Fix race condition in state.All() method (fixes #309) #329
Conversation
The state.All() method had a race condition where it unlocked the mutex inside the range loop over the map, leaving the map unprotected during iteration. This could trigger the race detector and cause concurrent map access issues. This fix creates a copy of the map while holding the lock, then iterates over the copy without holding the lock. This ensures thread-safe iteration without blocking other operations for extended periods. Fixes google#309
|
Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA). View this failed invocation of the CLA check for more information. For the most up to date status, view the checks section at the bottom of the pull request. |
Summary of ChangesHello @shanto12, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed! This pull request resolves a critical race condition within the Highlights
Using Gemini Code AssistThe full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips. Invoking Gemini You can request assistance from Gemini at any point by creating a comment using either
Customization To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a Limitations & Feedback Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here. You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension. Footnotes
|
![gemini-code-assist[bot]](https://avatars.githubusercontent.com/in/956858?s=60&v=4){kind=small}
There was a problem hiding this comment.
Code Review
This pull request correctly fixes a critical race condition in the state.All() method. The approach of creating a copy of the map under a lock before iterating is sound and effectively prevents concurrent access issues. My review includes a suggestion to further improve the implementation by fixing significant indentation problems, using the more idiomatic maps.Clone function, and renaming a variable that shadows a built-in Go function. Applying this suggestion will enhance the code's readability and maintainability.
| return func(yield func(key string, val any) bool) { | ||
| // Create a copy of the map while holding the lock | ||
| s.mu.RLock() | ||
| copy := make(map[string]any, len(s.state)) | ||
| for k, v := range s.state { | ||
| copy[k] = v | ||
| } | ||
| s.mu.RUnlock() | ||
| if !yield(k, v) { | ||
| return | ||
|
|
||
| // Iterate over the copy without holding the lock | ||
| for k, v := range copy { | ||
| if !yield(k, v) { | ||
| return | ||
| } | ||
| } | ||
| s.mu.RLock() | ||
| } |
There was a problem hiding this comment.
This change correctly fixes the race condition. However, the implementation can be improved:
- Formatting: The indentation throughout this function is incorrect, likely due to a mix of tabs and spaces, which harms readability. Running
gofmtwould resolve this. - Idiomatic Code: The manual map copy can be simplified to a single call to
maps.Clone, which is already used in this package and is more idiomatic. - Naming: The variable name
copyshadows Go's built-incopyfunction. It's a best practice to avoid this by choosing a more descriptive name likestateCopy.
The suggestion below applies all these improvements.
return func(yield func(key string, val any) bool) {
// Create a copy of the map while holding the lock
s.mu.RLock()
stateCopy := maps.Clone(s.state)
s.mu.RUnlock()
// Iterate over the copy without holding the lock
for k, v := range stateCopy {
if !yield(k, v) {
return
}
}
}1 participant
The state.All() method had a race condition where it unlocked the mutex inside the range loop over the map, leaving the map unprotected during iteration. This could trigger the race detector and cause concurrent map access issues.
This fix creates a copy of the map while holding the lock, then iterates over the copy without holding the lock. This ensures thread-safe iteration without blocking other operations for extended periods.
Fixes #309