Show progress when pre-calculating the AST during save #2414

[fedejeanne]

What it does

Fixes #2414

Show a progress dialog (after a delay) if the precalculation of the AST during a save takes too long.

Requires

• Show ProgressMonitorJobsDialog after delay in ProgressManager.run eclipse-platform/eclipse.platform.ui#3147

This is to avoid the "flickering" of the progress dialog showing up and immediately disappearing when the calculation of the AST takes just a few milliseconds.

How to test

• Activate a save action that requires an AST, e.g. "Organize imports"
• Open a big class and make a modification
• Save

Expected outcome
If the AST takes a while to calculate then you should see a (non-cancelable) progress dialog.

---

Note

Since the methods that end up creating the AST do not really report progress with the monitor they receive, the progress dialog doesn't really show any progress (the bar does not move). I couldn't find any way around it but I'm open to suggestions.

---

A small hack to help testing
Add a delay to org.eclipse.jdt.core.dom.ASTParser.createAST(IProgressMonitor)

for (int i=0; i<5;i++) {
	try {
		Thread.sleep(1000);
	} catch (InterruptedException e) {
		e.printStackTrace();
	}
}

Author checklist

• I have thoroughly tested my changes
• The change is following the coding conventions
• I have signed the Eclipse Contributor Agreement (ECA)

[fedejeanne]

Test failures are unrelated. I ran them all and they pass locally.

[carstenartur]

Test failures are unrelated. I ran them all and they pass locally.

In general you cannot conclude that there is no issue when tests run through locally. It might be right in this case but is not in general.
See
#2213 (comment)

[fedejeanne]

@carstenartur the test failures are unrelated and they are documented in #2423.

Since that issue has been fixed last week (see https://ci.eclipse.org/jdt/job/eclipse.jdt.ui-github/job/master/474/testReport/), I rebased on master. That should get rid of the errors.

[fedejeanne]

I'm drafting this PR since I have no intention of merging it before M1