Diff module not tracking fields that existed before module was installed

Question

I have a Drupal project in the final stages of development. It has quite a lot of content types and a lot of fields. I have recently enabled revisions and added the diff module (7.x-3.2). It isn't tracking changes on my existing fields. When I choose 'compare' it shows 'No visible changes' and the current revision area only shows the new fields.

If I add a new field diff starts working on it. If I remove a field and re-add it diff starts working on the new version of the field. Any idea why this is happening? Are there any ways I can get diff working on all my fields without removing an re-adding all of them?

I tried editing and saving a field without making any changes to it, but this did not make diff tracking start working on it. I have looked in the DB and both a field being tracked and a field that isn't being tracked have a revision_id.

I have tested in a sandbox server and the diff module works as expected. Therefore it must be a conflict or a bug that is being triggered by my install.

Answer 1

Did you read the README for the module and go through the module configuration? See CONFIGURATION section of the readme.

2) Field revisioning settings

   Global settings per field type can be found here:

   http://www.example.com/admin/config/content/diff/fields

   "Show field title" toggles field title visibility on the comparison page.

   "Markdown callback" is the callback used to render the field when viewing the
   page in the "Marked down" page view.

   "Line counter" is an optional. This shows the approximate line number where
   the change occurred. This is an approximate counter only.

   Other fields add additional settings here.

This Diff Issue Queue item describes a similar "No visible changes." problem encountered by another user.

From the issue it sounds like the diff comparison view, which is typically "Standard comparision preview" settings == "Full content" needs to be configured to show the fields you want, or be the correct view_mode for the content.