FA-76574 / Email MIME structure / Member archive

Choose the MIME skeleton for an outgoing message: related root first · case 04

The HTML root is placed after the images inside multipart/related.

Member previewVariant 4 · 3 implementations · 7 checks per implementation

Case contract

The body is multipart/alternative(text, html) when both versions exist, the html alone when only html exists, else text. Inline images go into multipart/related with the html root first; without html they become attachments. When there are attachments the result is multipart/mixed(body, attachments...). Output is a compact string such as "mixed(alternative(text,related(html,img)),att)".

Why this case matters

Composing the wrong skeleton makes clients show images as attachments, hide the plain-text version or drop parts.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
text html and images	`"alternative(text,related(img,img,img,img,img,html))"`	`"alternative(text,related(html,img,img,img,img,img))"`	Failed

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