Fix file history for sizes <= 1200 entries

Author: cruessler

src/components/file_revlog.rs

@@ -226,16 +226,40 @@ impl FileRevlogComponent {
 		if let Some(git_log) = &mut self.git_log {
 			let table_state = self.table_state.take();
 
-			let start = table_state.selected().unwrap_or(0);
-
 			let commits = get_commits_info(
 				&self.repo_path.borrow(),
-				&git_log.get_slice(start, SLICE_SIZE)?,
+				&git_log.get_slice(0, SLICE_SIZE)?,
 				self.current_width.get(),
 			);
 
 			if let Ok(commits) = commits {
-				self.items.set_items(start, commits);
+				// 2023-04-12
+				//
+				// There is an issue with how windowing works in `self.items` and
+				// `self.table_state`. Because of that issue, we currently have to pass
+				// `0` as the first argument to `set_items`. If we did not do that, the
+				// offset that is kept separately in `self.items` and `self.table_state`
+				// would get out of sync, resulting in the table showing the wrong rows.
+				//
+				// The offset determines the number of rows `render_stateful_widget`
+				// skips when rendering a table. When `set_items` is called, it clears
+				// its internal `Vec` of items and sets `index_offset` based on the
+				// parameter passed. Unfortunately, there is no way for us to pass this
+				// information, `index_offset`, to `render_stateful_widget`. Because of
+				// that, `render_stateful_widget` assumes that the rows provided by
+				// `Table` are 0-indexed while in reality they are
+				// `index_offset`-indexed.
+				//
+				// This fix makes the `FileRevlog` unable to show histories that have
+				// more than `SLICE_SIZE` items, but since it is broken for larger
+				// histories anyway, this seems acceptable for the time being.
+				//
+				// This issue can only properly be fixed upstream, in `tui-rs`. See
+				// [tui-issue].
+				//
+				// [gitui-issue]: https://github.com/extrawurst/gitui/issues/1560
+				// [tui-issue]: https://github.com/fdehau/tui-rs/issues/626
+				self.items.set_items(0, commits);
 			}
 
 			self.table_state.set(table_state);