Add postcard as a Serde format

.github/workflows/ci.yml

@@ -104,7 +104,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        serde_format: [bincode, cbor, cbor4ii]
+        serde_format: [bincode, cbor, cbor4ii, postcard]
         toolchain: [stable, nightly]
         self_ty_in_mod_name: [false, true]
 

README.md

@@ -411,6 +411,8 @@ The `test-fuzz` package currently supports the following features:
 
 - `serde_cbor4ii` - [CBOR 0x(4+4)9 0x49]
 
+- `serde_postcard` - [Postcard]
+
 ## Auto-generated corpus files
 
 `cargo-test-fuzz` can auto-generate values for types that implement certain traits. If all of a target's argument types implement such traits, `cargo-test-fuzz` can auto-generate corpus files for the target.
@@ -498,6 +500,7 @@ These options are incompatible in the following sense. If a fuzz target's argume
 [Limitations]: #limitations
 [Macros and Inline Functions Exception]: https://spdx.org/licenses/mif-exception.html
 [Overview]: #overview
+[Postcard]: https://github.com/jamesmunns/postcard
 [Serde CBOR]: https://github.com/pyfisch/cbor
 [Serde attributes]: https://serde.rs/attributes.html
 [Substrate externalities]: https://substrate.dev/docs/en/knowledgebase/runtime/tests#mock-runtime-storage

internal/Cargo.toml

@@ -20,12 +20,14 @@ serde = "1.0"
 
 bincode = "1.3"
 cbor4ii = { version = "0.3", features = ["serde1", "use_std"], optional = true }
+postcard = { version = "1.0", features = ["use-std"], optional = true }
 serde_cbor = { version = "0.11", optional = true }
 
 [features]
 __serde_bincode = []
 __serde_cbor = ["serde_cbor"]
 __serde_cbor4ii = ["cbor4ii"]
+__serde_postcard = ["postcard"]
 
 [lints]
 workspace = true

internal/build.rs

@@ -2,7 +2,8 @@ fn main() {
     #[cfg(not(any(
         feature = "__serde_bincode",
         feature = "__serde_cbor",
-        feature = "__serde_cbor4ii"
+        feature = "__serde_cbor4ii",
+        feature = "__postcard"
     )))]
     println!("cargo:rustc-cfg=serde_default");
 }

internal/src/serde_format.rs

@@ -18,6 +18,9 @@ pub fn as_feature() -> &'static str {
     #[cfg(feature = "__serde_cbor4ii")]
     formats.push("serde_cbor4ii");
 
+    #[cfg(feature = "__serde_postcard")]
+    formats.push("serde_postcard");
+
     assert!(
         formats.len() <= 1,
         "{}",
@@ -37,6 +40,9 @@ pub const fn serializes_variant_names() -> bool {
 
     #[cfg(feature = "__serde_cbor4ii")]
     return true;
+
+    #[cfg(feature = "__serde_postcard")]
+    return false;
 }
 
 pub fn serialize<T: Serialize>(args: &T) -> Vec<u8> {
@@ -64,6 +70,9 @@ pub fn serialize<T: Serialize>(args: &T) -> Vec<u8> {
         cbor4ii::serde::to_writer(&mut data, args).unwrap();
         data
     };
+
+    #[cfg(feature = "__serde_postcard")]
+    return postcard::to_io(args);
 }
 
 pub fn deserialize<T: DeserializeOwned, R: Read>(reader: R) -> Option<T> {
@@ -84,4 +93,7 @@ pub fn deserialize<T: DeserializeOwned, R: Read>(reader: R) -> Option<T> {
         let reader = std::io::BufReader::new(reader);
         cbor4ii::serde::from_reader(reader).ok()
     };
+
+    #[cfg(feature = "__serde_postcard")]
+    return postcard::from_io(reader).ok();
 }

test-fuzz/Cargo.toml

@@ -38,6 +38,7 @@ self_ty_in_mod_name = ["test-fuzz-macro/__self_ty_in_mod_name"]
 serde_bincode = ["internal/__serde_bincode"]
 serde_cbor = ["internal/__serde_cbor"]
 serde_cbor4ii = ["internal/__serde_cbor4ii"]
+serde_postcard = ["internal/__serde_postcard"]
 __persistent = ["afl", "test-fuzz-macro/__persistent"]
 
 [lints]

test-fuzz/build.rs

@@ -2,7 +2,8 @@ fn main() {
     #[cfg(not(any(
         feature = "serde_bincode",
         feature = "serde_cbor",
-        feature = "serde_cbor4ii"
+        feature = "serde_cbor4ii",
+        feature = "serde_postcard"
     )))]
     println!("cargo:rustc-cfg=serde_default");
 }