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Classify recipients of a delivery status report: action normalization · case 03

A capitalised or padded action field is classified as unknown.

Member previewVariant 3 · 3 implementations · 7 checks per implementation

Case contract

A report is valid only when its type is multipart/report, its report-type parameter (name and value case-insensitive) is delivery-status, and its second part is message/delivery-status or message/global-delivery-status. Each recipient {final, action, status} gets: failed -> hard for status class 5, soft for 4, unknown otherwise; delayed -> delayed; delivered, relayed or expanded -> ok; anything else unknown (actions are case-insensitive and trimmed). has_original is true when a third part is message/rfc822 or text/rfc822-headers. Invalid reports give {valid False, recipients [], has_original False}.

Why this case matters

Bounce processing drives list hygiene and retry decisions; misclassification unsubscribes healthy addresses.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
padded capitalised action	`{"has_original": true, "recipients": [["e@x", "unknown"]], "valid": true}`	`{"has_original": true, "recipients": [["e@x", "hard"]], "valid": true}`	Failed

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