feat!: remove strict length check on tuple deserialization (#35)

This should be handled by #[serde(deny_unknown_fields)] so it can also be used non-strict (for custom visitors/deserializers). Unfortunately this isn't supported upstream in serde yet, so we should work on that. Co-authored-by: Steven Allen <[email protected]>
ipld · Feb 13, 2025 · 89c6fcf · 89c6fcf
1 parent 8930ea8
commit 89c6fcf
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Showing 7 changed files with 429 additions and 47 deletions.
diff --git a/Cargo.toml b/Cargo.toml
@@ -16,14 +16,16 @@ edition = "2018"
 
 [dependencies]
 cbor4ii = { version = "0.2.14", default-features = false, features = ["use_alloc"] }
-ipld-core = { version = "0.4.0", default-features = false, features = ["serde"] }
+ipld-core = { version = "0.4.2", default-features = false, features = ["serde"] }
 scopeguard = "1.1.0"
 serde = { version = "1.0.164", default-features = false, features = ["alloc"] }
 
 [dev-dependencies]
 serde_derive = { version = "1.0.164", default-features = false }
 serde_bytes = { version = "0.11.9", default-features = false, features = ["alloc"]}
 serde-transcode = "1.1.1"
+const-hex = "1.14.0"
+serde_tuple = "1.1.0"
 
 [features]
 default = ["codec", "std"]

diff --git a/examples/enums.rs b/examples/enums.rs
@@ -6,7 +6,6 @@ use std::convert::{TryFrom, TryInto};
 use ipld_core::{cid::Cid, ipld::Ipld};
 use serde::{de, Deserialize};
 use serde_bytes::ByteBuf;
-use serde_derive::Deserialize;
 use serde_ipld_dagcbor::from_slice;
 
 /// The CID `bafkreibme22gw2h7y2h7tg2fhqotaqjucnbc24deqo72b6mkl2egezxhvy` encoded as CBOR

diff --git a/src/de.rs b/src/de.rs
@@ -143,6 +143,50 @@ impl<'de, R: dec::Read<'de>> Deserializer<R> {
             Err(error) => Err(error),
         }
     }
+
+    fn visit_seq<V>(
+        &mut self,
+        name: &'static str,
+        visitor: V,
+    ) -> Result<V::Value, DecodeError<R::Error>>
+    where
+        V: Visitor<'de>,
+    {
+        let mut de = self.try_step()?;
+        let mut seq = Accessor::array(&mut de)?;
+        let value = seq.len;
+        let res = visitor.visit_seq(&mut seq)?;
+        match seq.len {
+            0 => Ok(res),
+            remaining => Err(DecodeError::RequireLength {
+                name,
+                expect: value - remaining,
+                value,
+            }),
+        }
+    }
+
+    fn visit_map<V>(
+        &mut self,
+        name: &'static str,
+        visitor: V,
+    ) -> Result<V::Value, DecodeError<R::Error>>
+    where
+        V: Visitor<'de>,
+    {
+        let mut de = self.try_step()?;
+        let mut map = Accessor::map(&mut de)?;
+        let value = map.len;
+        let res = visitor.visit_map(&mut map)?;
+        match map.len {
+            0 => Ok(res),
+            remaining => Err(DecodeError::RequireLength {
+                name,
+                expect: value - remaining,
+                value,
+            }),
+        }
+    }
 }
 
 macro_rules! deserialize_type {
@@ -162,7 +206,7 @@ macro_rules! deserialize_type {
     };
 }
 
-impl<'de, 'a, R: dec::Read<'de>> serde::Deserializer<'de> for &'a mut Deserializer<R> {
+impl<'de, R: dec::Read<'de>> serde::Deserializer<'de> for &mut Deserializer<R> {
     type Error = DecodeError<R::Error>;
 
     fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
@@ -343,55 +387,49 @@ impl<'de, 'a, R: dec::Read<'de>> serde::Deserializer<'de> for &'a mut Deserializ
     where
         V: Visitor<'de>,
     {
-        let mut de = self.try_step()?;
-        let seq = Accessor::array(&mut de)?;
-        visitor.visit_seq(seq)
+        self.visit_seq("array", visitor)
     }
 
     #[inline]
-    fn deserialize_tuple<V>(self, len: usize, visitor: V) -> Result<V::Value, Self::Error>
+    fn deserialize_tuple<V>(self, _len: usize, visitor: V) -> Result<V::Value, Self::Error>
     where
         V: Visitor<'de>,
     {
-        let mut de = self.try_step()?;
-        let seq = Accessor::tuple(&mut de, len)?;
-        visitor.visit_seq(seq)
+        self.visit_seq("tuple", visitor)
     }
 
