serde_with v3.0.0

This breaking release should not impact most users.
It only affects custom character sets used for base64 of which there are no instances of on GitHub.

Changed

• Upgrade base64 to v0.21 (#543)
  Thanks to @jeff-hiner for submitting the PR.

  Remove support for custom character sets.
  This is technically a breaking change.
  A code search on GitHub revealed no instances of anyone using that, and serde_with ships with many predefined character sets.
  The removal means that future base64 upgrade will no longer be breaking changes.

serde_with v2.3.3

Changed

• Update syn to v2 and darling to v0.20 (#578)
  Update proc-macro dependencies.
  This change should have no impact on users, but now uses the same dependency as serde_derive.

serde_with v2.3.2

Changed

• Improve the error message when deserializing OneOrMany or PickFirst fails.
  It now includes the original error message for each of the individual variants.
  This is possible by dropping untagged enums as the internal implementations, since they will likely never support this, as these old PRs show serde#2376 and serde#1544.

  The new errors look like:

  OneOrMany could not deserialize any variant:
    One: invalid type: map, expected u32
    Many: invalid type: map, expected a sequence
  

  PickFirst could not deserialize any variant:
    First: invalid type: string "Abc", expected u32
    Second: invalid digit found in string
  

Fixed

• Specify the correct minimum serde version as dependency. (#588)
  Thanks to @nox for submitting a PR.

serde_with v2.3.1

Fixed

• Undo the changes to the trait bound for Seq. (#570, #571)
  The new implementation caused issues with serialization formats that require the sequence length beforehand.
  It also caused problems, that certain attributes which worked before no longer worked, due to mismatching number of references.

  Thanks to @stefunctional for reporting and for @stephaneyfx for providing a test case.

serde_with v2.3.0

Added

• Add serde_as compatible versions for the existing duplicate key and value handling. (#534)
  The new types MapPreventDuplicates, MapFirstKeyWins, SetPreventDuplicates, and SetLastValueWins can replace the existing modules maps_duplicate_key_is_error, maps_first_key_wins, sets_duplicate_value_is_error, and sets_last_value_wins.

• Added a new KeyValueMap type using the map key as a struct field. (#341)
  This conversion is useful for maps, where an ID value is the map key, but the ID should become part of a single struct.
  The conversion allows this, by using a special field named $key$.

  This conversion is possible for structs and maps, using the $key$ field.
  Tuples, tuple structs, and sequences are supported by turning the first value into the map key.

  Each of the SimpleStructs

  // Somewhere there is a collection:
  // #[serde_as(as = "KeyValueMap<_>")]
  // Vec<SimpleStruct>,
  
  #[derive(Serialize, Deserialize)]
  struct SimpleStruct {
      b: bool,
      // The field named `$key$` will become the map key
      #[serde(rename = "$key$")]
      id: String,
      i: i32,
  }

  will turn into a JSON snippet like this.

  "id-0000": {
    "b": false,
    "i": 123
  },

Changed

• Relax the trait bounds of Seq to allow for more custom types. (#565)
  This extends the support beyond tuples.

Fixed

• EnumMap passes the human_readable status of the Serializer to more places.
• Support alloc on targets without target_has_atomic = "ptr". (#560)
  Thanks to @vembacher for reporting and fixing the issue.

serde_with v2.2.0

Added

• Add new Map and Seq types for converting between maps and tuple lists. (#527)

  The behavior is not new, but already present using BTreeMap/HashMap or Vec.
  However, the new types Map and Seq are also available on no_std, even without the alloc feature.

Changed

• Pin the serde_with_macros dependency to the same version as the main crate.
  This simplifies publishing and ensures that always a compatible version is picked.

Fixed

• serde_with::apply had an issue matching types when invisible token groups where in use (#538)
  The token groups can stem from macro_rules expansion, but should be treated mostly transparent.
  The old code required a group to match a group, while now groups are silently removed when checking for type patterns.

serde_with v2.1.0

Added

• Add new apply attribute to simplify repetitive attributes over many fields.
  Multiple rules and multiple attributes can be provided each.

