Release 1.0.168

Allow larger preallocated capacity for smaller elements

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "1.0.167" # remember to update html_root_url and serde_derive dependency
+version = "1.0.168" # remember to update html_root_url and serde_derive dependency
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
 categories = ["encoding", "no-std", "no-std::no-alloc"]
@@ -15,7 +15,7 @@ repository = "https://github.com/serde-rs/serde"
 rust-version = "1.19"
 
 [dependencies]
-serde_derive = { version = "=1.0.167", optional = true, path = "../serde_derive" }
+serde_derive = { version = "=1.0.168", optional = true, path = "../serde_derive" }
 
 [dev-dependencies]
 serde_derive = { version = "1.0", path = "../serde_derive" }

serde/src/de/ignored_any.rs

@@ -107,7 +107,7 @@ use de::{
 /// #     Ok(())
 /// # }
 /// ```
-#[derive(Copy, Clone, Debug, Default)]
+#[derive(Copy, Clone, Debug, Default, PartialEq)]
 pub struct IgnoredAny;
 
 impl<'de> Visitor<'de> for IgnoredAny {

serde/src/de/impls.rs

@@ -681,8 +681,8 @@ impl<'de> Visitor<'de> for CStringVisitor {
     where
         A: SeqAccess<'de>,
     {
-        let len = size_hint::cautious(seq.size_hint());
-        let mut values = Vec::with_capacity(len);
+        let capacity = size_hint::cautious::<u8>(seq.size_hint());
+        let mut values = Vec::<u8>::with_capacity(capacity);
 
         while let Some(value) = try!(seq.next_element()) {
             values.push(value);
@@ -936,7 +936,7 @@ macro_rules! seq_impl {
                         A: SeqAccess<'de>,
                     {
                         $clear(&mut self.0);
-                        $reserve(&mut self.0, size_hint::cautious($access.size_hint()));
+                        $reserve(&mut self.0, size_hint::cautious::<T>($access.size_hint()));
 
                         // FIXME: try to overwrite old values here? (Vec, VecDeque, LinkedList)
                         while let Some(value) = try!($access.next_element()) {
@@ -962,7 +962,7 @@ seq_impl!(
     BinaryHeap<T: Ord>,
     seq,
     BinaryHeap::clear,
-    BinaryHeap::with_capacity(size_hint::cautious(seq.size_hint())),
+    BinaryHeap::with_capacity(size_hint::cautious::<T>(seq.size_hint())),
     BinaryHeap::reserve,
     BinaryHeap::push
 );
@@ -992,7 +992,7 @@ seq_impl!(
     HashSet<T: Eq + Hash, S: BuildHasher + Default>,
     seq,
     HashSet::clear,
-    HashSet::with_capacity_and_hasher(size_hint::cautious(seq.size_hint()), S::default()),
+    HashSet::with_capacity_and_hasher(size_hint::cautious::<T>(seq.size_hint()), S::default()),
     HashSet::reserve,
     HashSet::insert
 );
@@ -1002,7 +1002,7 @@ seq_impl!(
     VecDeque<T>,
     seq,
     VecDeque::clear,
-    VecDeque::with_capacity(size_hint::cautious(seq.size_hint())),
+    VecDeque::with_capacity(size_hint::cautious::<T>(seq.size_hint())),
     VecDeque::reserve,
     VecDeque::push_back
 );
@@ -1036,7 +1036,8 @@ where
             where
                 A: SeqAccess<'de>,
             {
-                let mut values = Vec::with_capacity(size_hint::cautious(seq.size_hint()));
+                let capacity = size_hint::cautious::<T>(seq.size_hint());
+                let mut values = Vec::<T>::with_capacity(capacity);
 
                 while let Some(value) = try!(seq.next_element()) {
                     values.push(value);
@@ -1072,7 +1073,7 @@ where
             where
                 A: SeqAccess<'de>,
             {
-                let hint = size_hint::cautious(seq.size_hint());
+                let hint = size_hint::cautious::<T>(seq.size_hint());
                 if let Some(additional) = hint.checked_sub(self.0.len()) {
                     self.0.reserve(additional);
                 }
@@ -1416,7 +1417,7 @@ map_impl!(BTreeMap<K: Ord, V>, map, BTreeMap::new());
 map_impl!(
     HashMap<K: Eq + Hash, V, S: BuildHasher + Default>,
     map,
-    HashMap::with_capacity_and_hasher(size_hint::cautious(map.size_hint()), S::default())
+    HashMap::with_capacity_and_hasher(size_hint::cautious::<(K, V)>(map.size_hint()), S::default())
 );
 