     #[inline]
     fn deserialize_tuple_struct<V>(
         self,
-        _name: &'static str,
-        len: usize,
+        name: &'static str,
+        _len: usize,
         visitor: V,
     ) -> Result<V::Value, Self::Error>
     where
         V: Visitor<'de>,
     {
-        self.deserialize_tuple(len, visitor)
+        self.visit_seq(name, visitor)
     }
 
     #[inline]
     fn deserialize_map<V>(self, visitor: V) -> Result<V::Value, Self::Error>
     where
         V: Visitor<'de>,
     {
-        let mut de = self.try_step()?;
-        let map = Accessor::map(&mut de)?;
-        visitor.visit_map(map)
+        self.visit_map("map", visitor)
     }
 
     #[inline]
     fn deserialize_struct<V>(
         self,
-        _name: &'static str,
+        name: &'static str,
         _fields: &'static [&'static str],
         visitor: V,
     ) -> Result<V::Value, Self::Error>
     where
         V: Visitor<'de>,
     {
-        self.deserialize_map(visitor)
+        self.visit_map(name, visitor)
     }
 
     #[inline]
@@ -439,7 +477,7 @@ struct Accessor<'a, R> {
 
 impl<'de, 'a, R: dec::Read<'de>> Accessor<'a, R> {
     #[inline]
-    pub fn array(de: &'a mut Deserializer<R>) -> Result<Accessor<'a, R>, DecodeError<R::Error>> {
+    fn array(de: &'a mut Deserializer<R>) -> Result<Accessor<'a, R>, DecodeError<R::Error>> {
         let array_start = dec::ArrayStart::decode(&mut de.reader)?;
         array_start.0.map_or_else(
             || Err(DecodeError::IndefiniteSize),
@@ -448,25 +486,7 @@ impl<'de, 'a, R: dec::Read<'de>> Accessor<'a, R> {
     }
 
     #[inline]
-    pub fn tuple(
-        de: &'a mut Deserializer<R>,
-        len: usize,
-    ) -> Result<Accessor<'a, R>, DecodeError<R::Error>> {
-        let array_start = dec::ArrayStart::decode(&mut de.reader)?;
-
-        if array_start.0 == Some(len) {
-            Ok(Accessor { de, len })
-        } else {
-            Err(DecodeError::RequireLength {
-                name: "tuple",
-                expect: len,
-                value: array_start.0.unwrap_or(0),
-            })
-        }
-    }
-
-    #[inline]
-    pub fn map(de: &'a mut Deserializer<R>) -> Result<Accessor<'a, R>, DecodeError<R::Error>> {
+    fn map(de: &'a mut Deserializer<R>) -> Result<Accessor<'a, R>, DecodeError<R::Error>> {
         let map_start = dec::MapStart::decode(&mut de.reader)?;
         map_start.0.map_or_else(
             || Err(DecodeError::IndefiniteSize),
@@ -475,7 +495,7 @@ impl<'de, 'a, R: dec::Read<'de>> Accessor<'a, R> {
     }
 }
 
-impl<'de, 'a, R> de::SeqAccess<'de> for Accessor<'a, R>
+impl<'de, R> de::SeqAccess<'de> for Accessor<'_, R>
 where
     R: dec::Read<'de>,
 {
@@ -500,7 +520,7 @@ where
     }
 }
 
-impl<'de, 'a, R: dec::Read<'de>> de::MapAccess<'de> for Accessor<'a, R> {
+impl<'de, R: dec::Read<'de>> de::MapAccess<'de> for Accessor<'_, R> {
     type Error = DecodeError<R::Error>;
 
     #[inline]
@@ -570,7 +590,7 @@ where
     }
 }
 
-impl<'de, 'a, R> de::VariantAccess<'de> for EnumAccessor<'a, R>
+impl<'de, R> de::VariantAccess<'de> for EnumAccessor<'_, R>
 where
     R: dec::Read<'de>,
 {

diff --git a/src/error.rs b/src/error.rs
@@ -67,7 +67,7 @@ impl<E: fmt::Debug> From<cbor4ii::EncodeError<E>> for EncodeError<E> {
 }
 
 /// A decoding error.
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 pub enum DecodeError<E> {
     /// Custom error message.
     Msg(String),
@@ -101,7 +101,8 @@ pub enum DecodeError<E> {
         /// Type name (e.g. "bytes", "str").
         name: &'static str,
     },
-    /// Length wasn't large enough.
+    /// Length wasn't large enough. This error comes after attempting to consume the entirety of a
+    /// item with a known length and failing to do so.
     RequireLength {
         /// Type name.
         name: &'static str,