Feature: Added experimental support for flattening folders

[devin-slothower]

Resolved / Related Issues

To prevent extra work, all changes to the Files codebase must link to an approved issue marked as Ready to build. Please insert the issue number following the hashtag with the issue number that this Pull Request resolves.

• For Feature: Add support for flattening folders #12367

Steps used to test these changes

Stability is a top priority for Files and all changes are required to go through testing before being merged into the repo. Please include a list of steps that you used to test this PR.

1. Tested many nested folders both blank and with data.
2. Tested with merging duplicate files.
3. Assured the Flatten popup only appears for a single selected folder.
4. Ran through a bunch of scenarios trying to crash with/without a debugger.

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[yaira2]

This is amazing @devin-slothower! Just a heads-up, you only need to add the strings to the en-us file. The other files will automatically update when we sync with Crowdin

[0x5bfa]

Using Actions is great idea!

[yaira2]

@devin-slothower I pushed a commit to sort out the resource files. In short, the only resource file modified in this PR is now the en-us file. Thanks!

[yaira2]

Fyi @Jay-o-Way

[Jay-o-Way]

I think the resulting action needs to be clear: what files will end up where? Specifically - what will become the root folder? A reasonable expectation can be that, when applying this on one folder, all the the SUBfolders will be dissolved, but the selected folder will remain. In stead, everything is "dumped" in the above folder. But I suppose this behavior makes sense to generalize the different triggering scenarios: selecting one or more folders, selecting one or more files...

[yaira2]

Would an optional dialog with a preview of the changes help?

[yaira2]

@devin-slothower what's the behavior for duplicate files?

[devin-slothower]

@devin-slothower what's the behavior for duplicate files?

The current behavior is just to keep the duplicate files where they are and move all non duplicates to their respective place, only removing flattened folders once they no longer contain anything.

[yaira2]

I don’t want to complicate things, so this isn’t a blocker, but it would be great if we could handle this better. Here are some ideas:

• Show a conflict dialog and let the user choose an action.
• Add a prompt before flattening folders, allowing the user to set a default behavior for any conflicts.
• Display a prompt at the end of the operation with a list of files that weren’t moved.

Personally, I lean towards the second idea, but I’m open to discussion. We should probably handle this in a separate PR once we agree on a solution.

[devin-slothower]

I don’t want to complicate things, so this isn’t a blocker, but it would be great if we could handle this better. Here are some ideas:

• Show a conflict dialog and let the user choose an action.
• Add a prompt before flattening folders, allowing the user to set a default behavior for any conflicts.
• Display a prompt at the end of the operation with a list of files that weren’t moved.

Personally, I lean towards the second idea, but I’m open to discussion. We should probably handle this in a separate PR once we agree on a solution.

I think the best option would be to handle conflicts similar to the default file manager where the user is prompted for an action, should a conflict arise, prior to anything being moved. I would recommend the following options (with some tweaking to the names):

• Replace
• Rename (Either prompting for a new name, or automatically appending a suffix like "file - 1.txt", "file - 2.txt", etc)
• Skip
• Cancel

[yaira2]

We already have a conflicts prompt with those options, so most of the work is already done.

[0x5bfa]

It's a bit confusing but here's how to use. The dialog class is shared among multiple file system operations and dialog conflict resolve is one of them. There's an enum property to get how to resolve for each.

[yaira2]

@devin-slothower I made some adjustments based on user feedback. I also updated the list in #12367 to track improvements to make at a later time.

• Updated the wording to “Flatten to root” and changed the destination to be the selected folder.
• Removed the "Flatten single action".
• Added a "Flatten folder" action. This isn’t functional yet but opens a dialog that will contain more advanced options in the future.

From my perspective, this PR is ready to merge, but I’ll leave it open for a couple of hours to see if there is any other feedback.

[0x5bfa]

Looks good!

[0x5bfa]

Suggested change

	using Microsoft.Extensions.Logging;
	using System.IO;
	using Windows.Storage;
	using Microsoft.UI.Xaml.Controls;
	using Windows.Foundation.Metadata;
	using Files.Shared.Helpers;
	using Files.Shared.Helpers;
	using Microsoft.Extensions.Logging;
	using Microsoft.UI.Xaml.Controls;
	using System.IO;
	using Windows.Storage;
	using Windows.Foundation.Metadata;

[hishitetsu]

LGTM