feat(markdown): add prettier tests for markdown formatter

[tidefield]

Summary

This PR adds the prettier tests to run against the snapshots added by #9067.

Test Plan

$ cargo test -p biome_markdown_formatter --test prettier_tests

Related #3718

[changeset-bot]

⚠️ No Changeset found

Latest commit: 7f71eb4

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[codspeed-hq]

Merging this PR will not alter performance

✅ 58 untouched benchmarks
⏩ 156 skipped benchmarks¹

---

_{Comparing tidefield:add-prettier-tests (7f71eb4) with main (3d0648f)}

Footnotes

1. 156 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[tidefield]

@ematipico given you already reviewed #9070 (review) and the PR overlaps with the plumbing I needed to do to get the tests running, feel free to defer reviewing my PR if you like.

We can also just merge this PR (if it's approved sooner) and rebase @jfmcdowell 's branch in the other branch. I'm happy either way.

[coderabbitai]

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Walkthrough

This PR introduces Markdown configuration support by creating a new markdown.rs module within biome_configuration that defines MarkdownConfiguration and MarkdownFormatterConfiguration structs. The configuration is wired into the central Configuration struct as an optional field. The Markdown formatter crate is updated with configuration-related dependencies and test harnesses. Builder methods are added to MarkdownFormatOptions for setting indentation and styling preferences. Test infrastructure for Markdown formatting is established, including Prettier-style snapshot tests.

Possibly related PRs

• feat(formatter): set up boiletplate for markdown formatter #8962: Adds foundational boilerplate and module structure for the Markdown formatter crate that this configuration PR builds upon.

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: adding Prettier tests for the markdown formatter, which aligns with the changeset.
Description check	✅ Passed	The description clearly explains the PR's purpose: adding Prettier tests to run against snapshots from PR #9067, with test commands and related issue reference.

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@crates/biome_markdown_formatter/src/context.rs`:
- Around line 112-115: The Display impl for MarkdownFormatOptions currently
calls todo!() which will panic at runtime; replace the todo with a minimal,
non-panicking implementation (e.g., accept the fmt::Formatter parameter name f
and call write!(f, "{:?}", self) or write!(f, "MarkdownFormatOptions")) so
formatting uses the existing Debug derive or a simple placeholder; update the
impl for fmt::Display for MarkdownFormatOptions to use f and write the output
instead of todo!().

🧹 Nitpick comments (2)

crates/biome_markdown_formatter/tests/spec_tests.rs (1)

3-9: Placeholder test suite — no specs will run yet.

The tests/specs/markdown/ directory doesn't exist, so gen_tests! will generate zero test functions. The TODO is noted, but it would be good to track this as an issue so it doesn't get forgotten.

Would you like me to open an issue to track adding the markdown spec test fixtures?

crates/biome_configuration/src/markdown.rs (1)

20-22: Unused type aliases.

MarkdownLinterEnabled, MarkdownAssistEnabled, and MarkdownParseInterpolation are defined but not referenced anywhere in this PR. They're presumably scaffolding for future work — consider adding a brief comment to that effect, or removing them until needed.

[ematipico]

@tidefield I see now. Yes, there's a bit of overlap but @jfmcdowell PR's add things that are missing here.

There's also the PRs target two different branches. Since we aren't enabling to the end user, it's safe to merge things in main.

My advice:

• change @jfmcdowell PR's target to point main
• address my review
• merge
• rebase this PR on top of the new changes

[coderabbitai]

Actionable comments posted: 3

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@crates/biome_configuration/src/lib.rs`:
- Line 38: The crate root currently imports MarkdownConfiguration and
markdown_configuration privately (use crate::markdown::{MarkdownConfiguration,
markdown_configuration}); change this to re-export them publicly so they follow
the same pattern as the other languages: replace the private import with a pub
use of MarkdownConfiguration and markdown_configuration at the crate root (i.e.,
add them to the existing pub use group alongside CssConfiguration,
GraphqlConfiguration, GritConfiguration, HtmlConfiguration, JsConfiguration,
JsonConfiguration) so downstream consumers can access
biome_configuration::MarkdownConfiguration and
biome_configuration::markdown_configuration directly.

In `@crates/biome_configuration/src/markdown.rs`:
- Line 24: Fix the grammar in the doc comment for the Options type: change the
phrase "Options that changes how the Markdown formatter behaves" to "Options
that change how the Markdown formatter behaves" (update the doc comment above
the Options definition in markdown.rs).
- Line 45: Update the doc comment "The size of the indentation applied to
Markdown files. Default to 2." to use correct grammar—change "Default to 2" to
"Defaults to 2"; this is the doc comment for the indentation field immediately
above the `line_width` field in markdown.rs so adjust that comment text
accordingly.

[coderabbitai]

🧹 Nitpick comments (2)

crates/biome_configuration/src/markdown.rs (2)

50-50: Nit: doc comment phrasing.

