Reimplement error-next (#2775)

This is often more convenient for checking errors than the dialog.
At least if the errors are obvious.

I re-introduce the binding this had up to LyX 1.4.

lib/RELEASE-NOTES

@@ -17,6 +17,9 @@
 
 !!!The following new LyX functions have been introduced in 2.5:
 
+- The re-introduced function error-next movers the cursor to the next
+  LaTeX error in the current buffer.
+
 - The new function errors-show re-displays the (e.g., LaTeX) errors dialog 
   if there had been any processing errors.
 

lib/bind/cua.bind

@@ -129,6 +129,7 @@ Format 5
 \bind "S-F6"			"tab-group-previous"
 \bind "C-F6"			"buffer-next"
 \bind "C-S-F6"			"buffer-previous"
+\bind "C-g"			"error-next"
 \bind "F7"			"dialog-show spellchecker"
 \bind "S-F7"			"thesaurus-entry"
 

lib/ui/stdmenus.inc

@@ -605,6 +605,7 @@ Menuset
 #
 	Menu "navigate"
 		Submenu "Bookmarks|B" "navigate_bookmarks"
+		Item "Next Error|E" "error-next"
 		Item "Next Note|N" "note-next"
 		Item "Next Change|C" "change-next"
 		Item "Next Cross-Reference|R" "reference-next"

src/FuncCode.h

@@ -513,7 +513,8 @@ enum FuncCode
 	// 400
 	LFUN_REFERENCE_TO_PARAGRAPH,    // spitz, 20240728
 	LFUN_WORD_INVERTCASE,           // lasgouttes 20241015
-	LFUN_ERRORS_SHOW,               // spitz 20241231
+	LFUN_ERRORS_SHOW,               // spitz 20241231,
+	LFUN_ERROR_NEXT,                // spitz 20200101,
 	LFUN_LASTACTION                 // end of the table
 };
 

src/LyXAction.cpp

@@ -1588,6 +1588,14 @@ void LyXAction::init()
  */
 		{ LFUN_ERRORS_SHOW, "errors-show", NoBuffer, Edit },
 
+/*!
+ * \var lyx::FuncCode lyx::LFUN_ERROR_NEXT
+ * \li Action: Moves the cursor to the beginning of next LaTeX error.
+ * \li Syntax: error-next
+ * \endvar
+ */
+		{ LFUN_ERROR_NEXT, "error-next", ReadOnly, Edit },
+
 /*!
  * \var lyx::FuncCode lyx::LFUN_ERT_INSERT
  * \li Action: Inserts an ERT inset.

src/frontends/qt/GuiView.cpp

@@ -2192,6 +2192,35 @@ void GuiView::errors(string const & error_type, bool from_master)
 }
 
 
+bool GuiView::nextError(string const & error_type, bool from_master, bool testonly)
+{
+	BufferView const * const bv = currentBufferView();
+	if (!bv)
+		return false;
+
+	Buffer const & buf = from_master
+			? *(bv->buffer().masterBuffer())
+			: bv->buffer();
+
+	ErrorList const & el = buf.errorList(error_type);
+
+	if (el.empty())
+		return false;
+
+	for (auto const & err : el) {
+		if (TexRow::isNone(err.start) || TexRow::getDocIteratorsFromEntries(err.start, err.end, buf).first <= bv->cursor())
+			continue;
+		if (testonly)
+			return true;
+		DispatchResult dr;
+		dispatch(TexRow::goToFunc(err.start, err.end), dr);
+		return true;
+	}
+
+	return false;
+}
+
+
 void GuiView::updateTocItem(string const & type, DocIterator const & dit)
 {
 	d.toc_models_.updateItem(toqstr(type), dit);
@@ -2679,6 +2708,17 @@ bool GuiView::getStatus(FuncRequest const & cmd, FuncStatus & flag)
 		break;
 	}
 
+	case LFUN_ERROR_NEXT: {
+		if (!buf || (buf->errorList(d.last_export_format).empty()
+			     && buf->masterBuffer()->errorList(d.last_export_format).empty())) {
+			enable = false;
+			break;
+		}
+		// We guess it's from master if the single buffer list is empty
+		bool const from_master = currentBufferView()->buffer().errorList(d.last_export_format).empty();
+		enable = nextError(d.last_export_format, from_master, true);
+	}
+
 	case LFUN_COMMAND_EXECUTE:
 	case LFUN_MESSAGE:
 	case LFUN_MENU_OPEN:
@@ -4929,6 +4969,16 @@ void GuiView::dispatch(FuncRequest const & cmd, DispatchResult & dr)
 			break;
 		}
 
+		case LFUN_ERROR_NEXT: {
+			// We guess it's from master if the single buffer list is empty
+			bool const from_master = bv->buffer().errorList(d.last_export_format).empty();
+			if (nextError(d.last_export_format, from_master)) {
+				dr.forceBufferUpdate();
+				dr.screenUpdate(Update::Force);
+			}
+			break;
+		}
+
 		case LFUN_MESSAGE:
 			dr.setMessage(cmd.argument());
 			break;

src/frontends/qt/GuiView.h

@@ -177,6 +177,9 @@ public:
 	void updateTocItem(std::string const &, DocIterator const &) override;
 	//@}
 
+	/// move to next error
+	bool nextError(std::string const &, bool from_master = false, bool testonly = false);
+
 	///
 	TocModels & tocModels();