[libsigc++2] trackable, slot, signal: Remove noexcept specifications

[Kjell Ahlstedt <kjellahl src gnome org>]

commit b53b58b7816c20b3d09f1a6fa6ce98da1f003edf
Author: Kjell Ahlstedt <kjell ahlstedt bredband net>
Date:   Sun Nov 8 10:03:28 2015 +0100

    trackable, slot, signal: Remove noexcept specifications
    
    * sigc++/functors/macros/slot.h.m4:
    * sigc++/functors/slot_base.[h|cc]:
    * sigc++/signal_base.[h|cc]:
    * sigc++/trackable.[h|cc]: Remove noexcept from the move operators.
    Bug #756484.

 sigc++/functors/macros/slot.h.m4 |    4 ++--
 sigc++/functors/slot_base.cc     |    4 ++--
 sigc++/functors/slot_base.h      |    8 ++++++--
 sigc++/signal_base.cc            |    4 ++--
 sigc++/signal_base.h             |    4 ++--
 sigc++/trackable.cc              |    4 ++--
 sigc++/trackable.h               |    9 +++++++--
 7 files changed, 23 insertions(+), 14 deletions(-)
---
diff --git a/sigc++/functors/macros/slot.h.m4 b/sigc++/functors/macros/slot.h.m4
index 0a141a2..4e9b00f 100644
--- a/sigc++/functors/macros/slot.h.m4
+++ b/sigc++/functors/macros/slot.h.m4
@@ -91,7 +91,7 @@ FOR(1, $1,[
    * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
    * @param src The existing slot to move or copy.
    */
-  slot$1(slot$1&& src) noexcept
+  slot$1(slot$1&& src)
     : slot_base(std::move(src))
     {}
 
@@ -110,7 +110,7 @@ FOR(1, $1,[
    * @param src The slot from which to move or copy.
    * @return @p this.
    */
-  slot$1& operator=(slot$1&& src) noexcept
+  slot$1& operator=(slot$1&& src)
   {
     slot_base::operator=(std::move(src));
     return *this;
diff --git a/sigc++/functors/slot_base.cc b/sigc++/functors/slot_base.cc
index 7500d84..9340b02 100644
--- a/sigc++/functors/slot_base.cc
+++ b/sigc++/functors/slot_base.cc
@@ -124,7 +124,7 @@ slot_base::slot_base(const slot_base& src)
   }
 }
 
-slot_base::slot_base(slot_base&& src) noexcept
+slot_base::slot_base(slot_base&& src)
 : rep_(nullptr),
   blocked_(src.blocked_)
 {
@@ -219,7 +219,7 @@ slot_base& slot_base::operator=(const slot_base& src)
   return *this;
 }
 
-slot_base& slot_base::operator=(slot_base&& src) noexcept
+slot_base& slot_base::operator=(slot_base&& src)
 {
   if (src.rep_ == rep_)
   {
diff --git a/sigc++/functors/slot_base.h b/sigc++/functors/slot_base.h
index ec7679a..6577574 100644
--- a/sigc++/functors/slot_base.h
+++ b/sigc++/functors/slot_base.h
@@ -244,6 +244,10 @@ class SIGC_API slot_base : public functor_base
 {
   typedef internal::slot_rep rep_type;
 
+  // Move operations are not declared noexcept because
+  // 1. they may copy instead of move
+  // 2. when they don't copy, they call src.rep_->notify_callbacks(), which
+  //    may throw an exception.
 public:
   /// Constructs an empty slot.
   slot_base();
@@ -262,7 +266,7 @@ public:
    * If @p src is connected to a parent (e.g. a signal), it is copied, not moved.
    * @param src The existing slot to move or copy.
    */
-  slot_base(slot_base&& src) noexcept;
+  slot_base(slot_base&& src);
 
   ~slot_base();
 
@@ -344,7 +348,7 @@ public:
    * @param src The slot from which to move or copy.
    * @return @p this.
    */
-  slot_base& operator=(slot_base&& src) noexcept;
+  slot_base& operator=(slot_base&& src);
 
 public: // public to avoid template friend declarations
   /** Typed slot_rep object that contains a functor. */
diff --git a/sigc++/signal_base.cc b/sigc++/signal_base.cc
index 64226b8..7885a53 100644
--- a/sigc++/signal_base.cc
+++ b/sigc++/signal_base.cc
@@ -167,7 +167,7 @@ signal_base::signal_base(const signal_base& src)
   impl_->reference();
 }
 
-signal_base::signal_base(signal_base&& src) noexcept
+signal_base::signal_base(signal_base&& src)
 : trackable(std::move(src)),
   impl_(std::move(src.impl_))
 {
@@ -248,7 +248,7 @@ signal_base& signal_base::operator=(const signal_base& src)
   return *this;
 }
 
-signal_base& signal_base::operator=(signal_base&& src) noexcept
+signal_base& signal_base::operator=(signal_base&& src)
 {
   if (src.impl_ == impl_) return *this;
 
diff --git a/sigc++/signal_base.h b/sigc++/signal_base.h
index 1842b02..03ae156 100644
--- a/sigc++/signal_base.h
+++ b/sigc++/signal_base.h
@@ -290,13 +290,13 @@ struct SIGC_API signal_base : public trackable
 
   signal_base(const signal_base& src);
 
-  signal_base(signal_base&& src) noexcept;
+  signal_base(signal_base&& src);
 
   ~signal_base();
 
   signal_base& operator=(const signal_base& src);
 
-  signal_base& operator=(signal_base&& src) noexcept;
+  signal_base& operator=(signal_base&& src);
 
   /** Returns whether the list of slots is empty.
    * @return @p true if the list of slots is empty.
diff --git a/sigc++/trackable.cc b/sigc++/trackable.cc
index 385f97c..9faabc1 100644
--- a/sigc++/trackable.cc
+++ b/sigc++/trackable.cc
@@ -43,7 +43,7 @@ trackable::trackable(const trackable& /*src*/)
 //
 // If trackable's move constructor is modified, check if Glib::Object's
 // move constructor should be modified similarly.
-trackable::trackable(trackable&& src) noexcept
+trackable::trackable(trackable&& src)
 : callback_list_(nullptr)
 {
   src.notify_callbacks();
@@ -57,7 +57,7 @@ trackable& trackable::operator=(const trackable& src)
   return *this;
 }
 
-trackable& trackable::operator=(trackable&& src) noexcept
+trackable& trackable::operator=(trackable&& src)
 {
   if(this != &src)
   {
diff --git a/sigc++/trackable.h b/sigc++/trackable.h
index af8042a..b82bbbb 100644
--- a/sigc++/trackable.h
+++ b/sigc++/trackable.h
@@ -108,15 +108,20 @@ private:
  */
 struct SIGC_API trackable
 {
+  // Concerning noexcept specifications:
+  // libsigc++ does not have complete control of what happens when notify_callbacks()
+  // is called. It may throw an exception. A method that calls notify_callbacks()
+  // shall not be declared noexcept.
+
   trackable();
 
   trackable(const trackable& src);
 
-  trackable(trackable&& src) noexcept;
+  trackable(trackable&& src);
 
   trackable& operator=(const trackable& src);
 
-  trackable& operator=(trackable&& src) noexcept;
+  trackable& operator=(trackable&& src);
 
   ~trackable();