[BUG] Multiplication overflow on max_results * 3 causes panic or wrong results

[Cute0110]

Project

vgrep

Description

The search code multiplies max_results by 3 for reranking purposes, but this multiplication can overflow for large values, causing panic in debug mode or incorrect behavior in release mode.

Error Observation

With large max_results values, the multiplication overflows.

Error Message

thread 'main' panicked at 'attempt to multiply with overflow'

Debug Logs

System Information

Version: 0.1.0

## Operating System
  OS: Ubuntu 24.04.3 LTS
  Kernel: 6.8.0-79-generic
  Arch: x86_64

## Hardware
  CPU: AMD Ryzen 9 5950X 16-Core Processor (4 cores)
  RAM: 11 GB

## Build Environment
  Rust: rustc 1.92.0 (ded5c06cf 2025-12-08)
  Target: x86_64

Screenshots

No response

Steps to Reproduce

1. Open src/core/search.rs line 51:

let candidates = self
    .db
    .search_similar(&query_embedding, &abs_path, max_results * 3)?;  // OVERFLOW!

2. Open src/core/db.rs line 197:

results.truncate(limit * 3); // Get more for reranking - OVERFLOW!

3. Set max_results = 6148914691236517206 (usize::MAX / 3 + 1)
4. Observe overflow panic or wrapping behavior

Expected Behavior

Should use checked_mul or saturating_mul to prevent overflow.

Actual Behavior

Panic in debug mode; silent wraparound producing wrong results in release mode.

Additional Context

No response

[echobt]

Issue validated. The reported problem has been confirmed in the codebase. A Pull Request with the fix has been submitted: CortexLM/vgrep#30.