  #[serde_with::apply(
      Option => #[serde(default)] #[serde(skip_serializing_if = "Option::is_none")],
      Option<bool> => #[serde(rename = "bool")],
  )]
  #[derive(serde::Serialize)]
  struct Data {
      a: Option<String>,
      b: Option<u64>,
      c: Option<String>,
      d: Option<bool>,
  }

  The apply attribute will expand into this, applying the attributs to the matching fields:

  #[derive(serde::Serialize)]
  struct Data {
      #[serde(default)]
      #[serde(skip_serializing_if = "Option::is_none")]
      a: Option<String>,
      #[serde(default)]
      #[serde(skip_serializing_if = "Option::is_none")]
      b: Option<u64>,
      #[serde(default)]
      #[serde(skip_serializing_if = "Option::is_none")]
      c: Option<String>,
      #[serde(default)]
      #[serde(skip_serializing_if = "Option::is_none")]
      #[serde(rename = "bool")]
      d: Option<bool>,
  }

  The attribute supports field matching using many rules, such as _ to apply to all fields and partial generics like Option to match any Option be it Option<String>, Option<bool>, or Option<T>.

Fixed

• The derive macros SerializeDisplay and DeserializeFromStr now take better care not to use conflicting names for generic values. (#526)
  All used generics now start with __ to make conflicts with manually written code unlikely.

  Thanks to @Elrendio for submitting a PR fixing the issue.

serde_with_macros v2.1.0

Added

• Add new apply attribute to simplify repetitive attributes over many fields.
  Multiple rules and multiple attributes can be provided each.

  #[serde_with::apply(
      Option => #[serde(default)] #[serde(skip_serializing_if = "Option::is_none")],
      Option<bool> => #[serde(rename = "bool")],
  )]
  #[derive(serde::Serialize)]
  struct Data {
      a: Option<String>,
      b: Option<u64>,
      c: Option<String>,
      d: Option<bool>,
  }

  The apply attribute will expand into this, applying the attributs to the matching fields:

  #[derive(serde::Serialize)]
  struct Data {
      #[serde(default)]
      #[serde(skip_serializing_if = "Option::is_none")]
      a: Option<String>,
      #[serde(default)]
      #[serde(skip_serializing_if = "Option::is_none")]
      b: Option<u64>,
      #[serde(default)]
      #[serde(skip_serializing_if = "Option::is_none")]
      c: Option<String>,
      #[serde(default)]
      #[serde(skip_serializing_if = "Option::is_none")]
      #[serde(rename = "bool")]
      d: Option<bool>,
  }

  The attribute supports field matching using many rules, such as _ to apply to all fields and partial generics like Option to match any Option be it Option<String>, Option<bool>, or Option<T>.

Fixed

• The derive macros SerializeDisplay and DeserializeFromStr now take better care not to use conflicting names for generic values. (#526)
  All used generics now start with __ to make conflicts with manually written code unlikely.

  Thanks to @Elrendio for submitting a PR fixing the issue.

serde_with v2.0.1

Added

• time added support for the well-known Iso8601 format.
  This extends the existing support of Rfc2822 and Rfc3339.

Changed

• Warn if serde_as is used on an enum variant.
  Attributes on enum variants were never supported.
  But #[serde(with = "...")] can be added on variants, such that some confusion can occur when migration (#499).

Note

A cargo bug (cargo#10801) means that upgrading from v1 to v2 may add unnecessary crates to the Cargo.lock file.
A diff of the lock-file makes it seem that serde_with depends on new crates, even though these crates are unused and will not get compiled or linked.
However, tools consuming Cargo.lock or cargo metadata might give wrong results.

serde_with_macros v2.0.1

Changed

• Warn if serde_as is used on an enum variant.
  Attributes on enum variants were never supported.
  But #[serde(with = "...")] can be added on variants, such that some confusion can occur when migration (#499).