issue: 4669942 Don't increase error counter on TCP EOF

[pasis]

Description

EOF is a regular scenario. Treating it as an error in the stats can be confusing.

What

Don't treat TCP EOF as an error.

Why ?

Avoid confusion and noise in stats.

Change type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Documentation content changes
• Tests
• Other

Check list

• Code follows the style de facto guidelines of this project
• Comments have been inserted in hard to understand places
• Documentation has been updated (if necessary)
• Test has been added (if possible)

[pasis]

bot:retest

[greptile-apps]

Greptile Overview

Greptile Summary

Fixed TCP EOF handling to prevent it from being counted as an error in socket statistics. EOF is a normal connection termination scenario and should not inflate error counters.

Key Changes:

• Modified handle_rx_error() to only increment error counters when ret == -1
• TCP EOF returns ret = 0, which now correctly bypasses error statistics
• Updated comments in tcp_in.c for improved clarity (no functional changes)

Impact:

• Statistics will now accurately reflect actual errors vs normal connection closures
• Consistent with POSIX behavior where EOF (return 0) is distinct from errors (return -1)

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• The change is minimal, well-targeted, and correct. It adds a simple condition (&& ret == -1) to ensure error counters are only incremented for actual errors, not EOF. The logic properly distinguishes between EOF (ret=0) and errors (ret=-1), which aligns with standard POSIX semantics. The change is consistent with similar patterns in the codebase (e.g., sockinfo.cpp:785).
• No files require special attention

Important Files Changed

File Analysis

Filename	Score	Overview
src/core/sock/sockinfo_tcp.cpp	5/5	Fixed error counter logic to exclude EOF (ret=0) from error statistics

Sequence Diagram

sequenceDiagram
    participant App as Application
    participant SI as sockinfo_tcp
    participant Stats as Socket Stats
    
    App->>SI: recv() call on TCP socket
    SI->>SI: handle_rx_error(blocking)
    
    alt Connection Closed (EOF)
        SI->>SI: ret = 0 (EOF)
        Note over SI: No errno set
    else Other Errors
        SI->>SI: ret = -1
        Note over SI: errno set (EAGAIN, ECONNRESET, etc)
    end
    
    alt ret == -1 (Error)
        SI->>Stats: Increment n_rx_eagain or n_rx_errors
    else ret == 0 (EOF)
        Note over SI,Stats: No error counter incremented
    end
    
    SI->>App: Return ret (0 for EOF, -1 for error)

Loading

_{2 files reviewed, no comments}

_{Edit Code Review Agent Settings | Greptile}

[galnoam]

@pasis , please move to fixed/closed