FileDiffViewer rendering does not complete until mouse-up

[basilevs]

Version

7.7.0.202604291911-m2

Operating System

MacOS

Eclipse version

Eclipse IDE for Java Developers (includes Incubating components) Version: 2026-06 M2 (4.40.0 M2) Build id: 20260430-0613 OS: Mac OS X, v.26.4.1, aarch64 / cocoa Java vendor: Eclipse Adoptium Java runtime version: 21.0.10+7-LTS Java version: 21.0.10

Bug description

File list in a changeset shows partial render until mouse-up in graph viewer.

This is obviously JFace/SWT bug, but I can't reproduce it without eGit, so I hope someone more proficient with eGit can properly report a bug upstream.

Actual behavior

The list of files in a changeset is rendered partially:

Screen.Recording.2026-05-14.at.21.18.00.mov

Expected behavior

The list of files should be either completely rendered on mouse-down, or not show any changes.

Relevant log output

Other information

Initially discovered in eclipse-platform/eclipse.platform.swt#3260

[basilevs]

@Phillipus do you observe this too?

[Phillipus]

@Phillipus do you observe this too?

Yes I see the same behaviour.

[tomaswolf]

This is strange.

I do see the same on MacOS 13.7.7, Eclipse 2025-12 (4.38.0), EGit 7.6.0.

I do not see this in a runtime Eclipse started from that 2025-12 Eclipse running on an 4.36.0 target (using EGit master).

So it might be some change in SWT/Mac or in JFace between 4.36.0 and 4.38.0, or it might be due to the runtime Eclipse not using the binary launcher.

I'm not aware of any changes in this area in EGit, so it most likely is indeed an SWT problem.

Guess I'll have to try with a runtime Eclipse using a 4.38 target.

[Phillipus]

I do not see this in a runtime Eclipse started from that 2025-12 Eclipse running on an 4.36.0 target (using EGit master).

What Java version and distribution do you use for the target launch?

[tomaswolf]

It is reproducible in a runtime Eclipse using a 4.38 target. So unrelated to the JDK used, which happens to be Temurin 21.0.7.

I'll try a 4.37 target next. Kind of a coarse-grain bisect.

[Phillipus]

So unrelated to the JDK used

The runtime Eclipse launch will use the java binary rather than the Equinox launcher. Each can be compiled using different macOS SDKs which affects SWT behaviour.

[basilevs]

To get version of SDK your launcher uses, do:

otool -l /Library/Java/JavaVirtualMachines/temurin-21.jdk/Contents/Home/bin/java |grep sdk

[tomaswolf]

If it's reproducible in a runtime Eclipse (all launched with Temurin 21.0.7), it's unrelated to the MacOS SDK used the launcher was compiled against.

FWIW, that otool command reports "sdk 14.0".

Anyway, I have to correct myself: It's partly reproducible in a runtime Eclipse started against a 4.36, 4.37, or 4.38 target. (All on MacOS 13.7.7, using Temurin 21.0.7). It reproduces only if the viewer bottom-right is wide enough to show the full file paths. Does not reproduce if the viewer is smaller such that the file paths are longer than the viewer width. (So if all file paths fit the view, the issue reproduces. If one of them extends beyond the view's right edge, it's not reproducible.)

That viewer is a CommitFileDiffViewer, which extends TableViewer.

[basilevs]

I've managed to reproduce the bug with pure JFace snippet. The missing part were style constants.
The snippet reproducer is less stable though.

package org.eclipse.jface.snippets.viewers;

import java.util.List;

import org.eclipse.jface.layout.FillLayoutFactory;
import org.eclipse.jface.viewers.ArrayContentProvider;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.ListViewer;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.Shell;

public class TableViewerSetInputDemo {

	record Datum(String name, List<?> data) {

		@Override
		public final String toString() {
			return name;
		}

	}

	public static void main(String[] args) {
		Shell shell = new Shell();
		shell.setMinimumSize(300, 300);

		FillLayoutFactory.fillDefaults().applyTo(shell);

		ListViewer selector = new ListViewer(shell);
		selector.setLabelProvider(new LabelProvider());
		selector.setContentProvider(ArrayContentProvider.getInstance());
		// @formatter:off
		selector.setInput(new Datum[] {
			new Datum("long values", List.of(
					"1 very long long long long long long string 1",
						"2 very long long long long long long string 2")),
			new Datum("short values", List.of(
					"1 short string 1",
						"2 short string 2")),
			new Datum("2 short values 2", List.of(
					"3 short string 4",
					"4 short string 5"))
		});
		TableViewer viewer = new TableViewer(shell,
				SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER | SWT.VIRTUAL | SWT.FULL_SELECTION);
		selector.addSelectionChangedListener(event -> {
			shell.getDisplay().asyncExec(() -> {
				try {
					viewer.getControl().setRedraw(false);
					IStructuredSelection selection = (IStructuredSelection) event.getSelection();
					Datum datum = (Datum) selection.getFirstElement();
					viewer.setInput(datum == null ? null : datum.data());
				} finally {
					viewer.getControl().setRedraw(true);
				}
			});
		});

		viewer.setLabelProvider(new FileDiffLabelProvider(new RGB(255, 255, 255)));
		viewer.setContentProvider(ArrayContentProvider.getInstance());
		shell.open();
		shell.pack();
		while (!shell.isDisposed()) {
			shell.getDisplay().readAndDispatch();
		}

	}

}

To reproduce:

• create Java Application launch configuration and add all dependencies manually on Dependencies tab (modern PDE has broken Plugin Dependencies in Java applications).
• run
• click on each item in left pane,
• click and hold on each item