support for generic array type

[djdevin]

Apparently, this is necessary for some games. Some functionality breakage occurred comparing Photon Cloud with Luxon:

[warning] Invalid packet (4210 bytes in length) received: unsupported generic array element type

Will do some more testing

[niansa]

Thanks! Can you give me a list of games you've seen this occur with? This is GP binary v1.6 specific, which makes sense since that one isn't tested by far as well as V1.8 and I don't have enough games using it so I haven't been able to figure out all the data types yet. This seems to be one of them.

[djdevin]

I reported before that Rec Room (2023) works - which it does! But some functionality doesn't specifically involving room creation.

For example a user joining a room with an unpublished unity asset sees the published version, which causes desync issues as the room owner sees something different.

I dug into the game client (with Claude) and came up with:

(a) The invitee isn't landing in the owner's Photon room. If matchmake/player/187 mints a fresh instance instead of returning the one the target is currently in, the joiner creates a new room, "pl" is absent, and it loads currentSave — the base room. Exactly your symptom.

Test: compare photonRoomId and roomInstanceId in the matchmake response against what the owner is actually in. In the payload you pasted, photonRoomId was be538576-23ee-408f-9cef-51c493d781de — if that differs from the owner's, this is it.

(b) The "pl" property isn't surviving your Photon server. It's a byte[] custom property. If your server drops unknown room properties, doesn't replicate them to late joiners, or coerces the type, the joiner has nothing to read — same outcome.

I confirmed it's not (a) as players can see and talk to eachother so I think it's (b) as that error message appears in the Luxon logs when the user joins an unpublished room.

Also confirmed that using Photon Cloud, it works as intended.

Let me know how I can help by providing data dumps or something.

[niansa]

Yup! Please. Can you build Luxon Server with build type "Debug", trigger the issue and upload its standard output? It will include all the data transmitted to and from luxon server so please be aware that you might have to censor stuff like authentication tokens in it if relevant.

In case you don't know how to create such a build, tell me which operating system and architecture you're running this on and I'll upload a debug build here.

[djdevin]

I blindly told Claude to build out generic arrays and it fixed the issue, so there is hope. I don't want to clutter your repository with AI so I will get debug dumps on the current version.

[niansa]

Well if Claude was able to do it without any packet dumps it's probably very straight forward. I'd still like to see some to verify but this is going to be easy

[djdevin]

Here is some before and after the error

[2026-08-10 02:14:20.960] [Peer 13@72.78.65.244:49586] [trace] Received message using mode 1 on channel 0:
    >>> OPERATION REQUEST
    OpCode: 253
    Parameters (4):
      [244]:
        22 (8 bits)
      [245]:
        hashtable[6]:
          key:
            "pl"
          value:
            byte[22]: 08 02 12 10 a0 ac 20 a8 da ff f7 4d 85 56 06 1f a2 c1 fc 8a 18 0c 
          key:
            "rlid"
          value:
            "e4909cf1-be98-5ae6-8f12-e9d4c60532aa"
          key:
            "mid"
          value:
            "4d641e05-e6e2-4ce8-89b4-985d2ea9c432"
          key:
            "midb"
          value:
            18 (8 bits)
          key:
            "sidb"
          value:
            1 (8 bits)
          key:
            "st"
          value:
            6 (8 bits)
      [246]:
        1 (8 bits)
      [247]:
        5 (8 bits)

[2026-08-10 02:14:20.960] [Peer 13@72.78.65.244:49586] [trace] Sending message using mode 1 on channel 0:
    <<< EVENT
    EventCode: 22
    Parameters (2):
      [245]:
        hashtable[6]:
          key:
            "st"
          value:
            6 (8 bits)
          key:
            "sidb"
          value:
            1 (8 bits)
          key:
            "midb"
          value:
            18 (8 bits)
          key:
            "mid"
          value:
            "4d641e05-e6e2-4ce8-89b4-985d2ea9c432"
          key:
            "rlid"
          value:
            "e4909cf1-be98-5ae6-8f12-e9d4c60532aa"
          key:
            "pl"
          value:
            byte[22]: 08 02 12 10 a0 ac 20 a8 da ff f7 4d 85 56 06 1f a2 c1 fc 8a 18 0c 
      [254]:
        1 (32 bits)

