Right To Left (RTL) language (Hebrew) messages are left-aligned instead of right

[oriregev]

Using a supported version?

• I have searched open and closed issues for duplicates.
• I am using Signal-Desktop as provided by the Signal team, not a 3rd-party package.

Overall summary

Messages that were written in Right To Left (RTL) language (Hebrew) are displayed aligned to the left instead of to the right. Mixing RTL text (Heberw) with LTR text in the same message makes things even worse.
Note that this was working fine until the last update to version 8.6.0
Note also that the text is displayed correctly in the text field, until you click "Send".

Steps to reproduce

Scenario 1 (RTL text):

1. Write a message in Hebrew
2. Click "Send"
3. The message is displayed incorrectly

Scenario 2 (RTL and LTR text):

1. Write a message that mixes Hebrew and English
2. Click "Send"
3. The message is displayed incorrectly

Expected result

A message in RTL (Hebrew) should be right-aligned.
A message that starts in Hebrew and includes words in English should maintain it's correct flow and the whole message should be right-aligned

Actual result

1. Messages in Hebrew should be displayed aligned to the right.
2. Messages the mix Hebrew and English should maintain the original flow from right to left.
3. Note also that the text is displayed correctly in the text field, until you click "Send".

Screenshots

Note also that the text is displayed correctly in the text field, until you click "Send".

Signal version

8.6.0

Operating system

macOS Tahoe 26.4 (25E246)

Version of Signal on your phone

8.5 (1491)

Link to debug log

No response

[marcos-morar]

This bug was reported on the very same day that version 8.6 was released. The fix was committed the same day, but it still hasn’t been approved. It looks like the Signal team has no intention of fixing this bug in the upcoming release.

[dannykhen]

I am seeing the same behavior in v8.6.0. I would say that the worst part of the issue is that, while the message is rendered left-aligned (should be right-aligned), the Signal markup (time and read receipt) is also rendered on the left (as it should be), which means that the message text and markup overlap, making some of the text entirely unreadable, not just garbled. This can be clearly seen in @oriregev 's screenshot.

The bug repros consistently in all RTL/mixed messages, so it affects a very large population (Arabic alone is estimated at 400 million speakers, with the entire RTL population somewhere between 500 million and 1 billion).

For these reasons, I urge the Signal team to prioritize deploying the fix without delay.
Thanks!

[nehemiagurl]

turns out punctuation is also suffering from the same misalignment. interestingly enough this bug is only in the messages themselves, other fields behave fine.

[dannykhen]

That's a side effect of rendering bi-directional text the wrong way. Text is broken down into RTL and LTR chunks, and they are rendered in order in the main direction (LTR in this case, instead of RTL). Punctuation embedded within a chunk is considered as being part of the chunk and gets rendered in place correctly; punctuation not embedded within a chunk is considered it's own chunk and rendered in the main order. In the example above, if you added even one more Hebrew letter after the exclamation marks, the whole thing would have been rendered correctly (but still left-adjusted).

The main / only bug here is failing to recognize that the message should be rendered RTL (which is typically when it either contains only RTL letters, or mixed but starts with RTL letters).

[dannykhen]

I guess the difference between the message input field and the rendered messages is simply different components behaving in different ways. This is convenient because the input field behaves spot-on and can be used to verify the different cases.

[ayumi-signal]

Really sorry for this issue! We've released 8.6.1 and 8.7.0-beta.2 with fixes for RTL languages.

[dannykhen]

Wonderful! I can confirm no repro in v8.6.1.
Much appreciated!