refactor(repl): optimize shell_exec and REPL loop for clarity and eff… #6058

haffizaliraza · 2025-08-01T14:42:35Z

…iciency

refactor(repl): optimize shell_exec and REPL loop for clarity and efficiency

Consolidated error matching in shell_exec to reduce branching and improve maintainability
Reorganized REPL loop to simplify control flow and minimize repeated logic
Improved string handling to reduce unnecessary

Summary by CodeRabbit

Refactor
- Improved error handling and control flow in the interactive shell for clearer prompts and more accurate feedback on input errors.
- Streamlined history file management and prompt display for a smoother user experience.
- Enhanced handling of keyboard interrupts and end-of-file situations, resulting in more intuitive shell behavior.

…iciency refactor(repl): optimize shell_exec and REPL loop for clarity and efficiency - Consolidated error matching in `shell_exec` to reduce branching and improve maintainability - Reorganized REPL loop to simplify control flow and minimize repeated logic - Improved string handling to reduce unnecessary

coderabbitai · 2025-08-01T14:42:43Z

Walkthrough

The changes refactor and simplify error handling and control flow in the REPL logic within src/shell.rs. Pattern matching for parsing and lexical errors is consolidated, redundant variables and nested conditions are removed, and prompt and history path retrievals are streamlined. No public API signatures are altered.

Changes

Cohort / File(s)	Change Summary
Shell Error Handling & REPL Refactor `src/shell.rs`	Refactored error handling in `shell_exec` to consolidate and clarify pattern matching for parse and lexical errors. Simplified prompt, history file path, and REPL loop control flow. Improved state management and exception printing. No changes to public function signatures.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~15 minutes

Poem

In the shell, where errors once nested deep,
The code now flows with clarity to keep.
Prompts and paths, now easy to find,
Less tangled state, more peace of mind.
A rabbit hops through REPL’s new delight—
Simpler, cleaner, shining bright!
🐇✨

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Review profile: CHILL
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📥 Commits

Reviewing files that changed from the base of the PR and between 4841776 and e67bf9f.

📒 Files selected for processing (1)

src/shell.rs (2 hunks)

🧰 Additional context used

📓 Path-based instructions (1)

**/*.rs

📄 CodeRabbit Inference Engine (.github/copilot-instructions.md)

**/*.rs: Follow the default rustfmt code style (cargo fmt to 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.rs

🧠 Learnings (3)

📓 Common learnings

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 : Follow Rust best practices for error handling and memory management

📚 Learning: applies to **/*.rs : follow rust best practices for error handling and memory management...

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 : Follow Rust best practices for error handling and memory management

Applied to files:

src/shell.rs

📚 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.rs

🔇 Additional comments (9)

src/shell.rs (9)

3-9: Import reorganization looks good.

The explicit imports for error types support the cleaner pattern matching in the refactored code.

28-37: Excellent use of functional error handling.

The refactored Ok branch using map and unwrap_or_else is more idiomatic and concise than the previous if-else structure.

39-89: Well-structured error pattern matching.

The consolidated error handling with direct pattern matching on ParseErrorType and LexicalErrorType significantly improves readability and maintainability. The removal of the bad_error boolean in favor of direct result returns makes the control flow much clearer.

50-56: Potential edge case in triple-quote detection.

The logic for detecting triple-quoted strings skips to the error location and checks for three consecutive quotes. However, this might not correctly handle all edge cases, such as when the quotes are escaped or when there are spaces between quotes.

Consider verifying this logic handles various quote scenarios correctly:
#!/usr/bin/env python3
# Test various unclosed string scenarios
test_cases = [
    '"""unclosed triple',
    "'''unclosed triple",
    '"unclosed single',
    '"\\"unclosed with escape',
    '" " "spaced quotes',
]

for test in test_cases:
    print(f"Testing: {test!r}")
    try:
        compile(test, '<stdin>', 'exec')
    except SyntaxError as e:
        print(f"  Error: {e}")
101-103: Clean functional approach for history path construction.

The chained map and unwrap_or_else pattern is more idiomatic than the previous match statement.

113-115: Concise prompt retrieval logic.

The single expression using and_then, map, and unwrap_or effectively handles all the edge cases while being more readable.

133-147: Simplified control flow in the main REPL loop.

The refactored match arms with direct state transitions and inline error printing make the REPL logic much easier to follow. The removal of redundant clearing of continuing_block when it's already false (line 135-138) is a good optimization.

149-163: Improved interrupt and error handling.

Printing exceptions directly instead of propagating them as errors is appropriate for a REPL context. The merged EOF and error cases (lines 157-163) reduce code duplication.

1-170: Manual style and lint verification required

The sandbox environment couldn’t run rustfmt or clippy due to missing /proc. Please verify locally that the changes conform to our style guidelines and introduce no new warnings:

Run cargo fmt -- --check src/shell.rs and fix any formatting issues.

Run cargo clippy --all-targets -- -D warnings and address all lints.

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youknowone

Please describe your purpose in details.

What exactly did you optimize?
Why each comment is removed?
Why did you change each part?

Did you test the build after patch?

youknowone · 2025-08-04T07:58:26Z

src/shell.rs

-        None => ".repl_history.txt".into(),
-    };
+    let repl_history_path = dirs::config_dir()
+        .map(|mut path| { path.push("rustpython/repl_history.txt"); path })


Is this also windows(backslash) compatible?

youknowone · 2025-08-04T07:59:04Z

src/shell.rs

@@ -26,211 +22,148 @@ fn shell_exec(
    empty_line_given: bool,
    continuing_block: bool,
 ) -> ShellExecResult {
-    // compiling expects only UNIX style line endings, and will replace windows line endings


is this comment outdated?

youknowone requested changes Aug 4, 2025

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