From 030035bd25b3ededb2f78be1f576f2fe0e7d9c90 Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Tue, 23 Oct 2018 09:52:46 +0200
Subject: Move invalid_argument handler from default_thunk() to call()

This way we let a custom thunk catch derived exception (like invalid_path).
---
 build2/function.cxx | 26 ++++++++++++++------------
 build2/function.hxx | 10 +++++-----
 2 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/build2/function.cxx b/build2/function.cxx
index 44bda57..47d4733 100644
--- a/build2/function.cxx
+++ b/build2/function.cxx
@@ -238,7 +238,20 @@ namespace build2
           }
         }
 
-        return make_pair (f->impl (base, move (args), *f), true);
+        try
+        {
+          return make_pair (f->impl (base, move (args), *f), true);
+        }
+        catch (const invalid_argument& e)
+        {
+          diag_record dr (fail);
+          dr << "invalid argument";
+
+          if (*e.what () != '\0')
+            dr << ": " << e;
+
+          dr << endf;
+        }
       }
     case 0:
       {
@@ -298,7 +311,6 @@ namespace build2
   default_thunk (const scope* base,
                  vector_view<value> args,
                  const function_overload& f)
-  try
   {
     // Call the cast thunk.
     //
@@ -310,16 +322,6 @@ namespace build2
     auto d (reinterpret_cast<const cast_data*> (&f.data));
     return d->thunk (base, move (args), d);
   }
-  catch (const invalid_argument& e)
-  {
-    diag_record dr (fail);
-    dr << "invalid argument";
-
-    if (*e.what () != '\0')
-      dr << ": " << e;
-
-    dr << endf;
-  }
 
 #if !defined(_MSC_VER) || _MSC_VER > 1910
   constexpr const optional<const value_type*>* function_args<>::types;
diff --git a/build2/function.hxx b/build2/function.hxx
index 5b84a69..728e613 100644
--- a/build2/function.hxx
+++ b/build2/function.hxx
@@ -221,12 +221,12 @@ namespace build2
   class function_family
   {
   public:
-    // The default thunk catches invalid_argument and issues diagnostics
-    // by assuming it is related to function arguments and contains useful
-    // description.
+    // The call() function above catches invalid_argument and issues
+    // diagnostics by assuming it is related to function arguments and
+    // contains useful description.
     //
-    // In order to implement a custom thunk (e.g., to catch additional extra
-    // exceptions), you would normally call the default implementation.
+    // In order to catch additional exceptions, you can implement a custom
+    // thunk which would normally call this default implementation.
     //
     static value
     default_thunk (const scope*, vector_view<value>, const function_overload&);
-- 
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