fix: pdcp data loss, pipeline conn leak, Close() race, FilterCustom error swallowing

[tal7aouy]

Summary

Fixes four bugs found during a code audit of the codebase.

---

Bugs Fixed

1. PDCP Writer: Data Loss When Chunk Exceeds MaxChunkSize

File: internal/pdcp/writer.go

When a result line would push the buffer over MaxChunkSize (4 MB), the buffer was flushed, but the current line was never written to the newly emptied buffer. This silently dropped every result that triggered a flush.

Before

if buff.Len()+len(line) > MaxChunkSize {
    if err := u.uploadChunk(buff); err != nil {
        gologger.Error().Msgf("Failed to upload asset results on cloud: %v", err)
    }
} else {
    buff.WriteString(line)
    buff.WriteString("\n")
}

After

if buff.Len()+len(line) > MaxChunkSize {
    if err := u.uploadChunk(buff); err != nil {
        gologger.Error().Msgf("Failed to upload asset results on cloud: %v", err)
    }

    // Write the current line to the now-empty buffer so it is not lost.
    buff.WriteString(line)
    buff.WriteString("\n")
} else {
    buff.WriteString(line)
    buff.WriteString("\n")
}

---

2. Pipeline: Connection Leak in SupportPipeline

File: common/httpx/pipeline.go

The dialed TCP/TLS connection was never closed on either the success or error path, leaking one file descriptor per call.

A defer conn.Close() was added immediately after a successful connection.

conn, err := pipelineDial(protocol, addr)
if err != nil {
    return false
}

defer conn.Close()

---

3. PDCP Writer: Race Condition in Close()

File: internal/pdcp/writer.go

The Load() → close() → Store() sequence around close(u.data) was not atomic. Concurrent calls to Close() could both pass the check, causing the second close(u.data) to panic with:

close of closed channel

Replaced the sequence with an atomic CompareAndSwap.

Before

func (u *UploadWriter) Close() {
    if !u.closed.Load() {
        close(u.data)
        u.closed.Store(true)
    }
    <-u.done
}

After

func (u *UploadWriter) Close() {
    if !u.closed.CompareAndSwap(false, true) {
        return
    }

    close(u.data)
    <-u.done
}

---

4. FilterCustom: Errors from Callbacks Silently Swallowed

File: common/httpx/filter.go

If a callback returned either (true, error) or (false, error), the error was silently discarded and iteration continued. As a result, the function could incorrectly return (false, nil) even though a callback had returned an error.

Errors are now propagated immediately.

Before

for _, callback := range f.CallBacks {
    ok, err := callback(response)
    if ok && err == nil {
        return true, err
    }
}

return false, nil

After

for _, callback := range f.CallBacks {
    ok, err := callback(response)
    if err != nil {
        return false, err
    }

    if ok {
        return true, nil
    }
}

return false, nil

---

Test Plan

• go test ./common/httpx/ -run TestFilterCustom -v
  • New test covers all four callback scenarios:
    • Error with ok=true
    • Error with ok=false
    • First callback matches
    • No callbacks match
• go vet ./common/httpx/ ./internal/pdcp/
• go build ./common/httpx/ ./internal/pdcp/
• go test ./common/httpx/ -short -count=1
  • Full package test suite passes.

Summary by CodeRabbit

• Bug Fixes

  • Improved callback error handling so errors are reported immediately.
  • Prevented data loss when processing full-size chunks.
  • Ensured data channels are closed safely and only once.
  • Improved connection cleanup after successful pipeline setup.

• Tests

  • Added coverage for callback errors, successful matches, and unmatched filters.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 9f0f57ce-1296-4868-872f-515fd3b7d545

📥 Commits

Reviewing files that changed from the base of the PR and between 8114098 and ca92e9f.

📒 Files selected for processing (4)

• common/httpx/filter.go
• common/httpx/filter_test.go
• common/httpx/pipeline.go
• internal/pdcp/writer.go

---

Walkthrough

The change fixes callback error propagation, pipeline connection cleanup, and PDCP writer behavior. It also prevents oversized result loss and makes writer channel closure safe for repeated calls.

Changes

Filter callback handling

Layer / File(s)	Summary
Filter result handling common/httpx/filter.go, common/httpx/filter_test.go	FilterCustom.Filter returns callback errors immediately. Tests cover errors, successful matches, and no matches.

Pipeline connection cleanup

Layer / File(s)	Summary
Pipeline connection lifecycle common/httpx/pipeline.go	SupportPipeline defers connection closure after a successful pipelineDial call.

PDCP writer correctness

Layer / File(s)	Summary
Buffer retention and safe closure internal/pdcp/writer.go	The writer preserves the current result after flushing a full buffer. Close uses atomic compare-and-swap before closing the data channel.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Poem

A rabbit checks the filter’s trail,
And keeps each error in the tale.
The pipeline shuts its door with care,
While buffered lines remain in there.
One close claim guards the channel tight.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes all four bug fixes addressed by the pull request.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

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