#[serde(flatten)] crashes when trying to serialize

[maxomatic458]

#[serde(rename = "AppState")]
struct AppManifestFile {
    #[serde(rename = "appid")]
    pub app_id: String,
    pub name: String,
    #[serde(rename = "AutoUpdateBehavior")]
    pub auto_update_bahavior: String,
    #[serde(flatten)]
    other: HashMap<String, Value>,
}

deserializing works.

but when converting this object back to a string, it panics with this message: Expected key, found: Some(ObjBegin)

[CosmicHorrorDev]

I believe on the latest version this should emit an error instead of panicking at least (unless you're the one panicking of course)

Can you update your repro with the definition for Value? keyvalues_parser::Value doesn't impl (De)Serialize (although it really should)

[CosmicHorrorDev]

Ope, spoke too soon. I haven't released those changes yet, so that's only on main atm

[maxomatic458]

just realized i used serde_json::Value, i think this might be what caused the panic.
In my case i need to have a "any" type there so i will just wait until Serialize is implemented for Value

then i will retest it

[maxomatic458]

hmm
i think that might not be the cause of the problem here

this also fails:

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename = "AppState")]
struct AppManifestFile {
    #[serde(rename = "appid")]
    pub app_id: String,
    pub name: String,
    #[serde(rename = "AutoUpdateBehavior")]
    pub auto_update_behavior: String,
    #[serde(flatten)]
    other: HashMap<String, String>,
}

this is the data:

"AppState"
{
	"AllowOtherDownloadsWhileRunning"	"0"
	"AutoUpdateBehavior"	"1"
	"BytesDownloaded"	"13772112"
	"BytesStaged"	"48688316"
	"BytesToDownload"	"13772112"
	"BytesToStage"	"48688316"
	"LastOwner"	"76561199134537034"
	"LastUpdated"	"1707501698"
	"LauncherPath"	"C:\\Program Files (x86)\\Steam\\steam.exe"
	"ScheduledAutoUpdate"	"0"
	"SizeOnDisk"	"36124234611"
	"StagingSize"	"0"
	"StateFlags"	"4"
	"TargetBuildID"	"13410341"
	"Universe"	"1"
	"UpdateResult"	"0"
	"appid"	"730"
	"buildid"	"13410341"
	"installdir"	"Counter-Strike Global Offensive"
	"name"	"Counter-Strike 2"
}

and here is a debug print of the AppManifest object:

AppManifestFile {
    app_id: "730",
    name: "Counter-Strike 2",
    auto_update_behavior: "1",
    other: {
        "LastOwner": "76561199134537034",
        "LastUpdated": "1707501698",
        "UpdateResult": "0",
        "BytesDownloaded": "13772112",
        "LauncherPath": "C:\\Program Files (x86)\\Steam\\steam.exe",
        "SizeOnDisk": "36124234611",
        "TargetBuildID": "13410341",
        "Universe": "1",
        "BytesToStage": "48688316",
        "BytesStaged": "48688316",
        "StagingSize": "0",
        "buildid": "13410341",
        "installdir": "Counter-Strike Global Offensive",
        "BytesToDownload": "13772112",
        "ScheduledAutoUpdate": "0",
        "StateFlags": "4",
        "AllowOtherDownloadsWhileRunning": "0",
    },
}

[CosmicHorrorDev]

Perfect, thanks! I'll try to figure out a fix sometime next week

[maxomatic458]

here is a full example:

use std::collections::HashMap;
use keyvalues_serde;
use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)]
struct Foo {
    #[serde(rename = "KnownField")]
    known_field: String,
    #[serde(rename = "KnownFieldTwo")]
    known_field_two: String,
    #[serde(flatten)]
    other: HashMap<String, String>
}

fn main() {
    let input = r##"
        "Foo"
        {
            "KnownField" "0"
            "KnownFieldTwo" "1"
            "UnknownField" "2"
        }
    "##;

    let serialized: Foo = keyvalues_serde::from_str(input).unwrap();
    let back_to_string = keyvalues_serde::to_string(&serialized).unwrap(); // panics here

}