Summary

file_already_mined() in palace.py:68 uses strict float equality to compare stored vs current mtime:

return float(stored_mtime) == current_mtime

os.path.getmtime() returns a float. ChromaDB stores metadata via JSON serialization, which introduces floating-point precision loss (e.g., 1712345678.123456 may round-trip as 1712345678.1234560012817383). The strict == comparison frequently fails even for unchanged files, causing every file to be re-mined on every run.

This defeats the entire dedup/skip mechanism and silently bloats the palace with duplicate drawers.

Reproduction

1. mempalace init <dir> && mempalace mine <dir> — initial mine
2. mempalace mine <dir> — re-mine without changing any files
3. Observe that all files are processed again (not skipped)

Suggested Fix

Use epsilon comparison:

return abs(float(stored_mtime) - current_mtime) < 0.01

Or truncate to integer seconds:

return int(float(stored_mtime)) == int(current_mtime)

Environment

• mempalace 3.1.0
• ChromaDB 0.6.3
• Linux x86_64, Python 3.12