41.2 / Dart 3.11.0
• Xcode 26.2
• CocoaPods 1.16.2
• CryptoSwift 1.8.4
• auto_interop 0.2.2
• auto_interop_generator 0.2.4

[github-actions]

Thanks for reporting this! The issue has been auto-labeled as bug, enhancement, question, platform: ios, area: generator and added to the triage queue.

[fonkamloic]

Tested with v0.2.5 — generated output is identical to v0.2.4. All issues in this ticket remain:

• Undefined class 'Mode' in GCM.create() (line 406) — still 1 Dart error
• Swift decodeSHA2Variant() returns SHA2Variant instead of SHA2.Variant
• Swift type conversions produce [Int] instead of [UInt8]
• HMAC variant / GCM mode not decoded to proper CryptoSwift enum types
• Missing try on throwing initializers
• Swift files not added to Xcode project

flutter analyze: 1 error in generated code (unchanged from v0.2.4)

[fonkamloic]

Tested with auto_interop 0.2.5 + auto_interop_generator 0.2.5 — generated output unchanged. All issues remain:

• Undefined class 'Mode' in GCM.create() — 1 Dart error in generated code
• Swift files not added to Xcode project
• Swift decodeSHA2Variant() returns SHA2Variant (should be SHA2.Variant)
• Swift type conversions produce [Int] instead of [UInt8]
• HMAC variant / GCM mode not decoded to CryptoSwift enum types
• Missing try on throwing initializers

The Mode class is the only remaining Dart blocker. Once that's either re-added as an opaque stub or replaced with a GCMMode enum, the Dart side will have 0 errors in generated code.