Summary

The gcinfo() function in luau returns only the integer part of memory usage in KB, stripping the fractional bytes portion that is present in standard lua implementations.

Steps to Reproduce

echo "print(gcinfo())" > test.luau && luau test.luau    # Output: 36

Expected Behavior

Based on standard lua behavior of collectgarbage('count'), gcinfo() should return the memory usage in KB as a floating-point number, including fractional bytes. This value multiplied by 1024 gives the exact number of bytes in use.
For comparison:

• Lua 5.1: 26.814453125
• Lua 5.2: 21.8193359375
• Lua 5.3: 22.8564453125
• Lua 5.4: 20.8408203125

Actual Behavior

Luau returns only the integer part: 36

Test Commands Used

# Standard Lua versions for comparison
lua51 -e "print(collectgarbage('count'))"    # Output: 26.814453125
lua52 -e "print(collectgarbage('count'))"    # Output: 21.8193359375
lua53 -e "print(collectgarbage('count'))"    # Output: 22.8564453125
lua54 -e "print(collectgarbage('count'))"    # Output: 20.8408203125

# Luau behavior
echo "print(gcinfo())" > test.luau && luau test.luau    # Output: 36

Impact

This bug affects:

• Code portability between Lua and Luau
• Memory profiling accuracy
• Applications that rely on precise memory usage measurements

Additional Context

The gcinfo() function is documented as returning "the total heap size in kilobytes", without mentioning that it should be truncated to an integer.