Warning: Undefined array key in CustomTableFormatter.php

Ahh, thanks for the report. I need to check for the setting before comparison of value in:

$is_hidden = $settings['fields'][$name]['format_type'] === 'hidden' ?? FALSE;

Thats an easy fix. I'll have a patch up shortly.

Cool, thanks! I forgot to add an important bit: "[...] if a field is empty", since it doesn't happen if all fields have values. (I added it in the Issue Summary)

I am honestly not able to reproduce this. It shouldn't even get to that point if $items is empty. Assuming this is a multi-valued field, it seems like one of your items is for some reason not being considered empty. Is it just a: string, uri, and string_long subfield structure?

What kind of entity is this field attached to or is it being used in layout builder or something?

Its a mystery to me how to get to the error but the patch should at least fix it if you can try out and report back please.

Could it be because it's a migration, and the fields are not set as NULL in the database? The fields are Text (long), URI and Integer, though it's hard to find a pattern ...

Anyway, the patch works perfectly, and I no longer get the warnings. Thanks!

I don't think thats the issue cause the loop was just going over the settings which is configuration but anyhow its fixed and merged. Thanks!

Strange, but awesome that it got fixed so fast, I really appreciate it!

I just tried replicating this with Custom Field 3.1.5 in a Drupal 11 installation (original issue in D10), also with DDEV PHP 8.3, and get the same warnings. Empty field or not makes no difference, like you write - it's a config thing.

These are the two config files:

field.field.node.article.field_journal.yml

uuid: 5a41cd90-8fe4-4554-bb9c-b2a14a45aa5a
langcode: en
status: true
dependencies:
  config:
    - field.storage.node.field_journal
    - node.type.article
  module:
    - custom_field
id: node.article.field_journal
field_name: field_journal
entity_type: node
bundle: article
label: Journal
description: ''
required: false
translatable: false
default_value: {  }
default_value_callback: ''
settings:
  add_more_label: ''
  field_settings:
    value:
      type: text
      weight: 0
      check_empty: false
      widget_settings:
        label: Name
        translatable: false
        settings:
          description: ''
          description_display: after
          size: 60
          placeholder: ''
          maxlength: 255
          maxlength_js: false
          prefix: ''
          suffix: ''
          required: false
    journal_comment:
      type: text
      weight: 0
      check_empty: false
      widget_settings:
        label: 'Journal comment'
        translatable: false
        settings:
          description: ''
          description_display: after
          size: 60
          placeholder: ''
          maxlength: 255
          maxlength_js: false
          prefix: ''
          suffix: ''
          required: false
    journal_link:
      type: url
      weight: 0
      check_empty: false
      widget_settings:
        label: 'Journal link'
        translatable: false
        settings:
          description: ''
          description_display: after
          size: 60
          placeholder: ''
          required: false
          link_type: 17
          field_prefix: default
          field_prefix_custom: ''
field_type: custom

field.storage.node.field_journal.yml

uuid: c6c261fe-853e-4f69-aba3-77311c275992
langcode: en
status: true
dependencies:
  module:
    - custom_field
    - node
id: node.field_journal
field_name: field_journal
entity_type: node
type: custom
settings:
  columns:
    value:
      name: value
      type: string
      max_length: '255'
      unsigned: 0
      precision: '10'
      scale: '2'
      size: normal
      datetime_type: datetime
    journal_comment:
      name: journal_comment
      type: string
      max_length: '255'
      unsigned: 0
      precision: '10'
      scale: '2'
      size: normal
      datetime_type: datetime
    journal_link:
      name: journal_link
      type: uri
      max_length: '255'
      unsigned: 0
      precision: '10'
      scale: '2'
      size: normal
      datetime_type: datetime
module: custom_field
locked: false
cardinality: 1
translatable: true
indexes: {  }
persist_with_no_fields: false
custom_storage: false