[2026-08-10 02:14:21.039] [Peer 13@72.78.65.244:49586] [trace] Received message using mode 1 on channel 0:
    ser decode failed: Error(code=4, msg="unsupported generic array element type")
[2026-08-10 02:14:21.039] [Peer 13@72.78.65.244:49586] [error] Message not understood!
    [ f3 02 fd 00 03 f7 62 05 f4 62 01 f5 68 00 02 62 00 69 00 01 86 a4 62 01 79 00 08 68 00 05 62 00 73 00 0e 5b 47 61 6d 65 52 6f 6c 65 4e 6f 64 65 5d 62 01 63 56 00 0c c0 28 4b da 3f 7f ff ef c0 41 ab 1f 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 04 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 00 1e e5 3d e9 aa 29 4c aa 33 d7 09 4d 2b 52 c1 00 06 43 4f 5f 53 54 54 69 00 00 00 bc 00 05 43 4f 5f 43 4e 69 00 00 00 03 00 07 67 72 6e 5f 72 69 64 73 00 24 32 63 37 32 31 33 34 32 2d 63 37 65 64 2d 34 39 66 65 2d 62 38 66 30 2d 39 33 66 38 64 32 38 32 61 36 64 66 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 90 00 05 62 00 73 00 1a 5b 53 74 61 6e 64 61 6c 6f 6e 65 53 68 61 70 65 43 6f 6e 74 61 69 6e 65 72 5d 62 01 63 56 00 0c bf 80 00 00 3f c0 00 00 00 00 00 00 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 02 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 e5 62 12 06 64 f1 08 44 a7 a7 5f 29 2b d0 17 b4 00 06 43 4f 5f 53 54 54 69 00 00 01 d4 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 91 00 05 62 00 73 00 1a 5b 53 74 61 6e 64 61 6c 6f 6e 65 53 68 61 70 65 43 6f 6e 74 61 69 6e 65 72 5d 62 01 63 56 00 0c c0 20 00 00 3f c0 00 00 3f 00 00 00 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 02 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 f4 9f 19 ec 6c f0 f3 48 b1 fe b8 fe 3d 72 31 7c 00 06 43 4f 5f 53 54 54 69 00 00 01 d4 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 92 00 07 62 00 73 00 11 28 53 61 6e 64 62 6f 78 5f 54 65 78 74 5f 56 33 29 62 01 63 56 00 0c bf dc d1 4f 3f b6 90 01 c0 60 6c c9 62 02 63 52 00 10 00 00 00 00 3f 80 00 00 00 00 00 00 00 00 00 00 62 09 63 56 00 0c 3d 6a ec 33 3d 6a ec 33 3d 6a ec 33 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 05 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 fc 59 87 43 25 a3 ae 4a 8a 6b 83 22 10 3c 48 e6 00 06 43 4f 5f 53 54 54 69 00 00 01 ba 00 07 63 76 32 5f 63 70 69 63 47 00 10 e0 fa ba c0 b8 f0 47 4c b3 db 62 eb 97 2c 0e 0c 00 07 63 76 32 5f 63 70 64 6f 01 00 07 63 76 32 5f 63 70 70 63 47 00 10 f2 ed c5 ea a1 e5 52 50 b9 d1 c8 5a 28 23 45 b9 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 93 00 05 62 00 73 00 0e 5b 47 61 6d 65 52 6f 6c 65 4e 6f 64 65 5d 62 01 63 56 00 0c c0 1b 7f 0d 3f 7f ff ef c0 41 ab 1f 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 04 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 93 68 84 13 61 cb b1 40 80 e9 4b 87 b3 6c fc 2c 00 06 43 4f 5f 53 54 54 69 00 00 00 bc 00 05 43 4f 5f 43 4e 69 00 00 00 05 00 07 67 72 6e 5f 72 69 64 73 00 24 30 62 39 65 63 33 39 65 2d 32 63 63 39 2d 34 38 32 35 2d 38 33 32 31 2d 64 61 31 31 35 36 31 66 31 63 34 66 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 94 00 05 62 00 73 00 1a 5b 53 74 61 6e 64 61 6c 6f 6e 65 53 68 61 70 65 43 6f 6e 74 61 69 6e 65 72 5d 62 01 63 56 00 0c 00 00 00 00 3f c0 00 00 00 00 00 00 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 02 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 a8 18 61 7b 04 2d 30 44 8d 0e e1 7b c9 1d cf a9 00 06 43 4f 5f 53 54 54 69 00 00 01 d4 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 95 00 05 62 00 73 00 0e 5b 47 61 6d 65 52 6f 6c 65 4e 6f 64 65 5d 62 01 63 56 00 0c c0 35 18 a7 3f 7f ff ef c0 41 ab 1f 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 04 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 