refactor: remove defer in loop
#20223
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WalkthroughWalkthroughThe recent changes across the codebase focus on refining error handling and resource management practices. By utilizing closures and optimizing resource closure strategies, these updates enhance error reporting, streamline resource cleanup, and improve the overall code reliability. These adjustments aim to enhance control flow, aligning with best practices in software development. Changes
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x/group/keeper/invariants.go
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| err = memIt.Close() | ||
| if err != nil { | ||
| return "", broken | ||
| } |
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Ensure proper error handling when closing the memIt iterator.
- err = memIt.Close()
- if err != nil {
- return "", broken
- }
+ if err := memIt.Close(); err != nil {
+ return fmt.Sprintf("failed to close member iterator: %v", err), true
+ }This change ensures that any error during the closing of the memIt iterator is properly handled and reported, which aligns with the PR's objective of improving error handling in resource management.
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Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation.
| err = memIt.Close() | |
| if err != nil { | |
| return "", broken | |
| } | |
| if err := memIt.Close(); err != nil { | |
| return fmt.Sprintf("failed to close member iterator: %v", err), true | |
| } |
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Thanks for your review! @tac0turtle I'll update the PR title from Please let me know if you have any other suggestions or concerns. I appreciate your feedback and support! |
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Thank you for these fixes @tropicaldog! I've added some suggestions for correctness by using anonymous closures because the current changes make the resource releases less likely due to the large number of branches.
Also you could please update the commit description to say
In Go, defers are only invoked in a terminal statement such as a return or panic;
invoking them in a for-loop means that all those resources will not be released
and will build up until the entire function returns or panics
store/migration/manager.go
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| defer batch.Close() | ||
|
|
||
| if err := batch.Set(csKey, csBytes); err != nil { | ||
| return fmt.Errorf("failed to write changeset to db.Batch: %w", err) | ||
| } | ||
| if err := batch.Write(); err != nil { | ||
| return fmt.Errorf("failed to write changeset to db: %w", err) | ||
| } | ||
| if err := batch.Close(); err != nil { | ||
| return fmt.Errorf("failed to close batch: %w", err) | ||
| } |
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The problem with the current change is that if batch.Set or batch.Write fail, then batch.Close() will now not be invoked. I do understand the importance of removing defers in the loop to avoid lingering resources that won't be cleaned up until a panic or a return, but the better fix for this would be making an anonymous closure so
// Invoking this code in a closure so that defer is called immediately on return
// yet not in the for-loop which can leave resource lingering.
err := func() error {
defer batch.Close()
if err := batch.Set(csKey, csBytes); err != nil {
return fmt.Errorf("failed to write changeset to db.Batch: %w", err)
}
if err := batch.Write(); err != nil {
return fmt.Errorf("failed to write changeset to db: %w", err)
}
}()
if err != nil {
return err
}| @@ -76,7 +76,6 @@ func GroupTotalWeightInvariantHelper(ctx sdk.Context, storeService storetypes.KV | |||
| msg += fmt.Sprintf("error while returning group member iterator for group with ID %d\n%v\n", groupInfo.Id, err) | |||
| return msg, broken | |||
| } | |||
| defer memIt.Close() | |||
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Your change to move it down below creates an even less likely chance that memIt.Close() due to the large number of branches that could return before it is invoked. You could apply that anonymous closure trick that I showed up above.
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Much appreciated @odeke-em for your insightful review. I have refactored the code, could you kindly take a look. Thank you!
tropicaldog
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Almost there, thank you @tropicaldog! Just ensure that you whenever you make a closure; that you hoist all the code within the control flow so as to keep it logically the same.
| var groupMember group.GroupMember | ||
| _, err = memIt.LoadNext(&groupMember) | ||
| if errors.ErrORMIteratorDone.Is(err) { | ||
| break |
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personal preference: break is good and does the job but you can also do return nil here already to exit early. There is nothing going on after the loop and a return would make it slightly more readable.
|
@tropicaldog could you rebase, we added store/v1 back to main so the files changed |
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Review Details
Configuration used: .coderabbit.yml
Review profile: CHILL
Files selected for processing (2)
- store/snapshots/store.go (2 hunks)
- store/v2/commitment/store.go (1 hunks)
Additional Context Used
Path-based Instructions (2)
store/snapshots/store.go (1)
Pattern
**/*.go: Review the Golang code for conformity with the Uber Golang style guide, highlighting any deviations.store/v2/commitment/store.go (1)
Pattern
**/*.go: Review the Golang code for conformity with the Uber Golang style guide, highlighting any deviations.
Additional comments not posted (3)
store/snapshots/store.go (2)
143-143: Ensure proper error handling and resource management in the goroutine.
