Workaround for RUSTDOCFLAGS='--cfg=docsrs'

Author: dtolnay

serde/build.rs

@@ -19,9 +19,7 @@ use serde_core::__private$$ as serde_core_private;
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
 
-    if env::var_os("DOCS_RS").is_some() {
-        println!("cargo:rustc-cfg=no_serde_core");
-    }
+    println!("cargo:rustc-cfg=if_docsrs_then_no_serde_core");
 
     let out_dir = PathBuf::from(env::var_os("OUT_DIR").unwrap());
     let patch_version = env::var("CARGO_PKG_VERSION_PATCH").unwrap();
@@ -35,12 +33,12 @@ fn main() {
 
     if minor >= 77 {
         println!("cargo:rustc-check-cfg=cfg(feature, values(\"result\"))");
+        println!("cargo:rustc-check-cfg=cfg(if_docsrs_then_no_serde_core)");
         println!("cargo:rustc-check-cfg=cfg(no_core_cstr)");
         println!("cargo:rustc-check-cfg=cfg(no_core_error)");
         println!("cargo:rustc-check-cfg=cfg(no_core_net)");
         println!("cargo:rustc-check-cfg=cfg(no_core_num_saturating)");
         println!("cargo:rustc-check-cfg=cfg(no_diagnostic_namespace)");
-        println!("cargo:rustc-check-cfg=cfg(no_serde_core)");
         println!("cargo:rustc-check-cfg=cfg(no_serde_derive)");
         println!("cargo:rustc-check-cfg=cfg(no_std_atomic)");
         println!("cargo:rustc-check-cfg=cfg(no_std_atomic64)");

serde_core/build.rs

@@ -29,12 +29,12 @@ fn main() {
     };
 
     if minor >= 77 {
+        println!("cargo:rustc-check-cfg=cfg(if_docsrs_then_no_serde_core)");
         println!("cargo:rustc-check-cfg=cfg(no_core_cstr)");
         println!("cargo:rustc-check-cfg=cfg(no_core_error)");
         println!("cargo:rustc-check-cfg=cfg(no_core_net)");
         println!("cargo:rustc-check-cfg=cfg(no_core_num_saturating)");
         println!("cargo:rustc-check-cfg=cfg(no_diagnostic_namespace)");
-        println!("cargo:rustc-check-cfg=cfg(no_serde_core)");
         println!("cargo:rustc-check-cfg=cfg(no_serde_derive)");
         println!("cargo:rustc-check-cfg=cfg(no_std_atomic)");
         println!("cargo:rustc-check-cfg=cfg(no_std_atomic64)");

serde_core/src/crate_root.rs

@@ -132,12 +132,12 @@ macro_rules! crate_root {
             };
         }
 
-        #[cfg_attr(no_serde_core, path = "core/de/mod.rs")]
+        #[cfg_attr(all(docsrs, if_docsrs_then_no_serde_core), path = "core/de/mod.rs")]
         pub mod de;
-        #[cfg_attr(no_serde_core, path = "core/ser/mod.rs")]
+        #[cfg_attr(all(docsrs, if_docsrs_then_no_serde_core), path = "core/ser/mod.rs")]
         pub mod ser;
 
-        #[cfg_attr(no_serde_core, path = "core/format.rs")]
+        #[cfg_attr(all(docsrs, if_docsrs_then_no_serde_core), path = "core/format.rs")]
         mod format;
 
         #[doc(inline)]
@@ -147,7 +147,10 @@ macro_rules! crate_root {
 
         // Used by generated code. Not public API.
         #[doc(hidden)]
-        #[cfg_attr(no_serde_core, path = "core/private/mod.rs")]
+        #[cfg_attr(
+            all(docsrs, if_docsrs_then_no_serde_core),
+            path = "core/private/mod.rs"
+        )]
         mod private;
 
         // Used by declarative macro generated code. Not public API.
@@ -162,7 +165,7 @@ macro_rules! crate_root {
         include!(concat!(env!("OUT_DIR"), "/private.rs"));
 
         #[cfg(all(not(feature = "std"), no_core_error))]
-        #[cfg_attr(no_serde_core, path = "core/std_error.rs")]
+        #[cfg_attr(all(docsrs, if_docsrs_then_no_serde_core), path = "core/std_error.rs")]
         mod std_error;
     };
 }