00 3b 8d b3 1d 51 ce 41 b0 f5 f1 00 ff 2c 33 b3 00 06 43 4f 5f 53 54 54 69 00 00 00 bc 00 05 43 4f 5f 43 4e 69 00 00 00 01 00 07 67 72 6e 5f 72 69 64 73 00 24 63 34 38 62 61 63 30 32 2d 61 37 34 33 2d 34 37 39 37 2d 39 34 63 34 2d 65 32 64 36 66 30 37 34 39 30 30 34 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 96 00 07 62 00 73 00 11 28 53 61 6e 64 62 6f 78 5f 54 65 78 74 5f 56 33 29 62 01 63 56 00 0c be e6 66 66 3f bc 28 f6 c0 20 09 78 62 02 63 52 00 10 00 00 00 00 3f 80 00 00 00 00 00 00 00 00 00 00 62 09 63 56 00 0c 40 0e 38 e3 40 0e 38 e3 40 0e 38 e3 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 05 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 77 81 09 ad 51 78 51 47 bf 75 0d 25 65 d1 b1 3f 00 06 43 4f 5f 53 54 54 69 00 00 01 ba 00 07 63 76 32 5f 63 70 69 63 47 00 10 20 73 3a 95 c2 58 b3 40 84 d7 f1 32 61 b1 f3 00 00 07 63 76 32 5f 63 70 64 6f 01 00 07 63 76 32 5f 63 70 70 63 47 00 10 f2 ed c5 ea a1 e5 52 50 b9 d1 c8 5a 28 23 45 b9 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 97 ]
[2026-08-10 02:14:21.039] [Peer 13@72.78.65.244:49586] [warning] Invalid packet (1364 bytes in length) received: unsupported generic array element type
    [ f3 02 fd 00 03 f7 62 05 f4 62 01 f5 68 00 02 62 00 69 00 01 86 a4 62 01 79 00 08 68 00 05 62 00 73 00 0e 5b 47 61 6d 65 52 6f 6c 65 4e 6f 64 65 5d 62 01 63 56 00 0c c0 28 4b da 3f 7f ff ef c0 41 ab 1f 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 04 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 00 1e e5 3d e9 aa 29 4c aa 33 d7 09 4d 2b 52 c1 00 06 43 4f 5f 53 54 54 69 00 00 00 bc 00 05 43 4f 5f 43 4e 69 00 00 00 03 00 07 67 72 6e 5f 72 69 64 73 00 24 32 63 37 32 31 33 34 32 2d 63 37 65 64 2d 34 39 66 65 2d 62 38 66 30 2d 39 33 66 38 64 32 38 32 61 36 64 66 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 90 00 05 62 00 73 00 1a 5b 53 74 61 6e 64 61 6c 6f 6e 65 53 68 61 70 65 43 6f 6e 74 61 69 6e 65 72 5d 62 01 63 56 00 0c bf 80 00 00 3f c0 00 00 00 00 00 00 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 02 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 e5 62 12 06 64 f1 08 44 a7 a7 5f 29 2b d0 17 b4 00 06 43 4f 5f 53 54 54 69 00 00 01 d4 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 91 00 05 62 00 73 00 1a 5b 53 74 61 6e 64 61 6c 6f 6e 65 53 68 61 70 65 43 6f 6e 74 61 69 6e 65 72 5d 62 01 63 56 00 0c c0 20 00 00 3f c0 00 00 3f 00 00 00 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 02 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 f4 9f 19 ec 6c f0 f3 48 b1 fe b8 fe 3d 72 31 7c 00 06 43 4f 5f 53 54 54 69 00 00 01 d4 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 92 00 07 62 00 73 00 11 28 53 61 6e 64 62 6f 78 5f 54 65 78 74 5f 56 33 29 62 01 63 56 00 0c bf dc d1 4f 3f b6 90 01 c0 60 6c c9 62 02 63 52 00 10 00 00 00 00 3f 80 00 00 00 00 00 00 00 00 00 00 62 09 63 56 00 0c 3d 6a ec 33 3d 6a ec 33 3d 6a ec 33 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 05 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 fc 59 87 43 25 a3 ae 4a 8a 6b 83 22 10 3c 48 e6 00 06 43 4f 5f 53 54 54 69 00 00 01 ba 00 07 63 76 32 5f 63 70 69 63 47 00 10 e0 fa ba c0 b8 f0 47 4c b3 db 62 eb 97 2c 0e 0c 00 07 63 76 32 5f 63 70 64 6f 01 00 07 63 76 32 5f 63 70 70 63 47 00 10 f2 ed c5 ea a1 e5 52 50 b9 d1 c8 5a 28 23 45 b9 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 93 00 05 62 00 73 00 0e 5b 47 61 6d 65 52 6f 6c 65 4e 6f 64 65 5d 62 01 63 56 00 0c c0 1b 7f 0d 3f 7f ff ef c0 41 ab 1f 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 04 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 93 68 84 