Formatter: emit canonical blank lines between class sections and methods (BT-985)

[jamesc]

Summary

• Always emit a blank line between class leading comments (e.g. license block) and the doc comment/class header
• Always emit a blank line before the first method in a class body, regardless of whether state declarations exist
• Emit a blank line between consecutive methods within a class

Fixes: https://linear.app/beamtalk/issue/BT-985

Test plan

• beamtalk fmt-check examples/getting-started/src/hello.bt reports no diff
• All idempotency tests pass (hello.bt, hanoi.bt, point.bt)
• just ci passes (2371 Rust tests, 886 stdlib/BUnit, 2208 Erlang tests)

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Improved generated-code formatting: ensures a blank line between leading comments and doc headers.
  • Consistently inserts blank lines between consecutive instance methods, between consecutive class-side methods, and between the last instance method and the first class-side method when both exist.
  • No public or exported signatures were added, removed, or changed.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📥 Commits

Reviewing files that changed from the base of the PR and between f2978c5 and a171910.

📒 Files selected for processing (1)

• crates/beamtalk-core/src/unparse/mod.rs

🚧 Files skipped from review as they are similar to previous changes (1)

• crates/beamtalk-core/src/unparse/mod.rs

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📝 Walkthrough

Walkthrough

Adjusts the unparser's formatting for class-like constructs: inserts a blank line after non-doc leading comments, always adds a blank before the first method when methods exist, separates consecutive instance and class-side methods, and ensures a blank line between instance and class-side method groups.

Changes

Cohort / File(s)	Summary
Unparser formatting crates/beamtalk-core/src/unparse/mod.rs	Inserted blank-line emission after non-doc leading comments; changed method-block blank-line insertion to run unconditionally when any methods exist; switched instance- and class-side method iterations to enumerate and added separators between consecutive methods and between instance vs class-side groups.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• Implement width-aware block formatting in unparser (BT-981) #1025: Modifies the same unparse/mod.rs formatting logic (doc/comment emission and method spacing).
• Implement beamtalk fmt CLI command (BT-978) #1020: Updates unparser formatting and adds idempotency tests that verify unparser spacing/blank-line behavior.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: adding canonical blank lines between class sections and methods in the formatter. It is specific, clear, and directly reflects the changeset.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch worktree-BT-985

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[coderabbitai]

Actionable comments posted: 1

🤖 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/beamtalk-core/src/unparse/mod.rs`:
- Around line 197-201: The loop over class.class_methods currently only inserts
a blank line when i > 0, so the first class-side method isn’t separated from
preceding instance methods; update the condition in the class.class_methods
iteration so a blank line is also emitted when i == 0 and class.instance_methods
is non-empty (i.e., change the if to check `if i > 0 || (i == 0 &&
!class.instance_methods.is_empty())` or equivalent), ensuring you still call
docs.push(line()) in that case (references: class.class_methods,
class.instance_methods, docs.push(line())).

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ℹ️ Review info

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Review profile: CHILL

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Disabled knowledge base sources:

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📥 Commits

Reviewing files that changed from the base of the PR and between 1aa5989 and f2978c5.

📒 Files selected for processing (1)

• crates/beamtalk-core/src/unparse/mod.rs

[Copilot]

Pull request overview

This PR updates the Beamtalk AST unparser/formatter to emit canonical blank-line spacing within class definitions, aligning formatted output with the BT-985 formatting rules.

Changes:

• Emit a blank line between class leading comments and the doc comment/class header.
• Always emit a blank line before the first method in a class when any methods exist (independent of state/classState presence).
• Emit a blank line between consecutive methods (instance-side and class-side) within their respective method lists.