Externalize derive macro implementation

.github/workflows/ci.yml

@@ -134,6 +134,7 @@ jobs:
       - run: cargo docs-rs -p serde
       - run: cargo docs-rs -p serde_derive
       - run: cargo docs-rs -p serde_derive_internals
+      - run: cargo docs-rs -p serde_derive_implementation
 
   clippy:
     name: Clippy
@@ -146,6 +147,7 @@ jobs:
       - run: cd serde && cargo clippy --features rc,unstable -- -Dclippy::all -Dclippy::pedantic
       - run: cd serde_derive && cargo clippy -- -Dclippy::all -Dclippy::pedantic
       - run: cd serde_derive_internals && cargo clippy -- -Dclippy::all -Dclippy::pedantic
+      - run: cd serde_derive_implementation && cargo clippy -- -Dclippy::all -Dclippy::pedantic
       - run: cd test_suite && cargo clippy --tests --features unstable -- -Dclippy::all -Dclippy::pedantic
       - run: cd test_suite/no_std && cargo clippy -- -Dclippy::all -Dclippy::pedantic
 

Cargo.toml

@@ -2,6 +2,7 @@
 members = [
     "serde",
     "serde_derive",
+    "serde_derive_implementation",
     "serde_derive_internals",
     "test_suite",
 ]

serde_derive/src/de.rs → serde_derive/src/implementation/de.rs

@@ -1,7 +1,7 @@
-use crate::fragment::{Expr, Fragment, Match, Stmts};
+use crate::implementation::fragment::{Expr, Fragment, Match, Stmts};
+use crate::implementation::{bound, dummy, pretend, this};
 use crate::internals::ast::{Container, Data, Field, Style, Variant};
 use crate::internals::{attr, replace_receiver, ungroup, Ctxt, Derive};
-use crate::{bound, dummy, pretend, this};
 use proc_macro2::{Literal, Span, TokenStream};
 use quote::{quote, quote_spanned, ToTokens};
 use std::collections::BTreeSet;

serde_derive/src/fragment.rs → serde_derive/src/implementation/fragment.rs

@@ -12,13 +12,13 @@ pub enum Fragment {
 
 macro_rules! quote_expr {
     ($($tt:tt)*) => {
-        $crate::fragment::Fragment::Expr(quote!($($tt)*))
+        $crate::implementation::fragment::Fragment::Expr(quote!($($tt)*))
     }
 }
 
 macro_rules! quote_block {
     ($($tt:tt)*) => {
-        $crate::fragment::Fragment::Block(quote!($($tt)*))
+        $crate::implementation::fragment::Fragment::Block(quote!($($tt)*))
     }
 }
 

serde_derive/src/implementation/mod.rs

@@ -0,0 +1,10 @@
+#[macro_use]
+mod bound;
+#[macro_use]
+mod fragment;
+
+pub mod de;
+mod dummy;
+mod pretend;
+pub mod ser;
+mod this;

serde_derive/src/ser.rs → serde_derive/src/implementation/ser.rs

@@ -1,7 +1,7 @@
-use crate::fragment::{Fragment, Match, Stmts};
+use crate::implementation::fragment::{Fragment, Match, Stmts};
+use crate::implementation::{bound, dummy, pretend, this};
 use crate::internals::ast::{Container, Data, Field, Style, Variant};
 use crate::internals::{attr, replace_receiver, Ctxt, Derive};
-use crate::{bound, dummy, pretend, this};
 use proc_macro2::{Span, TokenStream};
 use quote::{quote, quote_spanned};
 use syn::spanned::Spanned;

serde_derive/src/lib.rs

@@ -68,22 +68,14 @@ extern crate syn;
 
 extern crate proc_macro;
 
+mod implementation;
 mod internals;
 
 use proc_macro::TokenStream;
 use syn::parse_macro_input;
 use syn::DeriveInput;
 
-#[macro_use]
-mod bound;
-#[macro_use]
-mod fragment;
-
-mod de;
-mod dummy;
-mod pretend;
-mod ser;
-mod this;
+use implementation::{de, ser};
 