"What's the max width of a line" reads a bit colloquially for API docs. A minor tweak for consistency with typical biome doc style:

📝 Suggested wording

-    /// What's the max width of a line applied to Markdown files. Defaults to 80.
+    /// The max width of a line applied to Markdown files. Defaults to 80.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@crates/biome_configuration/src/markdown.rs` at line 50, Replace the
colloquial doc comment "What's the max width of a line applied to Markdown
files. Defaults to 80." with a more formal API-style wording such as "Maximum
line width for Markdown files. Defaults to 80." — update the doc comment
attached to the Markdown configuration field (the comment currently reading
"What's the max width of a line applied to Markdown files. Defaults to 80.") so
it uses the suggested phrasing for consistency with other biome docs.

---

19-22: Three type aliases are unused and should be deferred.

MarkdownLinterEnabled, MarkdownAssistEnabled, and MarkdownParseInterpolation are defined but not used anywhere in the codebase. Introduce them only when the corresponding configuration fields are actually implemented.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@crates/biome_configuration/src/markdown.rs` around lines 19 - 22, Remove or
defer the unused type aliases MarkdownLinterEnabled, MarkdownAssistEnabled, and
MarkdownParseInterpolation from markdown.rs: they are defined but not
referenced—leave only MarkdownFormatterEnabled for now (or keep as the only
enabled/disabled experimental flag) and add the other aliases back only when you
implement the corresponding config fields or features that reference
MarkdownLinterEnabled, MarkdownAssistEnabled, and MarkdownParseInterpolation
(ensure their definitions are reintroduced alongside the functions/structs that
use them).

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@crates/biome_configuration/src/markdown.rs`:
- Line 50: Replace the colloquial doc comment "What's the max width of a line
applied to Markdown files. Defaults to 80." with a more formal API-style wording
such as "Maximum line width for Markdown files. Defaults to 80." — update the
doc comment attached to the Markdown configuration field (the comment currently
reading "What's the max width of a line applied to Markdown files. Defaults to
80.") so it uses the suggested phrasing for consistency with other biome docs.
- Around line 19-22: Remove or defer the unused type aliases
MarkdownLinterEnabled, MarkdownAssistEnabled, and MarkdownParseInterpolation
from markdown.rs: they are defined but not referenced—leave only
MarkdownFormatterEnabled for now (or keep as the only enabled/disabled
experimental flag) and add the other aliases back only when you implement the
corresponding config fields or features that reference MarkdownLinterEnabled,
MarkdownAssistEnabled, and MarkdownParseInterpolation (ensure their definitions
are reintroduced alongside the functions/structs that use them).

[tidefield]

@ematipico this is ready for review now

[tidefield]

@coderabbitai review

[coderabbitai]

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[coderabbitai]

🧹 Nitpick comments (1)

crates/biome_markdown_formatter/tests/prettier_tests.rs (1)

22-24: with_indent_width(IndentWidth::default()) is redundant.

MarkdownFormatOptions::default() already initialises indent_width to IndentWidth::default(), so the explicit call is a no-op — it just adds noise to the chain.

♻️ Proposed simplification

-    let options = MarkdownFormatOptions::default()
-        .with_indent_style(IndentStyle::Space)
-        .with_indent_width(IndentWidth::default());
+    let options = MarkdownFormatOptions::default()
+        .with_indent_style(IndentStyle::Space);

And you can drop the now-unused IndentWidth import:

-use biome_formatter::{IndentStyle, IndentWidth};
+use biome_formatter::IndentStyle;

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@crates/biome_markdown_formatter/tests/prettier_tests.rs` around lines 22 -
24, Remove the redundant with_indent_width(IndentWidth::default()) call from the
options chain since MarkdownFormatOptions::default() already sets indent_width
to IndentWidth::default(); update the code to just call
MarkdownFormatOptions::default().with_indent_style(IndentStyle::Space) and also
remove the now-unused IndentWidth import to keep imports clean.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Nitpick comments:
In `@crates/biome_markdown_formatter/tests/prettier_tests.rs`:
- Around line 22-24: Remove the redundant
with_indent_width(IndentWidth::default()) call from the options chain since
MarkdownFormatOptions::default() already sets indent_width to
IndentWidth::default(); update the code to just call
MarkdownFormatOptions::default().with_indent_style(IndentStyle::Space) and also
remove the now-unused IndentWidth import to keep imports clean.

[ematipico]

We can't change the configuration. The configuration is public, and it will show up to users the moment we cut a release.

[tidefield]

I removed it.

But what's the concern here? Per #9070 (comment), I assume that users can't use markdown formatter so any markdown configuration is no-op.

[dyc3]

It still makes it public, and it affects our generated schema. People will see it in their autocomplete and get confused on what the status of markdown is, or they will try it an mistakenly assume it works when it doesn't.

[ematipico]

@tidefield

Look at this commit 51fddbe

The hidden files are schema and workspace types. They become public. We expose an option to users (only the schema) that does nothing. Users will start to use suggestions in their IDE (due to autocompletion of the schema).

[tidefield]

Thanks!