 ////////////////////////////////////////////////////////////////////////////////

serde/src/lib.rs

@@ -93,7 +93,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 // Serde types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/serde/1.0.167")]
+#![doc(html_root_url = "https://docs.rs/serde/1.0.168")]
 // Support using Serde without the standard library!
 #![cfg_attr(not(feature = "std"), no_std)]
 // Unstable functionality only if the user asks for it. For tracking and

serde/src/private/de.rs

@@ -474,7 +474,8 @@ mod content {
         where
             V: SeqAccess<'de>,
         {
-            let mut vec = Vec::with_capacity(size_hint::cautious(visitor.size_hint()));
+            let mut vec =
+                Vec::<Content>::with_capacity(size_hint::cautious::<Content>(visitor.size_hint()));
             while let Some(e) = try!(visitor.next_element()) {
                 vec.push(e);
             }
@@ -485,7 +486,10 @@ mod content {
         where
             V: MapAccess<'de>,
         {
-            let mut vec = Vec::with_capacity(size_hint::cautious(visitor.size_hint()));
+            let mut vec =
+                Vec::<(Content, Content)>::with_capacity(
+                    size_hint::cautious::<(Content, Content)>(visitor.size_hint()),
+                );
             while let Some(kv) = try!(visitor.next_entry()) {
                 vec.push(kv);
             }
@@ -844,7 +848,10 @@ mod content {
             M: MapAccess<'de>,
         {
             let mut tag = None;
-            let mut vec = Vec::with_capacity(size_hint::cautious(map.size_hint()));
+            let mut vec = Vec::<(Content, Content)>::with_capacity(size_hint::cautious::<(
+                Content,
+                Content,
+            )>(map.size_hint()));
             while let Some(k) = try!(map.next_key_seed(TagOrContentVisitor::new(self.tag_name))) {
                 match k {
                     TagOrContent::Tag => {
@@ -2794,6 +2801,13 @@ where
         visitor.visit_unit()
     }
 
+    fn deserialize_ignored_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
+    where
+        V: Visitor<'de>,
+    {
+        visitor.visit_unit()
+    }
+
     forward_to_deserialize_other! {
         deserialize_bool()
         deserialize_i8()
@@ -2816,7 +2830,6 @@ where
         deserialize_tuple(usize)
         deserialize_tuple_struct(&'static str, usize)
         deserialize_identifier()
-        deserialize_ignored_any()
     }
 }
 

serde/src/private/size_hint.rs

@@ -8,9 +8,17 @@ where
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
-#[inline]
-pub fn cautious(hint: Option<usize>) -> usize {
-    cmp::min(hint.unwrap_or(0), 4096)
+pub fn cautious<Element>(hint: Option<usize>) -> usize {
+    const MAX_PREALLOC_BYTES: usize = 1024 * 1024;
+
+    if mem::size_of::<Element>() == 0 {
+        0
+    } else {
+        cmp::min(
+            hint.unwrap_or(0),
+            MAX_PREALLOC_BYTES / mem::size_of::<Element>(),
+        )
+    }
 }
 
 fn helper(bounds: (usize, Option<usize>)) -> Option<usize> {

serde_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_derive"
-version = "1.0.167" # remember to update html_root_url
+version = "1.0.168" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 categories = ["no-std", "no-std::no-alloc"]
 description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"

serde_derive/src/lib.rs

@@ -13,7 +13,7 @@
 //!
 //! [https://serde.rs/derive.html]: https://serde.rs/derive.html
 
-#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.167")]
+#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.168")]
 #![allow(unknown_lints, bare_trait_objects)]
 // Ignored clippy lints
 #![allow(

serde_test/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_test"
-version = "1.0.167" # remember to update html_root_url
+version = "1.0.168" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 build = "build.rs"
 categories = ["development-tools::testing"]

serde_test/src/lib.rs

@@ -144,7 +144,7 @@
 //! # }
 //! ```
 
-#![doc(html_root_url = "https://docs.rs/serde_test/1.0.167")]
+#![doc(html_root_url = "https://docs.rs/serde_test/1.0.168")]
 #![cfg_attr(feature = "cargo-clippy", allow(renamed_and_removed_lints))]
 // Ignored clippy lints
 #![cfg_attr(feature = "cargo-clippy", allow(float_cmp, needless_doctest_main))]

test_suite/tests/test_annotations.rs

@@ -10,7 +10,7 @@
     clippy::uninlined_format_args,
 )]
 
-use serde::de::{self, MapAccess, Unexpected, Visitor};
+use serde::de::{self, IgnoredAny, MapAccess, Unexpected, Visitor};
 use serde::{Deserialize, Deserializer, Serialize, Serializer};
 
 use std::collections::{BTreeMap, HashMap};
@@ -2697,6 +2697,31 @@ fn test_flatten_option() {
     );
 }
 
+#[test]
+fn test_flatten_ignored_any() {
+    #[derive(Deserialize, PartialEq, Debug)]
+    struct Outer {
+        #[serde(flatten)]
+        inner: IgnoredAny,
+    }
+
+    assert_de_tokens(
+        &Outer { inner: IgnoredAny },
+        &[Token::Map { len: None }, Token::MapEnd],
+    );
+
+    assert_de_tokens(
+        &Outer { inner: IgnoredAny },
+        &[
+            Token::Struct {
+                name: "DoNotMatter",
+                len: 0,
+            },
+            Token::StructEnd,
+        ],
+    );
+}
+
 #[test]
 fn test_transparent_struct() {
     #[derive(Serialize, Deserialize, PartialEq, Debug)]