Mailspring shows wrong Subject

$ mailspring --version

$ uname -a
Linux fsx1tablet 4.19.0-9-amd64 #1 SMP Debian 4.19.118-2+deb10u1 (2020-06-07) x86_64 GNU/Linux

The following Email (mail addresses removed) is shown with Subject “test-from-” in Mailspring

MIME-Version: 1.0
Date: Thu, 30 Jul 2020 17:01:22 +0200
Subject: test-from-webclient
From: XXX
Content-Type: multipart/alternative; boundary=“0000000000001dfd4b05aba9f29c”

Content-Type: text/plain; charset=“UTF-8”

Content-Type: text/html; charset=“UTF-8”


Subject: abc-def-ghi
is shown as empty subject

(Originally posted by falko-strenzke on GitHub.)

Hey thanks for reporting this! Could you attach screenshot of where you’re seeing the subject line? I’m guessing this is actually a text truncation issue in the front-end rather than a sync problem. (It seems like Mailspring might be wrapping the text at the - characters?) Could you also verify that it happens with the stock theme if you’re using one of the custom ones? Cheers!

(Originally posted by bengotow on GitHub.)

I’m seeing this, too, but only in emails from me to myself. There may be some kind of race condition because it will often, but not always, occur. I only have Gmail so I have not tested this with other email providers.


  1. Use a different client (e.g., Gmail mobile app or Gmail website) to begin composing an email to yourself.
  2. In the subject line, type: 12345678
  3. Backspace over half of the numbers until the subject line reads: 1234
  4. Type the last four numbers again until the subject line reads: 12345678
  5. Send

At this point, Mailspring will receive the new email from you to yourself, but the subject line in the Mailspring UI (both in the inbox and the message view) will likely (but not always) say 1234 instead of 12345678. Displaying the original message shows the correct subject, 12345678.

The more I look at it, the more it seems like some kind of syncing issue due to Mailspring somehow getting confused about me sending email to myself with Gmail constantly syncing my draft updates to the server.

I followed my reproduction steps above using the Gmail web interface. This time, I didn’t get “1234” but simply “No subject”. This is what my Mailspring inbox looked like after I sent the email:


Interestingly, there are a bunch of draft emails in the thread.


(Originally posted by jfredrickson on GitHub.)

I am seeing the same behavior with an email very similar in content that I have sent to two different people. One person replied but it shows the subject line of the other conversation.

It MAY have to do with the pattern matching done to group emails into conversations. I have posted a bug report but haven’t gotten a reply. I have specifically said that I’m sure I could fix this by myself but again, I need someone to tell me where that matching logic sits as it appears to be undocumented.

(Originally posted by Reiszecke on GitHub.)