Removing Final Element in YAML Array Inconsistent Behaviour

[itsonlyjames]

Steps to reproduce

Have YAML like so:

---
tags:
  - testing
aliases:
  - testing
---

Then via the UI properties editor, delete either tag or alias, and you’ll see it change to tags: [] or aliases: []

---
tags:
  - testing
aliases: []
---

Interacting then with the Properties UI alters the last appended empty array and removes the brackets, then again after another interaction.

---
tags: []
aliases: 
---

Did you follow the troubleshooting guide? Y

Expected result

It should simply remove the tag or alias and leave the area after the colon empty, returning tags: or aliases:

Actual result

Returns tags: [] or aliases: [] on final deletion

Environment

SYSTEM INFO:
Obsidian version: v1.6.5
Installer version: v1.6.3
Operating system: Darwin Kernel Version 24.0.0: Wed Jul 31 21:50:55 PDT 2024; root:xnu-11215.0.199.501.2~1/RELEASE_ARM64_T6020 24.0.0
Login status: not logged in
Insider build toggle: off
Live preview: on
Base theme: adapt to system
Community theme: none
Snippets enabled: 0
Restricted mode: on

RECOMMENDATIONS:
none

[WhiteNoise]

Please try to search before posting

YAML: Empty multi-line array gets formatted into ambiguous format after properties edit

Steps to reproduce foo: - val bar: - Add a second value to foo to cause Obsidian to format the front matter. bar get converted from a multi-line array into an ambiguous blank format, i.e. bar:, when at the very least it should be bar: [] (as when removing the final value of an array, see below). Did you follow the troubleshooting guide? Y Given the YAML example above, if instead you remove foo’s value, bar will experience the same as noted above, but foo, another multi-line array, resu…

[itsonlyjames]

You see, I did actually find that, and if you considered my bug in seldom , it’s completely different. That topic is suggesting lists should stay as bar: [], whereas my issue, which is completely different, asks why it changes on interaction from that empty array to a null value?

Sure, the value may still be an array, but say I delete the last element, and don’t interact with the Properties UI, then it’s stuck as tags: [] until I interact again. This is seemingly a bug.

Semantics aside, why is it inconsistent? What is the technical reason for this?

Please reinstate as a bug. This is different to the linked bug—which is in the graveyard and not to be fixed anyway.

[WhiteNoise]

The technical reason is that we process the YAML section internally (serialize, process, and deserialize it). You should not have the expectation that YAML stays the way you write it.

[itsonlyjames]

This is not related to the way I write it—you’ll notice it is entirely altered through the Properties UI.

Given your information, I consider this a bug within the processing process. It should go instantly to a null value—rather than first to an empty array, and then to a null value on subsequent interaction. I do not expect it to stay the way I write it. I do however, expect the behaviour to be consistent.

Why should it go go to an empty array and then a null value? It’s almost like it’s processing empty values at the wrong step in the interaction process.

[WhiteNoise]

As explained in the thread linked above, internally there is no difference between the two. There are no negative consequences with either format.

Feel free to open a feature request if you feel strongly there should be only one format.