Fix crashes related to macros and instant preview

* Fix crash when zooming after latex failed to generate any output for previews.
  This was new in 2.1.4, so no status line is needed.

* Fix crash when copying macros with instant preview on.

src/graphics/PreviewLoader.cpp

@@ -709,6 +709,7 @@ void PreviewLoader::Impl::finishedGenerating(pid_t pid, int retval)
 	if (git == in_progress_.end()) {
 		lyxerr << "PreviewLoader::finishedGenerating(): unable to find "
 			"data for PID " << pid << endl;
+		finished_generating_ = true;
 		return;
 	}
 
@@ -717,8 +718,11 @@ void PreviewLoader::Impl::finishedGenerating(pid_t pid, int retval)
 	LYXERR(Debug::GRAPHICS, "PreviewLoader::finishedInProgress("
 				<< retval << "): processing " << status
 				<< " for " << command);
-	if (retval > 0)
+	if (retval > 0) {
+		in_progress_.erase(git);
+		finished_generating_ = true;
 		return;
+	}
 
 	// Read the metrics file, if it exists
 	vector<double> ascent_fractions(git->second.snippets.size());

src/mathed/MacroTable.h

@@ -69,6 +69,8 @@ public:
 	char const * MathMLtype() const;
 	///
 	void setSymbol(latexkeys const * sym) { sym_ = sym; }
+	///
+	DocIterator const & pos() { return pos_; }
 
 	/// lock while being drawn to avoid recursions
 	int lock() const { return ++lockCount_; }

src/mathed/MathMacro.cpp

@@ -176,6 +176,14 @@ void MathMacro::assign(MathMacro const & that)
 		if (p)
 			p->setOwner(this);
 	}
+	if (macro_ && lyxrc.preview == LyXRC::PREVIEW_ON) {
+		// We need to update macro_ by ourselves because in this case
+		// MathData::metrics() is not called when selecting a math inset
+		DocIterator const & pos = macroBackup_.pos();
+		macro_ = pos.buffer() ? pos.buffer()->getMacro(name(), pos) : 0;
+		if (!macro_)
+			macro_ = &macroBackup_;
+	}
 }
 
 

status.21x

@@ -183,6 +183,8 @@ What's new
 
 - Fix crash when copying macros with arguments (bug 9418).
 
+- Fix crash when copying macros with instant preview on.
+
 - Fix bad cursor font in some cases after changing layout (bug 4294).
 
 - Fix name and hint of figure captions in documents using the class aastex.