flagsmith fix: save feature error handling

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Changes

Tracks and displays errors when saving a feature.

How did you test this code?

Created a feature with a duplicate name
Attempted to save a feature whilst offline

May 30 '24 14:05 kyle-ssg

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May 30 '24 14:05 vercel[bot]

Uffizzi Preview deployment-53952 was deleted.

May 30 '24 14:05 github-actions[bot]

I'm still able to reproduce https://github.com/Flagsmith/flagsmith/issues/4025 on this preview environment:

https://github.com/Flagsmith/flagsmith/assets/829698/ad625a1e-abb9-45b7-afad-65dbac56b2a2

(#4025 is about the 404 error, this issue is about the error not being displayed and the save button not being re-enabled after an error)

May 30 '24 15:05 rolodato

Thats just because the PR doesnt have the latest main, the PRs were all up at the same time.

The preview url will now contain the other changes from yesterday.

May 31 '24 08:05 kyle-ssg

@rolodato This can be re-tested

Jun 04 '24 07:06 kyle-ssg

Tested again, this works:

Creating a feature with a duplicate name
Updating a feature twice on a versioning v2 environment, without closing the modal

This doesn't work:

Creating a feature while offline - no error message is shown and the Create button is never re-enabled
Updating a feature while offline - same as above

https://github.com/Flagsmith/flagsmith/assets/829698/e17729f6-0ab4-4a12-92e4-e20c76d89756

Jun 04 '24 20:06 rolodato

@rolodato can I just check you're testing on the right url ? Strangely the url in your video doesn't have the branch name in it.

Failing that, I suppose it could be that your browser is retrying/trying to connect the request whilst offline in which case I can't intercept it.

Regardless, here's what I'm seeing on the above.

https://github.com/Flagsmith/flagsmith/assets/8608314/00b5da8b-649f-4415-b061-af6ce8a0d61b

Jun 19 '24 15:06 kyle-ssg

@kyle-ssg I tried visiting the preview URL from your video (https://flagsmith-frontend-preview-git-fix-save-featur-1e23c8-flagsmith.vercel.app) and I still get the same behaviour when trying to create a feature in Firefox with "Work Offline" enabled, or in Chromium when setting the devtools Network throttling mode to "Offline". I see the same ERR_INTERNET_DISCONNECTED errors as you, but in my case no error is shown in the UI and the "Create Feature" or "Update Feature" buttons are never re-enabled.

Digging deeper I've found why this is working for you - you're trying to update a feature in a versioning-v1 environment. This also shows an error for me as expected. However, these all fail with no error message and the buttons are never re-enabled:

Create a feature in a v1 environment
Create a feature in a v2 environment
Update a feature in a v2 environment

Hopefully this video makes it clearer:

https://github.com/Flagsmith/flagsmith/assets/829698/34d180a0-4f12-4be4-9aed-81b4670c3c75

Jun 21 '24 18:06 rolodato

@kyle-ssg were you able to take a look at my comment above?

Jul 08 '24 11:07 rolodato

flagsmith image build and security scan finished :sparkles:

Image	Build Status	Security report
`ghcr.io/flagsmith/flagsmith:pr-4058`	Finished :white_check_mark:	Results :white_check_mark: