Improved performance and readability of split_idents_on_dot: #6059
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Improved performance and readability of split_idents_on_dot: Reduced unnecessary allocations Simplified control flow Reversed strings in-place using byte manipulation Streamlined complete_opt by flattening iterator chains and minimizing cloning Used sort_unstable() for faster completion list sorting Minor improvements in get_available_completions logic for better clarity and performance
WalkthroughThis update refactors and reorganizes the Changes
Sequence Diagram(s)sequenceDiagram
participant User
participant ShellHelper
participant HelperFunctions
User->>ShellHelper: complete_opt(input)
ShellHelper->>HelperFunctions: split_idents_on_dot(input)
HelperFunctions-->>ShellHelper: idents
ShellHelper->>ShellHelper: get_available_completions(idents)
ShellHelper-->>ShellHelper: Option<(prefix, completions)>
ShellHelper->>ShellHelper: Filter & sort completions
ShellHelper-->>User: Vec<String> (completions)
Estimated code review effort🎯 2 (Simple) | ⏱️ ~8 minutes Poem
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Actionable comments posted: 1
📜 Review details
Configuration used: .coderabbit.yml
Review profile: CHILL
Plan: Pro
📒 Files selected for processing (1)
src/shell/helper.rs(4 hunks)
🧰 Additional context used
📓 Path-based instructions (1)
**/*.rs
📄 CodeRabbit Inference Engine (.github/copilot-instructions.md)
**/*.rs: Follow the default rustfmt code style (cargo fmtto format)
Always run clippy to lint code (cargo clippy) before completing tasks. Fix any warnings or lints that are introduced by your changes
Follow Rust best practices for error handling and memory management
Use the macro system (pyclass,pymodule,pyfunction, etc.) when implementing Python functionality in Rust
Files:
src/shell/helper.rs
🧠 Learnings (1)
📚 Learning: applies to **/*.rs : use the macro system (`pyclass`, `pymodule`, `pyfunction`, etc.) when implement...
Learnt from: CR
PR: RustPython/RustPython#0
File: .github/copilot-instructions.md:0-0
Timestamp: 2025-07-19T03:16:56.511Z
Learning: Applies to **/*.rs : Use the macro system (`pyclass`, `pymodule`, `pyfunction`, etc.) when implementing Python functionality in Rust
Applied to files:
src/shell/helper.rs
🔇 Additional comments (5)
src/shell/helper.rs (5)
16-18: LGTM: Idiomatic constructor patternUsing
Self { vm, globals }instead of the explicit struct name is more idiomatic and maintainable in Rust.
20-43: Excellent safety and readability improvementsThe refactoring improves the code in multiple ways:
- Using
split_first()?instead ofunwrap()prevents potential panics- The simplified attribute lookup chain is more readable
- Returning a single chained iterator is more efficient than handling separate iterators
- The renamed closure
get_str_iteris more descriptive
45-77: Good performance optimizations and code clarityThe restructuring provides several benefits:
- More logical flow by calling
split_idents_on_dotfirst- Early error filtering with
filter_map(Result::ok)is efficient- The explicit underscore filtering logic is clearer than the previous implementation
- Using
sort_unstable()is a good performance optimization for this use case- Collecting owned strings is appropriate for the return type
79-116: Improved safety and control flowThe rewrite using
while letprovides better control over iteration and improves safety:
- Using
map_or(false, |s| s.is_empty())prevents potential panics- The explicit iterator handling makes the logic clearer
- The startpos calculation and character handling logic is preserved correctly
- The function maintains the same behavior while being more robust
141-141: Minor style improvementUsing
&line[..pos]instead of&line[0..pos]is more idiomatic in Rust.
| fn reverse_string(s: &mut String) { | ||
| unsafe { | ||
| let bytes = s.as_bytes_mut(); | ||
| bytes.reverse(); | ||
| } | ||
| } |
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Critical: Unsafe string reversal breaks UTF-8 invariants
This unsafe optimization is incorrect and dangerous. Reversing UTF-8 bytes directly will corrupt multi-byte Unicode characters, violating Rust's UTF-8 string invariants and potentially causing undefined behavior.
For example, the string "café" (with é as U+00E9, encoded as bytes [0xC3, 0xA9]) would become invalid UTF-8 after byte reversal.
Revert to the safe character-based approach:
-fn reverse_string(s: &mut String) {
- unsafe {
- let bytes = s.as_bytes_mut();
- bytes.reverse();
- }
-}
+fn reverse_string(s: &mut String) {
+ let reversed: String = s.chars().rev().collect();
+ *s = reversed;
+}If performance is critical, consider using a safer approach like s.as_mut_str().chars().rev().collect() or validate that all input is ASCII-only.
📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| fn reverse_string(s: &mut String) { | |
| unsafe { | |
| let bytes = s.as_bytes_mut(); | |
| bytes.reverse(); | |
| } | |
| } | |
| fn reverse_string(s: &mut String) { | |
| let reversed: String = s.chars().rev().collect(); | |
| *s = reversed; | |
| } |
🤖 Prompt for AI Agents
In src/shell/helper.rs around lines 118 to 123, the current unsafe method
reverses the string by directly reversing its bytes, which breaks UTF-8 encoding
and can cause undefined behavior. Replace this unsafe byte reversal with a safe
character-based reversal by converting the string to characters, reversing them,
and collecting back into the string. This ensures UTF-8 validity is maintained.
If performance is a concern, ensure input is ASCII-only before using byte
reversal or stick to the safe char-based method.
Improved performance and readability of split_idents_on_dot:
Reduced unnecessary allocations
Simplified control flow
Reversed strings in-place using byte manipulation
Streamlined complete_opt by flattening iterator chains and minimizing cloning
Used sort_unstable() for faster completion list sorting
Minor improvements in get_available_completions logic for better clarity and performance
Summary by CodeRabbit
Refactor
Style