MAINT-5011: Try to enrich catch (...) logging throughout viewer.

Turns out we have a surprising number of catch (...) clauses in the viewer
code base. If all we currently do is

    LL_ERRS() << "unknown exception" << LL_ENDL;

then call CRASH_ON_UNHANDLED_EXCEPTION() instead. If what we do is

    LL_WARNS() << "unknown exception" << LL_ENDL;

then call LOG_UNHANDLED_EXCEPTION() instead.

Since many places need LOG_UNHANDLED_EXCEPTION() and nobody catches
LLContinueError yet, eliminate LLContinueError& parameter from
LOG_UNHANDLED_EXCEPTION(). This permits us to use the same log message as
CRASH_ON_UNHANDLED_EXCEPTION(), just with a different severity level.

Where a catch (...) clause actually provides contextual information, or makes
an error string, add boost::current_exception_diagnostic_information() to try
to figure out actual exception class and message.

2 files changed, 23 insertions, 15 deletions

diff --git a/indra/llcommon/llexception.cpp b/indra/llcommon/llexception.cpp
index f48509b2aa..9a6dfee3f1 100644
--- a/indra/llcommon/llexception.cpp
+++ b/indra/llcommon/llexception.cpp
@@ -21,21 +21,28 @@
 // other Linden headers
 #include "llerror.h"
 
+namespace {
+// used by crash_on_unhandled_exception_() and log_unhandled_exception_()
+void log_unhandled_exception_(LLError::ELevel level,
+                              const char* file, int line, const char* pretty_function)
+{
+    // log same message but allow caller-specified severity level
+    // lllog() is the macro underlying LL_ERRS(), LL_WARNS() et al.
+    lllog(level, false) << file << "(" << line << "): Unhandled exception caught in "
+                        << pretty_function
+                        << ":\n" << boost::current_exception_diagnostic_information() << LL_ENDL;
+}
+}
+
 void crash_on_unhandled_exception_(const char* file, int line, const char* pretty_function)
 {
-    // LL_ERRS() terminates, but also propagates message into crash dump.
-    LL_ERRS() << file << "(" << line << "): Unhandled exception caught in " << pretty_function
-              << ":\n" << boost::current_exception_diagnostic_information() << LL_ENDL;
+    // LL_ERRS() terminates and propagates message into crash dump.
+    log_unhandled_exception_(LLError::LEVEL_ERROR, file, line, pretty_function);
 }
 
-void log_unhandled_exception_(const char* file, int line, const char* pretty_function,
-                             const LLContinueError& e)
+void log_unhandled_exception_(const char* file, int line, const char* pretty_function)
 {
     // Use LL_WARNS() because we seriously do not expect this to happen
-    // routinely, but we DO expect to return from this function. Deriving your
-    // exception from LLContinueError implies that such an exception should
-    // NOT be fatal to the viewer, only to its current task.
-    LL_WARNS() << file << "(" << line << "): Unhandled " << typeid(e).name()
-               << " exception caught in " << pretty_function
-               << ":\n" << boost::current_exception_diagnostic_information() << LL_ENDL;
+    // routinely, but we DO expect to return from this function.
+    log_unhandled_exception_(LLError::LEVEL_WARN, file, line, pretty_function);
 }
diff --git a/indra/llcommon/llexception.h b/indra/llcommon/llexception.h
index e9e25ae689..2a0f5e79eb 100644
--- a/indra/llcommon/llexception.h
+++ b/indra/llcommon/llexception.h
@@ -74,9 +74,10 @@ struct LLContinueError: public LLException
      crash_on_unhandled_exception_(__FILE__, __LINE__, __PRETTY_FUNCTION__)
 void crash_on_unhandled_exception_(const char*, int, const char*);
 
-/// Call this from a catch (const LLContinueError&) clause
-#define LOG_UNHANDLED_EXCEPTION(EXC) \
-     log_unhandled_exception_(__FILE__, __LINE__, __PRETTY_FUNCTION__, EXC)
-void log_unhandled_exception_(const char*, int, const char*, const LLContinueError&);
+/// Call this from a catch (const LLContinueError&) clause, or from a catch
+/// (...) clause in which you do NOT want the viewer to crash.
+#define LOG_UNHANDLED_EXCEPTION() \
+     log_unhandled_exception_(__FILE__, __LINE__, __PRETTY_FUNCTION__)
+void log_unhandled_exception_(const char*, int, const char*);
 
 #endif /* ! defined(LL_LLEXCEPTION_H) */