thunderbird / thunderbird/thunderbird-android

paperclip (attachment) icon for email with inline image

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#3,405 1 comment 2 reactions 0 assignees View on GitHub

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Dominant language
Kotlin
Stars
14k
Forks
2.8k
Avg merge
3d 3h
Merged PRs (30d)
57

Description

Expected behavior

No paperclip (attachment) icon because there is no real attachment.

Actual behavior

Paperclip icon appears in message list for an email with only inline images.

Steps to reproduce
  1. Create a HTML message with inline images.
  2. Send it to an email account.
  3. Check this account in K9 Mail client.
Environment

K-9 Mail version: 5.403

Android version: 6.0

Account type (IMAP, POP3, WebDAV/Exchange): IMAP

Sample email source below appears correctly in recent Thunderbird (52.7) and Gmail: no paperclip (attachment) icon there. K9 Mail incorrectly marks this email with paperclip.

Subject: paperclip icon example for inline image
Content-Type: multipart/alternative;
    boundary="boundary-for-multipart-alternative"
Content-Transfer-Encoding: 8bit

This is a multi-part message in MIME format.

--boundary-for-multipart-alternative
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

(plain text content)

--boundary-for-multipart-alternative
Content-Type: multipart/related;
    boundary="boundary-for-multipart-related"

--boundary-for-multipart-related
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: 8bit

<html>
  <head></head>
  <body>
      <img src="cid:k9mail"/>
      (html content)
  </body>
</html>


--boundary-for-multipart-related
Content-Type: image/png
Content-Transfer-Encoding: base64
Content-ID: <k9mail>
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--boundary-for-multipart-related--

--boundary-for-multipart-alternative--

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the issue with the sample MIME source and inspect how K-9 Mail classifies inline CID images when building the message-list paperclip indicator. Done means messages containing only inline images no longer show the attachment icon, while real attachments still do; the issue does not name a source file or test.

Written by the indexing model from the issue text.

Assessment

Tech stack
android, kotlin
Domain
mobile
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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