Send the fetched signal in RowLoader even when no rows where fetched

MKleusberg · MKleusberg · commit 9594115ef3b5 · 2019-07-06T23:05:57.000+02:00
Always send the fetched() signal when a RowLoader thread has finished a fetch task. Before this the signal was only sent when some data was actually retrieved from the task. This fixes some rare problems in the Execute SQL tab where the query for determining the row count of a SELECT statement changes something, so the subsequent row loading task does not return any rows after all. The only case I know of is when loading an extension using the 'SELECT load_extension()' function. The load_extension function is actually called twice when SQLite for some reason reports that rows where returned from this statement. These calls are: SELECT COUNT(*) FROM (SELECT load_extension('...')); SELECT load_extension('...'); After the first call is executed, the extension is loaded. So the second call does not return any rows and we indefinitely wait for the rows we expect. Strangely enough this only happens for some extensions. The change here should have no side effects becaue the signal is only connected to one slot which skips most steps when no rows where fetched. See issue #1932.
diff --git a/src/RowLoader.cpp b/src/RowLoader.cpp
@@ -255,6 +255,5 @@ void RowLoader::process (Task & t)
         sqlite3_finalize(stmt);
     }
 
-    if(row != t.row_begin)
-        emit fetched(t.token, t.row_begin, row);
+    emit fetched(t.token, t.row_begin, row);
 }

Original file line number	Diff line number	Diff line change
`@@ -255,6 +255,5 @@ void RowLoader::process (Task & t)`
`255`	`255`	`sqlite3_finalize(stmt);`
`256`	`256`	`}`
`257`	`257`
`258`		`- if(row != t.row_begin)`
`259`		`- emit fetched(t.token, t.row_begin, row);`
	`258`	`+ emit fetched(t.token, t.row_begin, row);`
`260`	`259`	`}`