History panel should be configurable

[anavarre]

At View > History, you can open up the Git log in the Theia UI. Great feature. However, if you happen to have more than a hundred commits, it becomes extremely slow and makes the IDE interface unusable until all commits and changes within are rendered in the panel.

I could not find a way to make this configurable (in 90% of the cases you really should only care about the 10 latest commits right?) while I'm fairly certain it'd make a huge difference performance wise.

Could it be something for Theia to implement?

[vince-fugnitto]

@anavarre thank you for the discussion, from what I understand we should limit 100 entries, and perhaps prompt to load more:

theia/packages/scm-extra/src/browser/history/scm-history-contribution.ts

Line 31 in 0a960a6

export const SCM_HISTORY_MAX_COUNT = 100;

theia/packages/scm-extra/src/browser/history/scm-history-widget.tsx

Lines 400 to 417 in 0a960a6

	protected doLoadMoreRows(params: IndexRange): Promise<any> {
	let resolver: () => void;
	const promise = new Promise<void>(resolve => resolver = resolve);
	const lastRow = this.scmNodes[params.stopIndex - 1];
	if (ScmCommitNode.is(lastRow)) {
	const toRevision = lastRow.commitDetails.id;
	this.addCommits({
	range: { toRevision },
	maxCount: SCM_HISTORY_MAX_COUNT,
	uri: this.options.uri
	}).then(() => {
	this.allowScrollToSelected = false;
	this.onDataReady();
	resolver();
	});
	}
	return promise;
	}

I believe there might be a bug where it is not respected properly at the moment, but we should support the mechanism of passing around the maxCount.

[anavarre]

Interesting, thanks. Take my 100 threshold with a grain of salt. Perhaps it was exactly 100 commits returned, I didn't count. I just know it took 1-2mn to render for multiple people and the only obvious way to improve the experience is to have a low limit.

What would be ideal is to have export const SCM_HISTORY_MAX_COUNT = 10; and have a text field in the settings where this would be a configurable setting. Alternatively, a dropdown with a few options e.g. 10, 30, 50, 100.

In the Git UI, it would also be a nice to have to be able to click on a "Load more" button or, when you're at the bottom of the panel, scroll down and fetch more commits, similar to an infinite scroll feature if you will.

[vince-fugnitto]

What would be ideal is to have export const SCM_HISTORY_MAX_COUNT = 10; and have a text field in the settings where this would be a configurable setting. Alternatively, a dropdown with a few options e.g. 10, 30, 50, 100.

10 might be a bit low for a default but pull-requests are always welcome!

[anavarre]

10 might be low but 100 certainly seems high considering the performance hit. Based on your experience, what would you think would be a good middle ground?

[vince-fugnitto]

I've ran the desktop example application locally and did not seem to notice an issue so it might be related to the network.

Note that while I mentioned 100 it does not actually seem to be respected as I highlighted in #11371 (comment) since I can load all commits of the theia repo (back to the initial commit) when the view is first opened.

initial-commit.mp4

I believe the first part would be to ensure we respect a max, and then we can see if 100 is good or not as a default.

[anavarre]

#11376

[anavarre]

Key takeways from this discussion:

• We are hardcoding the Git history max count at 100 but it doesn't seem to be respected ATM. scm: history does not respect max count #11376 to address the bug.
• After this bug is fixed, we will be able to revisit whether 100 makes sense or whether we need to aim for a lower hardcoded value.
• Theia maintainers are looking to get external contributions to make this a configurable setting for end users to enter the value that would best suit their needs. scm: history max count should be configurable #11378 is the feature request.