 #[proc_macro_derive(Serialize, attributes(serde))]
 pub fn derive_serialize(input: TokenStream) -> TokenStream {

serde_derive_implementation/Cargo.toml

@@ -0,0 +1,26 @@
+[package]
+name = "serde_derive_implementation"
+version = "0.29.1"
+authors = ["Erick Tryzelaar <[email protected]>", "David Tolnay <[email protected]>"]
+description = "Serde derive macros implementations."
+documentation = "https://docs.rs/serde_derive_implementation"
+edition = "2015"
+exclude = ["build.rs"]
+homepage = "https://serde.rs"
+keywords = ["serde", "serialization"]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/serde-rs/serde"
+rust-version = "1.56"
+
+[lib]
+path = "lib.rs"
+
+[dependencies]
+proc-macro2 = { workspace = true }
+quote = { workspace = true }
+syn = { workspace = true, features = ["clone-impls", "derive", "parsing", "printing"] }
+serde_derive_internals = { path = "../serde_derive_internals" }
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]
+rustdoc-args = ["--generate-link-to-definition"]

serde_derive_implementation/LICENSE-APACHE

@@ -0,0 +1 @@
+../LICENSE-APACHE

serde_derive_implementation/LICENSE-MIT

@@ -0,0 +1 @@
+../LICENSE-MIT

serde_derive_implementation/build.rs

@@ -0,0 +1,23 @@
+use std::path::Path;
+
+fn main() {
+    // Warning: build.rs is not published to crates.io.
+
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-changed=src/mod.rs");
+
+    println!("cargo:rustc-cfg=check_cfg");
+    println!("cargo:rustc-check-cfg=cfg(check_cfg)");
+    println!("cargo:rustc-check-cfg=cfg(exhaustive)");
+    println!("cargo:rustc-check-cfg=cfg(serde_build_from_git)");
+    println!("cargo:rustc-check-cfg=cfg(feature, values(\"deserialize_in_place\"))");
+
+    // Sometimes on Windows the git checkout does not correctly wire up the
+    // symlink from serde_derive_implementation/src to serde_derive/src/internals.
+    // When this happens we'll just build based on relative paths within the git
+    // repo.
+    let mod_behind_symlink = Path::new("src/mod.rs");
+    if !mod_behind_symlink.exists() {
+        println!("cargo:rustc-cfg=serde_build_from_git");
+    }
+}

serde_derive_implementation/lib.rs

@@ -0,0 +1,53 @@
+#![doc(html_root_url = "https://docs.rs/serde_derive_impl/0.29.1")]
+#![cfg_attr(not(check_cfg), allow(unexpected_cfgs))]
+// Ignored clippy lints
+#![allow(
+    clippy::cognitive_complexity,
+    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/7575
+    clippy::collapsible_match,
+    clippy::derive_partial_eq_without_eq,
+    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/6797
+    clippy::manual_map,
+    clippy::missing_panics_doc,
+    clippy::redundant_field_names,
+    clippy::result_unit_err,
+    clippy::should_implement_trait,
+    clippy::trivially_copy_pass_by_ref,
+    clippy::wildcard_in_or_patterns,
+    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/5704
+    clippy::unnested_or_patterns,
+)]
+// Ignored clippy_pedantic lints
+#![allow(
+    clippy::doc_markdown,
+    clippy::enum_glob_use,
+    clippy::items_after_statements,
+    clippy::let_underscore_untyped,
+    clippy::manual_assert,
+    clippy::match_same_arms,
+    // clippy bug: https://github.com/rust-lang/rust-clippy/issues/6984
+    clippy::match_wildcard_for_single_variants,
+    clippy::missing_errors_doc,
+    clippy::module_name_repetitions,
+    clippy::must_use_candidate,
+    clippy::return_self_not_must_use,
+    clippy::similar_names,
+    clippy::single_match_else,
+    clippy::struct_excessive_bools,
+    clippy::too_many_lines,
+    clippy::unused_self,
+    clippy::wildcard_imports
+)]
+
+extern crate proc_macro2;
+extern crate quote;
+extern crate syn;
+extern crate serde_derive_internals;
+
+use serde_derive_internals as internals;
+
+#[cfg_attr(serde_build_from_git, path = "../serde_derive/src/implementation/mod.rs")]
+#[cfg_attr(not(serde_build_from_git), path = "src/mod.rs")]
+mod implementation;
+
+pub use implementation::*;

serde_derive_implementation/src

@@ -0,0 +1 @@
+../serde_derive/src/implementation/