Updated PNG file disappears from Nemo when edited while still opened in Xviewer

[SebastJava]

 * Nemo version 4.8.4
 * Issue with windowed nemo
 * Distribution Linux Mint Cinnamon 20.1
 * Device-1: Intel 2nd Generation Core Processor Family Integrated Graphics vendor: Dell driver: i915
 * 64 bit

Similar to #2623, #2621, #1922
This is part of a group of similar issues. Same disturbing results, but various different ways to get stuck... Here i am trying to make it very far from an edge case, and show this issue occurs with very regular, newbie, simple common stuff... I am just modifying a simple PNG image, using popular software such as the simple Drawing or the complex GIMP, and... boom! My image disappeared!

Steps to reproduce

NOTES:

1. MAKE SURE YOU NEVER CLOSE NEMO OR ANY NEMO WINDOW during all the following steps.
2. (UNNECESSARY?) IF YOU TRY THIS MORE THAN ONCE, maybe you should make sure you never put the same filename. This to avoid any possible cache memory trick? I am not sure this is necessary, but i take the extra precaution to name my new files with the current time, without using spaces or weird characters. Example: circle-21-01-08-15-16.svg
3. Please do the following file operations using only Nemo GUI. Think like an artist. Keep it simple.
4. Prefer using the Drawing application for this test. Drawing ships standard with the new Mint 20.x. This bug was reproduced on both Drawing app and GIMP app, but GIMP is more complex as you have to export to PNG file format...

OPERATIONS:

1. Create a new directory: ~/test-XX
2. There, create some PNG image using the standard Drawing application (included in the new Mint 20.x), or GIMP, or whatever image editing software for PNG images. Save this PNG (or Export to PNG) in your new test directory: ~/test-XX/image-YY-MM-DD-HH-MM.png
3. Just take a look at this new PNG file’s icon in this test directory, in Nemo. Just to make sure a custom thumbnail was created: a small version of your actual image file.
4. Open this image-YY-MM-DD-HH-MM.png using the standard Cinnamon Image Viewer (Xviewer 2.6.2). LEAVE IT OPENED AND VISIBLE on your desktop from now on...
5. Change directory: go to the parent folder so you don’t see the contents in this ~/test-XX folder, WITHOUT CLOSING this Nemo window.
6. Still using Drawing or GIMP or whatever, change something in this image-YY-MM-DD-HH-MM.png and save it (or Export to PNG). I mean, just "Save" to the same file, or Export and replace the same file...
7. Take a look at your Xviewer window that you had left opened on your desktop... See? Xviewer is smart enough to update automatically!
8. Re-open ~/test-XX directory now... What!? The PNG file is not displayed, like it is lost or something, and Nemo keeps displaying an endless spinning «Loading...» indicator. See my screenshot here.

Of course, closing and re-opening this ~/test-XX directory solves this little bug, but it can get quite disturbing as it happens all the time in those generic, casual, simple daily life stuff...

Expected behaviour
I would expect to see a custom thumbnail showing a small preview of my image. Or at least some generic icon. Or at least something, so i don’t panic and think my file is lost!

[SebastJava]

Tested with Drawing (included in Mint 20.x) and re-tested with GIMP !

[icarter09]

@SebastJava what is different between this ticket and #2623 and #2621 ?

[icarter09]

Nemo 4.8.4
Mint 20.1 64bit

I'm not able to reproduce this issue. I'm editing a PNG file via Pix with Nemo open. Every change I make to the PNG file, I see it updated and reflected in the open Nemo window.

[Jeremy7701]

I can reproduce this (with a JPEG file in pix).
Note - step 5 is crucial!

[icarter09]

I'm going to close this ticket since since it's a duplicate of #2623

[SebastJava]

@icarter09 :

SebastJava what is different between this ticket and #2623 and #2621 ?

My answer is in the introduction on top of this current page:
This is part of a group of similar issues. Same disturbing results, but various different ways to get stuck... Here i am trying to make it very far from an edge case, and show this issue occurs with very regular, newbie, simple common stuff... I am just modifying a simple PNG image, using popular software such as the simple Drawing or the complex GIMP, and... boom! My image disappeared!

Also, it just adds more information, and thus, possibly, more clues, and a larger view. And the amount of similar issues shows there are many situations where this bothering and frightening file disappearance can occur. Anyway, the links to all these similar issues are still there in #2623 and #2621...

[SebastJava]

@icarter09 :

SebastJava what is different between this ticket and #2623 and #2621 ?

Also, i changed the title here to make it clearer:
Updated PNG file disappears from Nemo when edited while still opened in Xviewer

Same results, yes, but different ways to get into this...

