deprecate lib arg on contracttype/error

Author: leighmcculloch

soroban-sdk-macros/src/lib.rs

@@ -81,6 +81,24 @@ pub(crate) fn export_arg_v2_deprecation(export: &Option<bool>, ident: &syn::Iden
     }
 }
 
+/// Emit a deprecation warning when `lib` is set on a contract type or error.
+/// The argument is a vestige of an earlier design that was never used and will
+/// be removed in a future release.
+pub(crate) fn lib_arg_deprecation(lib: &Option<String>, ident: &syn::Ident) -> TokenStream2 {
+    if lib.is_some() {
+        let marker = format_ident!("__SOROBAN_LIB_ARG_DEPRECATED_FOR_{}", ident);
+        quote! {
+            #[doc(hidden)]
+            #[allow(non_upper_case_globals)]
+            #[deprecated = "`lib` is deprecated and will be removed in a future release"]
+            const #marker: () = ();
+            const _: () = #marker;
+        }
+    } else {
+        TokenStream2::new()
+    }
+}
+
 #[proc_macro]
 pub fn internal_symbol_short(input: TokenStream) -> TokenStream {
     let input = parse_macro_input!(input as LitStr);
@@ -456,6 +474,7 @@ pub fn contracttype(metadata: TokenStream, input: TokenStream) -> TokenStream {
         Err(e) => return e.to_compile_error().into(),
     }
     let export_deprecation = export_arg_v2_deprecation(&args.export, ident);
+    let lib_deprecation = lib_arg_deprecation(&args.lib, ident);
     // Under `experimental_spec_shaking_v2` the spec is always emitted and
     // reachability determines what is retained, so the `export` argument is
     // ignored (a deprecation warning is emitted above). Otherwise, honor an
@@ -512,6 +531,7 @@ pub fn contracttype(metadata: TokenStream, input: TokenStream) -> TokenStream {
     quote! {
         #input
         #export_deprecation
+        #lib_deprecation
         #derived
     }
     .into()
@@ -533,6 +553,7 @@ pub fn contracterror(metadata: TokenStream, input: TokenStream) -> TokenStream {
     let ident = &input.ident;
     let attrs = &input.attrs;
     let export_deprecation = export_arg_v2_deprecation(&args.export, ident);
+    let lib_deprecation = lib_arg_deprecation(&args.lib, ident);
     // Under `experimental_spec_shaking_v2` the spec is always emitted and
     // reachability determines what is retained, so the `export` argument is
     // ignored (a deprecation warning is emitted above). Otherwise, honor an
@@ -567,6 +588,7 @@ pub fn contracterror(metadata: TokenStream, input: TokenStream) -> TokenStream {
     quote! {
         #input
         #export_deprecation
+        #lib_deprecation
         #derived
     }
     .into()

soroban-sdk/tests/compile_fails.rs

@@ -2,4 +2,5 @@
 fn compile_fails() {
     let t = trybuild::TestCases::new();
     t.compile_fail("tests/compile_fails/contracttrait_cfg_errors.rs");
+    t.compile_fail("tests/compile_fails/contracttype_lib_deprecated.rs");
 }

soroban-sdk/tests/compile_fails/contracttype_lib_deprecated.rs

@@ -0,0 +1,20 @@
+// Setting `lib` on `contracttype` or `contracterror` is deprecated. With the
+// `deprecated` lint denied, using it must fail to compile, proving the
+// deprecation warning is emitted.
+#![deny(deprecated)]
+
+use soroban_sdk::{contracterror, contracttype};
+
+#[contracttype(lib = "libname")]
+pub struct S {
+    pub a: u32,
+}
+
+#[contracterror(lib = "libname")]
+#[derive(Copy, Clone)]
+#[repr(u32)]
+pub enum E {
+    A = 1,
+}
+
+fn main() {}

soroban-sdk/tests/compile_fails/contracttype_lib_deprecated.stderr

@@ -0,0 +1,17 @@
+error: use of deprecated constant `__SOROBAN_LIB_ARG_DEPRECATED_FOR_S`: `lib` is deprecated and will be removed in a future release
+ --> tests/compile_fails/contracttype_lib_deprecated.rs:9:12
+  |
+9 | pub struct S {
+  |            ^
+  |
+note: the lint level is defined here
+ --> tests/compile_fails/contracttype_lib_deprecated.rs:4:9
+  |
+4 | #![deny(deprecated)]
+  |         ^^^^^^^^^^
+
+error: use of deprecated constant `__SOROBAN_LIB_ARG_DEPRECATED_FOR_E`: `lib` is deprecated and will be removed in a future release
+  --> tests/compile_fails/contracttype_lib_deprecated.rs:16:10
+   |
+16 | pub enum E {
+   |          ^