Nemo does not update empty folder status after moving a file

[kimimaru4000]

 * Nemo version 4.6.5
 * Is issue with desktop or windowed nemo?
 * Distribution - Linux Mint 20 Ulyana
 * NVIDIA GeForce RTX 2060 | Driver: 450.80.02
 * 64 bit

Issue
If you have an empty folder in List view and move a file into it, Nemo still indicates that the folder is empty. The arrow to the left showing the folder's contents will not appear until you re-open or refresh the directory containing the now non-empty folder.

Steps to reproduce

1. Have Nemo open in List view.
2. Navigate to a directory with an empty folder or create an empty folder.
3. Move a file into the empty folder. This can be a newly created file.
4. The folder still shows that it's empty.

Expected behaviour
After moving the file inside the folder, the folder updates to show that there is now a file inside it.

[Jeremy7701]

The demonstration is in list view; not icon view (as specified in the problem description).
I tried to reproduce the problem in both icon and list view but couldn't reproduce the problem.

[kimimaru4000]

The problem actually was in list view; sorry about that! Maybe this is related to a certain setting. Is there a way to export Nemo settings?

[fredcw]

Yes, I noticed this as well. In list view the folder should have a little arrow next to it that you can use to expand the contents if the folder is not empty. When you drag something into an empty folder, no arrow appears. But it will appear if you reload the view (Ctrl-R). It's hardly the worst bug ever but probably worth pointing it out nonetheless.

[gkatev]

I've also come here to report this problem! I see the "need info" label, can I help provide information?
The video accurately describes my experience.

• Create empty folder
• Drag'n'drop file to folder
• The item count updates correctly like on the video
• But, the arrow is not shown next to the folder that is now non-empty, forcing a folder refresh, which loses the tree-ed view state.

All this in list view.

[kimimaru4000]

@icarter09 What extra information is needed to proceed with this issue?

[mtwebster]

No extra info is needed. We're aware of this issue, but it's not trivial to fix. I'm considering reverting back to always showing the arrow, whether empty or not.

[kimimaru4000]

Thanks for the update @mtwebster. Do you mind sharing some technical information on why it's not trivial? To my understanding, when a file is moved into a folder successfully, the folder can never be empty, and I'm wondering what could be the underlying problem displaying an arrow in this case.

[gaellafond]

This bug is very irritating when manipulating large projects. If I have a set of folder opened multiple layers deep, when I refresh, it collapses the whole tree structure and I have to reopen all the folders, remembering which ones were opened. Always showing the arrow would be a good solution for me.

[gkatev]

Perhaps a useful workaround would be to not collapse the structure when refreshing (like dolphin), an all-around useful feature IMO. (I think dolphin further retains the structure with some navigation actions)

Theoretically, fixing the root cause might be more fitting (so that a refresh is never needed), but I expect that such problems always creep around the corner sooner or later (eg. I'm seeing an issue where generated files in an NTFS mount do not appear and I have to refresh for them to show up).

[fredcw]

I think this is a fairly insignificant bug as you would know anyway that the directory isn't empty if the just moved stuff there. I find the way it currently works is far better than always showing the arrow as that provides far less information and you'd always be trying to expand folders only to find them empty which I think is far more irritating and probably so to far more people.

[gkatev]

@fredcw I think the more important problem is (for me at least it is) that you can't tree-expand the folder after moving something into it. Indeed I agree, I am not too fond of having the arrow always showing either.

[Jeremy7701]

If you never showed an arrow, wouldn't that cover the case of empty/non-empty folders?

[gaellafond]

@gkatev I agree, keeping the folder structure expanded after refresh would be a good solution.

@fredcw The issue is not about knowing if the folder is empty but rather viewing the files in it. You can't see the files if you can't expand the folder structure. This is a real pain when the folder structure is generated. Every time I trigger a re-generation, I have to refresh the folder. If my objective is to compare the generated files against previous generations, I will have to refresh and re-expand the folder structure of the previous generations after every single attempt. NOTE: The generated folder structure is often really deep, like 10 folders deep. If the arrow was always showing, I would not need to refresh and would not need to re-expand the folder structure of the previous generations. That might seems like a very isolate case, but I'm facing this issue several times a week.

