[freedomcomedelivery]

Summary

Editing the caption of an image/video/document message in a newsletter (channel) fails with server returned error 479, while editing a text message in the same newsletter works. This is the root cause behind devlikeapro/waha#1852 ("[GOWS] - Edit message with image not working in Channels") and the same symptom as tulir/whatsmeow discussion tulir#697.

Root cause

In sendNewsletter() the node type attribute is computed from the outer EditedMessage wrapper before the edited content is unwrapped into the <plaintext> node. getTypeFromMessage() has no case for EditedMessage, so the wrapper falls through to "text". A media caption edit therefore goes out as

<message to=... type="text" edit="3">
  <plaintext mediatype="image">…ImageMessage{caption: …}…</plaintext>
</message>

whereas the original media send is type="media". In 1:1 chats and groups this mismatch is invisible (the content is encrypted), but a newsletter message is plaintext and the server rejects the mismatch with 479.

Fix

Recompute attrs["type"] from the unwrapped edited content. Text edits are unaffected (their type is "text" either way); media caption edits now go out as type="media", exactly like the original send.

What was tried and did not help

Before finding the cause I checked the two obvious suspects, both still returned 479:

• sending the edited ImageMessage/VideoMessage with the full media reference of the original (URL, directPath, fileSha256, fileLength, …) instead of caption + contextInfo only;
• re-uploading the media with UploadNewsletter and passing the new handle as SendRequestExtra.MediaHandle (media_id attribute), as suggested in discussion Editing Newsletter Caption (ImageMessage) returns 479 tulir/whatsmeow#697.

Neither is needed. With this change the caption-only edited message (as built by WAHA/GOWS today) is accepted.

Testing

Built GOWS (gows-plus @ 120a614, the commit behind the WAHA 2026.9.2 image) against this fork at the pinned commit plus this patch, and ran it as the engine of WAHA 2026.9.2 (devlikeapro/waha:gows-2026.9.2) with a real WhatsApp account that is an admin of a newsletter:

• PUT /api/{session}/chats/{chatId}/messages/{id} on an image message → 200, the new caption is shown in the channel on the phone;
• the same on a video message → 200, the new caption is shown;
• the same on a text message → 200 (regression check);
• a second edit of the same image message → 200.

Without the patch every media edit above fails with 2 UNKNOWN: server returned error 479.

Notes

• The same code exists in upstream tulir/whatsmeow (send.go, sendNewsletter); I have the identical change ready for an upstream PR.
• gofmt, go build ./... and go vet are clean.