1 files changed, 25 insertions, 7 deletions

diff --git a/indra/llcommon/tests/wrapllerrs.h b/indra/llcommon/tests/wrapllerrs.h
index 3fb79f6b5d..b07d5afbd8 100644
--- a/indra/llcommon/tests/wrapllerrs.h
+++ b/indra/llcommon/tests/wrapllerrs.h
@@ -82,18 +82,36 @@ struct WrapLLErrs
         LLTHROW(FatalException(message));
     }
 
+    /// Convenience wrapper for catch_what<FatalException>()
+    //
+    // The implementation makes it clear that this function need not be a
+    // member; it could easily be a free function. It is a member because it
+    // makes no sense to attempt to catch FatalException unless there is a
+    // WrapLLErrs instance in scope. Without a live WrapLLErrs instance, any
+    // LL_ERRS() reached by code within 'func' would terminate the test
+    // program instead of throwing FatalException.
+    //
+    // We were tempted to introduce a free function, likewise accepting
+    // arbitrary 'func', that would instantiate WrapLLErrs and then call
+    // catch_llerrs() on that instance. We decided against it, for this
+    // reason: on extending a test function containing a single call to that
+    // free function, a maintainer would most likely make additional calls to
+    // that free function, instead of switching to an explicit WrapLLErrs
+    // declaration with several calls to its catch_llerrs() member function.
+    // Even a construct such as WrapLLErrs().catch_llerrs(...) would make the
+    // object declaration more visible; it's not unreasonable to expect a
+    // maintainer to extend that by naming and reusing the WrapLLErrs instance.
+    template <typename FUNC>
+    std::string catch_llerrs(FUNC func)
+    {
+        return catch_what<FatalException>(func);
+    }
+
     std::string error;
     LLError::SettingsStoragePtr mPriorErrorSettings;
     LLError::FatalFunction mPriorFatal;
 };
 
-/// Convenience wrapper for catch_what<WrapLLErrs::FatalException>()
-template <typename FUNC>
-std::string catch_llerrs(FUNC func)
-{
-    return catch_what<WrapLLErrs::FatalException>(func);
-}
-
 /**
  * Capture log messages. This is adapted (simplified) from the one in
  * llerror_test.cpp.