@Jeremy7701 Never showing the arrow would break the tree view feature in list view. You would not be able to expand a folder in list view.

[wahmit]

I have the same irritation. Keeping the folder structure expanded after refresh would be my preference. If that is difficult then displaying the arrows on all folders would be reasonable compromise; including the size column informs the user if the folder is empty.

[kimimaru4000]

I'd still like to understand the technical issues regarding this bug. Is it not possible to refresh just a single folder and/or keep the tree view intact on refresh?

I'm wondering why it'd be required to settle for anything less than the expected behavior from users. Other operating systems do not have this issue. @mtwebster would you please provide us with more details?

[mtwebster]

Only the active folder gets monitored for changes.

1. The current directory is loaded. While loading any child directories get their contents counted (first-level only) so those counts can be displayed.
   • If the addition/removal of a file from a listed folder is performed by nemo, the change will be seen, and arrow updated, because that folder will have been loaded to perform the transfer. Same if you have the listed folder open in another view elsewhere.
   • If the change is done from another program or terminal, the change will go unnoticed, unless the folder is also open in nemo somewhere.
2. When you click the arrow to expand the contents of a folder, at that point step 1 occurs to that folder - its children counted one level deep, arrows reflecting contents, etc..
   ..and so on..

Originally in nemo, all items had an arrow, empty or otherwise. When you clicked the arrow, it would be updated to say 'empty' or would briefly say 'loading' before displaying the folder's children.

Adding monitors to the current directory's children could end up having huge performance/memory implications, plus issues with mounted remote folders (which might not be detected).

I've considered, and talked about going back to that old behavior - always arrows, because at least it would be consistent. To be honest at the time I didn't realize the potential issues here myself or I wouldn't have changed this to begin with.

ps. There's a bug fix for crashes when expanding out-of-date folders that hasn't made it live yet.

[kimimaru4000]

@mtwebster Thanks a lot for explaining the technical challenges! That provides a lot of valuable insight into this issue.

I also feel that keeping the arrows all the time is a better solution for now due to its consistency as you mentioned.

[BNIslander]

I have a quick "workaround" that may be acceptable for some:

• Drag the folder in question to a neighbouring folder
• Press Ctrl-Z to undo the move - the folder will now have its arrow to allow it to be expanded.
  In this way the tree structure is not collapsed as would be the case with a "refresh" operation.

[lv2eof]

The @BNIslander "workaround" is a bit tricky but it works.
I'll use it till someone fix the bug another way because it also annoys me a lot.

[gaellafond]

The @BNIslander "workaround" is a bit tricky but it works. I'll use it till someone fix the bug another way because it also annoys me a lot.

I totally agree with you.

I have a edge case where I can't move the folder as suggested. The folder is auto-generated by an app I'm developing. The creation of all the files in the folder take about 10 minutes. If I move the folder half way through, the app will crash since its output folder will cease to exists. I need to see the files as they are getting generated to know if it's progressing well and to know when something goes wrong.

The only workaround that works for me is pressing F5, but that's just another annoyance. The generated folder tree structure is about 10 folder deep (the app generates a LOT of files). Pressing F5 close the whole tree structure and I have to navigate again to the folder I was looking at. That gives me headaches...

Just to add some context, the app I'm developing is generating videos from raw NetCDF data files. First step is to generate the video frames (images). Then it combines the frames to create a video. The raw data file contains a multi-dimensional array of data (longitude, latitude, depth, time, hundreds of variable). The large tree structure is necessary to separate the video frames by depth, time range and variables.

This is obviously an edge case, but that issue also annoys me every day, whatever I'm doing. Except the F5 trick works for me most of the time. It's just in that edge case where there is no acceptable workaround.

[lv2eof]

@gaellafond
Yes, your case it's a bit on the edge.
Nevertheless I think that as it is now, the Nemo behaviour is incorrect.
The optimum would be no arrow when the forder is empty and a arrow when something enters the folder.
Anyway I agree that this solution can carry some development issues.
So any of the other proposed solutions would be better than the one we have now.
But we have to wait till someone addresses the problem :-(