13 61 cb b1 40 80 e9 4b 87 b3 6c fc 2c 00 06 43 4f 5f 53 54 54 69 00 00 00 bc 00 05 43 4f 5f 43 4e 69 00 00 00 05 00 07 67 72 6e 5f 72 69 64 73 00 24 30 62 39 65 63 33 39 65 2d 32 63 63 39 2d 34 38 32 35 2d 38 33 32 31 2d 64 61 31 31 35 36 31 66 31 63 34 66 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 94 00 05 62 00 73 00 1a 5b 53 74 61 6e 64 61 6c 6f 6e 65 53 68 61 70 65 43 6f 6e 74 61 69 6e 65 72 5d 62 01 63 56 00 0c 00 00 00 00 3f c0 00 00 00 00 00 00 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 02 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 a8 18 61 7b 04 2d 30 44 8d 0e e1 7b c9 1d cf a9 00 06 43 4f 5f 53 54 54 69 00 00 01 d4 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 95 00 05 62 00 73 00 0e 5b 47 61 6d 65 52 6f 6c 65 4e 6f 64 65 5d 62 01 63 56 00 0c c0 35 18 a7 3f 7f ff ef c0 41 ab 1f 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 04 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 00 3b 8d b3 1d 51 ce 41 b0 f5 f1 00 ff 2c 33 b3 00 06 43 4f 5f 53 54 54 69 00 00 00 bc 00 05 43 4f 5f 43 4e 69 00 00 00 01 00 07 67 72 6e 5f 72 69 64 73 00 24 63 34 38 62 61 63 30 32 2d 61 37 34 33 2d 34 37 39 37 2d 39 34 63 34 2d 65 32 64 36 66 30 37 34 39 30 30 34 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 96 00 07 62 00 73 00 11 28 53 61 6e 64 62 6f 78 5f 54 65 78 74 5f 56 33 29 62 01 63 56 00 0c be e6 66 66 3f bc 28 f6 c0 20 09 78 62 02 63 52 00 10 00 00 00 00 3f 80 00 00 00 00 00 00 00 00 00 00 62 09 63 56 00 0c 40 0e 38 e3 40 0e 38 e3 40 0e 38 e3 62 05 7a 00 02 69 00 00 00 07 44 73 00 00 05 00 09 52 52 49 52 5f 50 56 49 44 63 47 00 10 77 81 09 ad 51 78 51 47 bf 75 0d 25 65 d1 b1 3f 00 06 43 4f 5f 53 54 54 69 00 00 01 ba 00 07 63 76 32 5f 63 70 69 63 47 00 10 20 73 3a 95 c2 58 b3 40 84 d7 f1 32 61 b1 f3 00 00 07 63 76 32 5f 63 70 64 6f 01 00 07 63 76 32 5f 63 70 70 63 47 00 10 f2 ed c5 ea a1 e5 52 50 b9 d1 c8 5a 28 23 45 b9 62 06 69 00 04 d4 0b 62 07 69 00 01 5f 97 ]
[2026-08-10 02:14:21.040] [Peer 13@72.78.65.244:49586] [trace] Received message using mode 1 on channel 0:
    >>> OPERATION REQUEST
    OpCode: 253
    Parameters (4):
      [244]:
        22 (8 bits)
      [245]:
        hashtable[6]:
          key:
            "pl"
          value:
            byte[20]: 08 03 12 10 a0 ac 20 a8 da ff f7 4d 85 56 06 1f a2 c1 fc 8a 
          key:
            "rlid"
          value:
            "e4909cf1-be98-5ae6-8f12-e9d4c60532aa"
          key:
            "mid"
          value:
            "4d641e05-e6e2-4ce8-89b4-985d2ea9c432"
          key:
            "midb"
          value:
            19 (8 bits)
          key:
            "sidb"
          value:
            1 (8 bits)
          key:
            "st"
          value:
            6 (8 bits)
      [246]:
        1 (8 bits)
      [247]:
        5 (8 bits)

[2026-08-10 02:14:21.040] [Peer 13@72.78.65.244:49586] [trace] Sending message using mode 1 on channel 0:
    <<< EVENT
    EventCode: 22
    Parameters (2):
      [245]:
        hashtable[6]:
          key:
            "st"
          value:
            6 (8 bits)
          key:
            "sidb"
          value:
            1 (8 bits)
          key:
            "midb"
          value:
            19 (8 bits)
          key:
            "mid"
          value:
            "4d641e05-e6e2-4ce8-89b4-985d2ea9c432"
          key:
            "rlid"
          value:
            "e4909cf1-be98-5ae6-8f12-e9d4c60532aa"
          key:
            "pl"
          value:
            byte[20]: 08 03 12 10 a0 ac 20 a8 da ff f7 4d 85 56 06 1f a2 c1 fc 8a 
      [254]:
        1 (32 bits)

[niansa]

Thank you!