Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "jsondb"
-version = "0.1.1"
+version = "0.1.0"
 edition = "2021"
 authors = ["xenofem <xenofem@xeno.science>"]
 

src/lib.rs

@@ -47,12 +47,9 @@ pub struct JsonDb<T: Schema> {
 /// other fields of the corresponding schema version; earlier versions
 /// will be migrated to the current version automatically.
 pub trait Schema: DeserializeOwned + Serialize {
-    /// Previous schema that can be migrated into the new schema
+    const VERSION: u32;
     type Prev: Schema + Into<Self>;
 
-    /// Schema version number
-    const VERSION: u32 = Self::Prev::VERSION + 1;
-
     fn parse(s: &str) -> Result<Self, Error> {
         let Version { version } = serde_json::from_str(s)?;
         match version.cmp(&Self::VERSION) {
@@ -67,25 +64,11 @@ pub trait Schema: DeserializeOwned + Serialize {
 ///
 /// Implementing this will automatically implement [`Schema`], with
 /// version number `0` and `Self` as the previous version.
-pub trait SchemaV0: DeserializeOwned + Serialize {
+pub trait SchemaV0: DeserializeOwned + Serialize {}
-    /// Set this to false if your version 0 is a pre-`JsonDb` schema
-    /// that does not include a version number.
-    const EXPECT_VERSION_NUMBER: bool = true;
-}
 
 impl<T: SchemaV0> Schema for T {
-    type Prev = Self;
     const VERSION: u32 = 0;
-
+    type Prev = Self;
-    fn parse(s: &str) -> Result<Self, Error> {
-        if Self::EXPECT_VERSION_NUMBER {
-            let Version { version } = serde_json::from_str(s)?;
-            if version != 0 {
-                return Err(Error::UnknownVersion(version));
-            }
-        }
-        Ok(serde_json::from_str(s)?)
-    }
 }
 
 #[derive(Deserialize)]
@@ -233,6 +216,7 @@ mod tests {
         last_updated: i64,
     }
     impl Schema for V1 {
+        const VERSION: u32 = 1;
         type Prev = V0;
     }
     impl From<V0> for V1 {
@@ -264,6 +248,7 @@ mod tests {
         }
     }
     impl Schema for V2 {
+        const VERSION: u32 = 2;
         type Prev = V1;
     }
     impl From<V1> for V2 {