internal/buffer: set closed flag when closing channel in the Load method

[tsukiyoz]

Description

This PR fixes a bug in the Unbounded.Load() method where the closed flag was not being set to true when the channel was closed.

Problem

In the Load() method, when the condition b.closing && !b.closed is met, the code closes the channel but doesn't update the closed flag. This creates an inconsistent state where:

• The channel is closed (no more data can be sent)
• But b.closed remains false

This inconsistency could potentially cause issues in code that relies on the closed flag to determine the buffer's state.

Solution

Added b.closed = true before close(b.c) in the else if branch of the Load() method to ensure the closed flag accurately reflects the buffer's state.

Changes

• File: internal/buffer/unbounded.go
• Method: Load()
• Line: 86
• Change: Added b.closed = true before closing the channel

Testing

• ✅ All existing tests pass
• ✅ No linter errors introduced
• ✅ The fix ensures consistent state between channel closure and closed flag

Impact

This is a bug fix that improves the correctness of the Unbounded buffer implementation without changing its public API or behavior from a user perspective.

Fixes: #8572

RELEASE NOTES: None

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: tsukiyoz / name: tsukiyo (2b9161d)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.84%. Comparing base (8420f3f) to head (2b9161d).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #8575      +/-   ##
==========================================
- Coverage   80.91%   80.84%   -0.07%     
==========================================
  Files         413      413              
  Lines       40751    40754       +3     
==========================================
- Hits        32972    32947      -25     
- Misses       6155     6178      +23     
- Partials     1624     1629       +5     

Files with missing lines	Coverage Δ
internal/buffer/unbounded.go	86.04% <100.00%> (-13.96%)	⬇️

... and 19 files with indirect coverage changes

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[tsukiyoz]

how to add labels to PR 🥲

[eshitachandwani]

Hey, I have added the labels. I think it is permission setting restricting you to add labels.

[eshitachandwani]

Adding @arjan-bal as a reviewer.

[arjan-bal]

LGTM, thanks for the fix.

[arjan-bal]

This bug could have caused a panic if Load() was called after the channel is already closed once. I audited all the usages of Load() and verified that they either use the val, ok := <- ch.Load() syntax or a range based for loop to avoid calling Load() on a closed channel.