Less Mutex poisoning

CHANGELOG.md

@@ -10,6 +10,10 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - Raised MSRV to 1.70.0 to remove `lazy_static` dependency
   ([#550](https://github.com/asomers/mockall/pull/550))
 
+- No longer poison a Context object's internal `Mutex` when panicing.  This
+  requires the "nightly" feature.
+  ([#527](https://github.com/asomers/mockall/pull/527))
+
 ## [ 0.12.1 ] - 2023-12-21
 
 ### Fixed

mockall/tests/clear_expectations_on_panic.rs

@@ -34,7 +34,7 @@ fn too_few_calls() {
 
 // We shouldn't panic during drop in this case.  Regression test for
 // https://github.com/asomers/mockall/issues/491
-#[should_panic(expected = "called `Result::unwrap()` on an `Err` value: PoisonError { .. }")]
+#[cfg_attr(not(feature = "nightly"), ignore)]
 #[test]
 fn too_many_calls() {
     panic::catch_unwind(|| {

mockall_derive/src/mock_function.rs

@@ -1574,6 +1574,14 @@ impl<'a> ToTokens for Context<'a> {
         #[cfg(feature = "nightly_derive")]
         let must_use = quote!();
 
+        #[cfg(not(feature = "nightly_derive"))]
+        let clear_poison = quote!();
+        #[cfg(feature = "nightly_derive")]
+        let clear_poison = quote!(
+            #[allow(clippy::incompatible_msrv)]
+            get_expectations().clear_poison();
+        );
+
         quote!(
             /// Manages the context for expectations of static methods.
             ///
@@ -1621,6 +1629,9 @@ impl<'a> ToTokens for Context<'a> {
             impl #ty_ig Drop for Context #ty_tg #ty_wc {
                 fn drop(&mut self) {
                     if ::std::thread::panicking() {
+                        // Clear poison since we're about to clear the Mutex's
+                        // contents anyway.
+                        #clear_poison
                         // Drain all expectations so other tests can run with a
                         // blank slate.  But ignore errors so we don't
                         // double-panic.