Faulty recognition of closing sequence in atx headers - Githubissues

jrblevin / markdown-mode

Emacs Markdown Mode

http://jblevins.org/projects/markdown-mode/

GNU General Public License v3.0

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Faulty recognition of closing sequence in atx headers #778

Closed kuranari closed 11 months ago

kuranari commented 12 months ago

Expected Behavior

We want trailing spaces to be visible when markdown-hide-markup is enabled.
- The current behavior results in an unnatural input experience(see the attached video for more details).
The closing sequence must be preceded by a space or tab
- According to the Common Mark specification: https://spec.commonmark.org/0.30/#example-75

Actual Behavior

Trailing spaces are not visible when 'markdown-hide-markup' is enabled.
A closing sequence is identified even without a trailing whitespace.

Steps to Reproduce

Input # foo# or ## Steps to Reproduce

https://github.com/jrblevin/markdown-mode/assets/2577343/c7733f4a-7ff5-4952-833a-25ebe84059c0

The whitespace appears when the next character is entered.

Software Versions

Markdown Mode: 2.6-alpha
Emacs: GNU Emacs 28.2
OS: macOS Ventura 13.3.1 (a)

Additional Details

The issue occurs due to the definition of markdown-regex-header.

Changes were introduced to align with the implementation of Markdown.pl as per this commit: https://github.com/jrblevin/markdown-mode/commit/26e39378e0fd4445bd8409ef72a7ffbf322293bc

While the behavior of the whitespace following the opening sequence was modified with this commit: https://github.com/jrblevin/markdown-mode/commit/58ba6a31843a3dc919aece5f3a152067af3d3ff5, the behavior of the whitespace preceding the closing sequence was not altered.