Automatically Expand Paths of single children: eclipse.platform#1063

[Wittmaxi]

Enable expanding paths of single children in one click

In some cases cases, I expect all folders to open recursively when clicking on com.wittmaxi.plugin

com.wittmaxi.plugin
└─src
└─org.foo.com
└─Bar.java

A new feature in SWT allows for this feature, this PR enables that feature in the Package Explorer.

Implements
eclipse-platform/eclipse.platform.ui#1063

An analogous PR for the Project-Explorer was merged in platform/ui.

What it does

In the project explorer and similar treeviews, when expanding a folder that contains a singular folder, I expect that folder to recursively expand as well.

Examples

In these cases, I expect all folders to open recursively

com.wittmaxi.plugin
 └─src
    └─org.foo.com
       └─Bar.java

In IntelliJ

(click on src)

A few things are yet to be discussed (help wanted!):

• Should this be always enabled by default or should there be a preference to toggle this behavior?
• What should be the default "auto-expansion-depth"? 10 Nodes (as I have arbitrarily set it for this PR)? Or infinitely many? Should there be a preference for those values?

For reference, this is how other tools handle this case:

• IntelliJ will auto-expand to infinite depth (tested with 106 nested folders)
• VScode will auto-expand the entire depth but will not actually display the folders and rather show the entire path in the folder-node: like so: "\a...\a\a\a\a"

A similar PR was created in eclipse.platform for the "project explorer": eclipse-platform/eclipse.platform.ui#1742

How to test

Create a path of folders that contains only singular children.
Close the entire path and then open the path.
With this change, the entire path will be opened at once instead of having to click open each node individually.

Author checklist

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