Checking for file existence or access), however it is done, often leads to subtle race conditions. Subtle is a word strongly suggesting unchecked assumptions. B

Checking for file existence or access), however it is done, often leads to subtle race conditions. Subtle is a word strongly suggesting unchecked assumptions. Bugs come from unchecked assumptions. Generally, just act on the file system. Expect errors to happen and handle them. Even if it's potentially slower. Unless, and in fact I'll say only if, your company is a hot startup revolutionizing file system semantics. More generally, do not be clever about solving problems outside your bailiwick. Unless you want to blog about it and misattribute blame to something like fixing unit tests. (Aside: sounds like the unit tests also had unchecked assumptions.)