[rizvee]

Summary

Fixes #15806 by preventing unwanted whitespace padding inside square brackets, quotes, and backticks.

This preserves Markdown task lists such as "- [ ] item" without inserting an extra space.

Changes

• Restrict automatic whitespace padding to parentheses and braces.
• Preserve existing behavior for "()" and "{}".
• Add focused regression tests covering brackets, single/double quotes, backticks, parentheses, and braces.

Scope and verification

• One changed file: "helix-core/src/auto_pairs.rs".
• Based directly on the latest upstream "master".
• No unrelated LSP, transaction, or Windows build changes.
• Regression tests added; CI results pending.

Split from #15976 following maintainer feedback to isolate independent fixes.

Closes #15806.

[woojiq]

@dead10ck are you ok with these changes?

[dead10ck]

Narrowing the set of pairs for which an extra whitespace is added does make sense, but I think this calls for a more general solution.

By and large, I think there are some pairs it doesn't really make sense to add the extra whitespace, such as quotation marks, but others really depend on the particular language. Square brackets were a primary use case for adding this feature to begin with, to pad list literals; but for some languages, like markdown, this is less likely to be desirable.

I think it would make more sense to add another config option to choose which pairs will pad whitespace. Similar to editor.auto-pairs, there could be an editor.whitespace-pairs with a list of opening chars which should pad whitespace, and a corresponding language-specific config to override the global.

For example,

# config.toml
[editor]
whitespace-pairs = [
  '(',
  '{',
  '[',
]

# languages.toml
[[language]]
name = "markdown"

[language.whitespace-pairs]
whitespace-pairs = [
  '(',
  '{',
]

With this config, the default set of pairs would be all brackets, but Markdown would omit [].

For consistency, it could also accept a boolean to turn off the feature completely.

# config.toml
[editor]
whitespace-pairs = [
  '(',
  '{',
  '[',
]

# languages.toml
[[language]]
name = "markdown"

[language.whitespace-pairs]
whitespace-pairs = false

This would disable whitespace padding only for markdown.

Similarly, setting the global setting to false would disable the feature regardless of language settings.

# config.toml
[editor]
whitespace-pairs = false

# languages.toml
[[language]]
name = "markdown"

[language.whitespace-pairs]
whitespace-pairs = [
  '(',
  '{',
]

This would disable whitespace padding regardless of the markdown config.

@archseer @the-mikedavis @pascalkuthe what do you guys think?