[LyX/master] Improved fix for edit button

[Richard Kimberly Heck]

commit 3c25899eab265aa8d5ca6af48b669650dff34298
Author: Richard Kimberly Heck <rikiheck at lyx.org>
Date:   Mon Aug 31 11:20:49 2020 -0400

    Improved fix for edit button
---
 src/frontends/qt/GuiInclude.cpp |   36 +++++++++++-------------------------
 1 files changed, 11 insertions(+), 25 deletions(-)

diff --git a/src/frontends/qt/GuiInclude.cpp b/src/frontends/qt/GuiInclude.cpp
index f278351..5949d17 100644
--- a/src/frontends/qt/GuiInclude.cpp
+++ b/src/frontends/qt/GuiInclude.cpp
@@ -296,24 +296,9 @@ void GuiInclude::edit()
 	QString const fname = filenameED->text();
 	string const bpath = buffer().filePath();
 	string const absfname = support::makeAbsPath(fromqstr(fname), bpath).absFileName();
-	FileName const absFileName(absfname);
-	Buffer const * buffer = theBufferList().getBuffer(absFileName);
-	if (!buffer) {
-		// The Buffer is not already open, so try to open it.
-		if (!absFileName.exists()) {
-			Alert::warning(_("File does not exist"),
-				bformat(_("The requested file\n\t%1$s\ndoes not exist."),
-					from_utf8(absfname)));
-			return;
-		}
-		dispatch(FuncRequest(LFUN_BUFFER_NEW, absfname));
-		// Did we succeed?
-		if (!theBufferList().getBuffer(absFileName)) {
-			// We should already have had an error message.
-			return;
-		}
-	}
-	// Switch to the requested Buffer
+	// The button is enabled only if the document is already open.
+	// If something goes wrong and it is not, we'll get an error
+	// message from the dispatch. So no need for one here.
 	dispatch(FuncRequest(LFUN_BUFFER_SWITCH, absfname));
 }
 
@@ -321,8 +306,7 @@ void GuiInclude::edit()
 bool GuiInclude::isValid()
 {
 	QString fname = filenameED->text();
-	bool fempty = fname.isEmpty();
-	if (fempty || !validate_listings_params().empty()) {
+	if (fname.isEmpty() || !validate_listings_params().empty()) {
 		editPB->setEnabled(false);
 		return false;
 	}
@@ -335,15 +319,17 @@ bool GuiInclude::isValid()
 		return true;
 	}
 	// Do we have a LyX filename?
-	if (!support::isLyXFileName(fromqstr(fname))) {
+	if (!isLyXFileName(fromqstr(fname))) {
 		okbutton->setText("OK");
 		return false;
 	}
 	string const bpath = buffer().filePath();
-	QString absfname = makeAbsPath(fname, toqstr(bpath));
-	bool const fexists = QFile::exists(absfname);
-	okbutton->setText(fexists ? "OK" : "Create");
-	editPB->setEnabled(fexists);
+	// Path might be relative to current Buffer, so make absolute
+	FileName const absfname = support::makeAbsPath(fromqstr(fname), bpath);
+	// Set OK button text according to whether file already exists
+	okbutton->setText(absfname.exists() ? "OK" : "Create");
+	// enable edit button iff file is open in some Buffer
+	editPB->setEnabled(theBufferList().getBuffer(absfname));
 	return true;
 }