Document that when specifying text format you must specify value

Yes, it would seem that the unqualified form causes the entire field array to be written by that mapping. One might hope that it would somehow "know" what the primary value is and only write that specific value, but the Row class where this is happening knows nothing of field structures. We may need to simply document that when migrating multiple subvalues of a field, the primary value's subfield must be explicitly mapped.

I'm all for improving the documentation and this looks straightforward. Though, I'd prefer to have agreement before I change it. (Don't want to get it wrong and confuse folks.)

So, I reckon the information can go on Migrate process right after "Handling multiple values".

-- start example documentation --
Handling multiple subvalues of a field

The primary value of a field and all the subfields must be explicitly mapped. The following example uses the default_value plugin to map the format subfield.

  'field_name/value':
  'field_name/format':
    plugin: default_value
    default_value: 'full_html'

-- end example documentation --

Have added the comment for the same. Please review it.

Sorry attached the same patch file twice by mistake.

Firstly thanks for your contribution, @prash_98 - welcome to Drupal!

I'm afraid I doubt this is where @mikeryan and @quietone intended for the documentation to appear. Out of interest, why did you choose this file?

But before I'd even noticed that, I had a few points of feedback:

1. There is a typo and/or a repeated word (depending on which patch you read!):
   + * Along with thw the text also specify the text value.
+ * Along with the the text also specify the text value.
2. Comments do not require a new line until they reach 80 characters.
3. Comments should (noramlly) begin with a capital letter (you did this - great) and end with a full stop / period .

Thanks and would surely keep this in mind for the issues ahead.

@prash_98

Make the changes accordingly in the correct file and then upload the patch.

1. Removed @file.
2. Corrected comment.

Helps if I add the files too!

Assigning to myself for review.

The place for this documentation seems strange, as noted in #11. Let's move this either into the yml file for formats.

Added the documentation suggested by @quietone in #4:
https://www.drupal.org/docs/8/api/migrate-api/migrate-process-plugins/mi...

So, does #21 fix this? Or do we need to add a patch to change some doc block?

I've gone back and forth on this for the last wee while. Finally decided that it is a bit of a gotcha so it is better to add some documentation to processRow() about the consequences of $row->setDestinationProperty($destination, $value);

While can figure out the "main" propery value (see FieldItemInterface::mainPropertyName), that main property isn't used for base fields. It seems too much work to figure out the difference. This seems like a docs only fix. Probably could live on the d.o. documentation page about working with process plugins and how nested values function.

Tagging.

Based on #25, this is handbook documentation fix only.

I checked our handbook and it covers this info, see https://www.drupal.org/docs/8/api/migrate-api/migrate-process-plugins/mi...

Closing this as outdated. If someone feels that something else should be done under this issue, please re-open and specify the proposed actionable next steps.

Cheers,
Markus

For cases (such as XML files) where there may be zero, one or multiple value fields to be imported from the selector, the documented solutions don't work.

#3586125: Add text_format process plugin for setting text format on multi-value fields supports any number of input fields, preserving the input format for each of them.