VarDefs.NewAndInit: callInitExpr

[xushiwei]

No description provided.

[gemini-code-assist]

Summary of Changes

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This pull request refactors the variable initialization process within the VarDefs.NewAndInit method. By extracting the logic for handling initialization expressions into a new helper function, callInitExpr, the change aims to enhance code clarity and maintainability for new variable declarations.

Highlights

• Refactoring VarDefs.NewAndInit: The VarDefs.NewAndInit method has been refactored to delegate the handling of initialization expressions to a new helper function, callInitExpr, improving code organization and readability.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.03%. Comparing base (3f6616b) to head (c6835d6).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #562      +/-   ##
==========================================
- Coverage   96.04%   96.03%   -0.01%     
==========================================
  Files          24       24              
  Lines        6718     6717       -1     
==========================================
- Hits         6452     6451       -1     
  Misses        198      198              
  Partials       68       68              

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[gemini-code-assist]

Code Review

This pull request refactors VarDefs.NewAndInit to use the callInitExpr helper function, making it consistent with ClassDefs.NewAndInit. This is a positive change for consistency and adds panic safety to the initialization logic. However, I've identified a potential issue in the callInitExpr function itself that could lead to incorrect behavior in certain edge cases. My review includes a detailed comment on this and a suggestion for how to improve the helper function.

[gemini-code-assist]

While using callInitExpr is good for consistency with ClassDefs.NewAndInit, the current implementation of callInitExpr appears to have a potential bug related to double cleanup.

If fn returns 0 and EndInit(0) doesn't panic (e.g., when NewAndInit is called with no variable names), callInitExpr will execute EndInit(0), and then its deferred function will call ResetInit(). This results in cleanup logic (like commitStmt) being invoked twice, which can lead to incorrect statement ordering.

To fix this, callInitExpr should be refactored to ensure that either EndInit or ResetInit is called, but never both in a non-panicking execution path. Here's a suggested implementation that addresses this while maintaining panic safety:

func callInitExpr(cb *CodeBuilder, fn F) {
	panicking := true
	defer func() {
		if panicking {
			cb.ResetInit()
		}
	}()
	n := fn(cb)
	if n == 0 {
		cb.ResetInit()
	} else {
		cb.EndInit(n)
	}
	panicking = false
}

This revised logic correctly handles all cases, including panics from fn or EndInit, and avoids the double-cleanup problem.