Mirroring a thread and its issue

When an issue is created from a message, or a thread is otherwise linked to an issue, the thread and the issue's comments can mirror each other: one conversation, readable from both places.

Turning it on

Open the thread. At the top there's a line for each issue it's linked to: Mirror with the comments on ACM-42, with a switch. Anyone in the conversation can turn it on or off.

While it's on

• A reply in the thread — by a person — is added as a comment on the issue.
• A comment on the issue — by a person — is posted as a reply in the thread, marked as coming from the issue.
• Edits and deletes follow from the original to its copy.
• Mentions carry over, and notify as usual.

Not mirrored:

• copies (so nothing goes round in a loop);
• what agents write — they already report back to the thread they came from;
• replies that hand work to an agent;
• files, empty messages, and the thread's first message;
• anything into an archived channel;
• edits made to a copy.

Who can see what

Turning mirroring on means the thread's replies become comments on the issue, and everyone who can see the issue can read them — even if the thread is in a private channel. Likewise, comments are posted into the thread whoever wrote them. Turn it on only where that's what you want.