154-163: Refactoring to removedeferinside the loop is correctly implemented.Verification successful
Refactoring to remove
deferinside the loop in theLoadfunction appears to be correctly integrated and functioning as expected based on the test cases provided instore/snapshots/store_test.go. The error handling is consistently checked, ensuring that no errors occur during the operations, which aligns with the intended behavior post-refactoring.
store/snapshots/store_test.go: Various test cases check for errors after callingLoad, confirming that the function handles errors as expected.Scripts Executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Verify the integration of the `Load` function with other parts of the system. # Test: Search for usages of the `Load` function. Expect: Correct handling of the returned error and channel. rg --type go $'Load\('Length of output: 3061
Script:
#!/bin/bash # Description: Verify the error handling and resource management in the refactored `Load` function. # Test: Search for error handling patterns in the files where `Load` is used, focusing on the `store/snapshots/store.go` and related test files. rg --type go -C 5 'if err := store.Load' store/snapshots/store.go store/snapshots/store_test.goLength of output: 97
Script:
#!/bin/bash # Description: Broaden the search for error handling and resource management patterns around the `Load` function. # Test: Search for general patterns of error handling and resource management in the files where `Load` is used, focusing on the `store/snapshots/store.go` and related test files. rg --type go -C 5 'err.*store.Load' store/snapshots/store.go store/snapshots/store_test.goLength of output: 3089
store/v2/commitment/store.go (1)
402-404: Ensure proper resource management by directly handling theCloseoperation.Verification successful
The review of the direct handling of the
Close()operation in thestore/v2/commitment/store.gofile has been verified against the broader codebase. The findings confirm that both direct and deferredClose()operations are used throughout the codebase, depending on the context and specific requirements for resource management. The direct handling in the provided snippet is consistent with a deliberate approach to ensure timely resource release, which is crucial in scenarios where resource locks or file handles need to be explicitly controlled.
- The direct
Close()instore/v2/commitment/store.gois appropriate for the context and aligns with practices observed in other critical parts of the codebase.Scripts Executed
The following scripts were executed for the analysis:
Script:
#!/bin/bash # Description: Verify proper resource management by directly handling the `Close` operation. # Test: Search for direct `Close` calls in the codebase. Expect: Proper resource management. rg --type go $'Close\('Length of output: 41062
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Files selected for processing (1)
- store/snapshots/store.go (3 hunks)
Files skipped from review as they are similar to previous changes (1)
- store/snapshots/store.go
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Files selected for processing (1)
- x/group/keeper/msg_server.go (1 hunks)
Additional Context Used
Path-based Instructions (1)
x/group/keeper/msg_server.go (1)
Pattern
**/*.go: Review the Golang code for conformity with the Uber Golang style guide, highlighting any deviations.
x/group/keeper/msg_server.go
Outdated
| err = k.GasService.GasMeter(ctx).Consume(gasCostPerIteration, "vote on proposal") | ||
| if err != nil { | ||
| return &group.MsgSubmitProposalResponse{ProposalId: id}, errorsmod.Wrap(err, "the proposal was created but failed on gas consumption for vote") | ||
| } |
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Consider optimizing gas consumption handling.
The current implementation consumes gas for each vote within the loop. This could lead to high gas costs if there are many proposers. Consider batching these operations or implementing a more efficient gas management strategy to optimize resource usage.
Head branch was pushed to by a user without write access
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Review Details
Configuration used: .coderabbit.yml
Review profile: CHILL
Files selected for processing (2)
- store/v2/commitment/store.go (1 hunks)
- store/v2/migration/manager.go (1 hunks)
Additional Context Used
Path-based Instructions (2)
store/v2/migration/manager.go (1)
Pattern
**/*.go: Review the Golang code for conformity with the Uber Golang style guide, highlighting any deviations.store/v2/commitment/store.go (1)
Pattern
**/*.go: Review the Golang code for conformity with the Uber Golang style guide, highlighting any deviations.
Additional comments not posted (2)
store/v2/migration/manager.go (1)
184-198: RefactoredwriteChangesetto use a closure fordeferensures immediate resource release, aligning with best practices.store/v2/commitment/store.go (1)
414-416: Properly handling the error onimporter.Close()enhances robustness in resource management.
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@tac0turtle Hi could you re-review, I've fixed the conflicts with main. |
Description
Remove all occurrences of
deferin loophttps://stackoverflow.com/questions/45617758/proper-way-to-release-resources-with-defer-in-a-loop
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Summary by CodeRabbit
Loadmethod of theStorestruct.SubmitProposalfunction of theKeeperstruct inmsg_server.go.importer.Close()method call instore/v2/commitment/store.go.writeChangesetmethod instore/v2/migration/manager.goto ensure immediate defer execution on return for proper resource handling.