[Jeremy7701]

In all of these examples you appear to be creating, deleting and re-creating the same filename in a sub-folder of a single nemo view.
Would leaving an extra nemo window open at the relevant sub-folder prevent this issue showing itself?

[SebastJava]

@Jeremy7701
@mtwebster (i am responding to Jeremy but i thought you could find this interesting too...)
It is getting late here and i am afraid i could make mistakes... But i couldn’t resist and so i did make some little quick tests past midnight, now.

1. First of all, you are talking about a sub-folder. This refers to issue SVG and PNG files "disappears" after editing a copy of it. Endless "Loading" cycling indicator is displayed... #2623, not this one here. This page is about issue 2628 but all or almost all of this post will be about issue SVG and PNG files "disappears" after editing a copy of it. Endless "Loading" cycling indicator is displayed... #2623. More precisely, the top, first one in this SVG and PNG files "disappears" after editing a copy of it. Endless "Loading" cycling indicator is displayed... #2623.
2. "Creating, deleting and re-creating"? I don’t remember deleting anything. There was duplicating and changing and saving in SVG and PNG files "disappears" after editing a copy of it. Endless "Loading" cycling indicator is displayed... #2623, there was renaming and changing and saving in Thumbnails are not updated when editing SVG files after having renamed them #2621, there was a simple changing and saving while being still opened in Xviewer in Updated PNG file disappears from Nemo when edited while still opened in Xviewer #2628, but i don’t remember deleting anything.
3. While most of my instructions must be precisely followed, some things were just extra fancy stuff for fun. Like drawing a circle... That's not important, any shape would do of course. And this sub-folder, i am not sure that was really essential. The sub-folder is there just to help to write clear instructions. To ensure you move to a parent directory, so the icon is not visible in Nemo, but without closing the window. But i guess it would probably lead to same results if it was 2 different folders on the same hierarchy level, not a sub-folder. There are two folders there in SVG and PNG files "disappears" after editing a copy of it. Endless "Loading" cycling indicator is displayed... #2623 just because we are talking about making a duplicate, but with the same name. Hey, maybe it could be "drawing (copy).svg" in the same folder and you would still get that same bug? YES! I couldn’t resist and i tested it right now. I still get the same bug. See my screenshot here. There was one original and one copy in the same folder. The copy got updated while Nemo was in ~/sebastien, the parent directory. Now, in this screenshot, the original SVG is there, but the copy, changed and saved, is missing and there is an endless "Loading" cycling symbol. There are many ways to fall into this bug, i am not sure i tried them all!
4. THE KEY THING here and in SVG and PNG files "disappears" after editing a copy of it. Endless "Loading" cycling indicator is displayed... #2623, is that, at some point, the thumbnail being changed and saved is not visible in Nemo, but without closing the Nemo window. So, unsurprisingly, i re-played all the steps in top issue SVG and PNG files "disappears" after editing a copy of it. Endless "Loading" cycling indicator is displayed... #2623, but with "an extra nemo window open at the relevant sub-folder" as you were asking, and, yes, it did prevent this issue from showing itself.
5. THE REAL KEY THING is that you are not closing Nemo during all this time, to be more accurate. I did another test. A different one. I had circle-YY-MM-DD-HH-MM.svg and circle-YY-MM-DD-HH-MM (copy).svg in the same folder. This folder was opened, so i saw the thumbnails were generated, on both the original and the copy. Then I DID CLOSE THIS WINDOW, doing precisely what i was forbidding you to do! BUT, at the same time, the FileSystem window (/) was left opened, so i did not quit and restart Nemo at any time during all the operations... Now, when the test window was closed (but Nemo was still opened!), i changed the color in my duplicated SVG. I wanted a new color, but i could have done any other change. Next, i saved it. Next, i re-opened the test directory... As expected, the bug was still there! As expected, the original, unchanged SVG was displayed correctly, with a nice thumbnail displaying a small preview of the real image. And... as expected, the re-edited copy was missing, apparently lost, and Nemo was, apparently, stucked on trying to load something! See my screenshot here:

Please take note that it took me a lot of time just to remember and replay all or some of my little nightmares i had during 2020 but never had time to report until now. I am sure you will have a lot of fun too! Bonus: i guess if you succeed in solving one of these issues, all of them will be solved, since they are all similar. Remember, there are #2623, #2628, #2621, and #1922. They are all similar, but not the same! I dropped TONS of information here. Enjoy! :)

[SebastJava]

SOLVED!
Re-tested twice following my standard steps to reproduce on top of this page. On the latest Nemo, version 4.8.5. All updates from 21-02-27 and 21-02-28 got applied. My system is up-to-date as of 21-03-01. It looks good. Thanks.