[wp-trac] [WordPress Trac] #44215: Personal data exports - Empty values are included in the report

[WordPress Trac]

#44215: Personal data exports - Empty values are included in the report
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 Reporter:  bor0                                 |       Owner:  (none)
     Type:  defect (bug)                         |      Status:  new
 Priority:  normal                               |   Milestone:  Awaiting
                                                 |  Review
Component:  Privacy                              |     Version:  4.9.6
 Severity:  normal                               |  Resolution:
 Keywords:  has-patch has-screenshots 2nd-       |     Focuses:
  opinion                                        |
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Changes (by desrosj):

 * keywords:  has-patch has-screenshots 2nd-opinion close => has-patch has-
     screenshots 2nd-opinion


Comment:

 Did some testing. Here are my findings of the current behaviors in core.

 The fields currently included in a data export are core user fields, a few
 core user meta fields, and core comment fields. All of these are either
 varchars, int/bigints, or text types.

 - Passing `false` as a meta value results in an empty string being stored.
 - Passing a `0` integer as a meta value results in a `0` string being
 stored.

 All values for these fields are passed through `if ( ! empty( $value ) )`
 before adding the data to the export. This means that in the current
 state, any empty field (which indicates an absence of data) will always be
 removed from the export. This should probably be changed.

 If the meta key exists, it potentially means something and should be
 displayed in the export, even if empty. Users, for example, may have an
 empty description, last name, or nickname field. Comments may have an
 empty author URL or Author IP. It could be important for the user to know
 that those fields are present and are in fact empty.

 If a core user meta field has been deleted, a PHP notice is currently
 thrown. Example: A plugin deletes the `last_name` meta field for a user.
 When this happens, the field can be excluded from the report because it
 does not exist.

 Incoming patch with these changes.

 Worth noting, only the behavior in core's data exporters can be
 controlled. Plugins with custom data exporters will have their own logic
 about what to include and why. I think that the plugin handbook pages
 about creating data exporters should be updated to include a section about
 the differences between no data and empty data.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/44215#comment:12>
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