Delete media from the server when the event is redacted

[turt2live]

In theory if we do this right on the technical side then there won't be any client changes, however this is an important enough feature to need to point people at UI-wise. We might also want to add a checkbox or similar for "[ ] and all related media", so could argue it needs design 😇

This issue also doubles as a launching point if product/design wants to find a way to push it forward (alongside all other features and responsibilities, of course).

Technical links:

• When we redact events, any mxc content they refer to should be redacted too (SYN-216) matrix-org/synapse#1263
• There is no way to delete content from the media repo matrix-org/matrix-spec#226
• Links within the above to MSCs and other spec/impl issues

[waclaw66]

That takes into account the newly redacted messages when it's implemented, right? What about gigs of attachments that have been already redacted, but there is no reference (message source cannot be displayed) to it's mxc in the db?

[richvdh]

MSC3911 is a proposal to fix this