The "post_redirect" items of a source, each post's old address, written as the CMS's own redirect rules (MishkaCmsCore.Runtime.Redirect), through the :create and :update an admin's own redirect form runs, on the run's site and as the admin who pressed Import: the admin needs the core's admin:dashboard:runtime:redirect, and the core's own rules decide the rest, such as how an address is stored and that one site redirects an address once.

An item's "from" is the address the post had at the source, such as /2025/12/hello/, and the rule sends it, with a 301, to where the Blog serves the post the same run or an earlier one wrote for that source id (MishkaCmsMigration.Targets.BlogPost.address/3): /blog/hello for a post in the language the site leads with, /fa/blog/salam for one in Persian.

Which items

By the run's post_address choice (MishkaCmsMigration.MigrationRun's options), read with existing/2 before anything is written, in the dry run too:

• "blog_without_redirects" — every item is skipped as "not_chosen", and no rule is written;
• "blog" (the default) — a rule is written for each item, except:
  • one the source gives no old address ("from" is nil, such as a draft's) — skipped as "no_old_address";
  • in an import, one whose post has no Blog post — it failed, was never written or an admin left it out — skipped as "post_missing";
  • in an import, one whose old address is the post's Blog address already — skipped as "same_address".

A dry run writes no post, so it does not look for one: an item it plans may still be skipped for its post when the import runs.

An old address the site already redirects, by a rule of an admin's own or of another source's run, is refused by the core's one-rule-per-address identity, and the item fails with the core's reason; the site's rule is kept as it is.

A re-run is held to the rules every target is: a rule WordPress did not change is "unchanged", and one an admin edited or deleted in the CMS is kept as the admin left it (MishkaCmsMigration.Workers.Helpers.Decision). Switching the choice off later leaves the rules an earlier run wrote.

Defined only where Mishka Blog is loaded, and supervised by MishkaCmsMigration.Application only then; on a node without the Blog its items wait for it ("blog_missing").