Documentation for FileInfo.Exists and File.Exists is misleading about dotnet-api-docs HOT 5 OPEN

Please note the XML comments as viewed by Visual Studio also need to be updated.

from dotnet-api-docs.

The key thing is that the API returns false if the file doesn't exist or if it is unable to determine the file's status (which can be a number of reasons).

A common mistake should be called out, and that is making assumptions based on the results of this or any other I/O API is dangerous. I/O is transient, and as such you always need to catch errors when attempting to access or modify files (reading/writing/copying/etc.). For example: If File.Exists() returns true it was true at one point during the call to File.Exists(). It may no longer be true even by the time the API returns. Some other process may have moved or deleted the file, remote or removable media may become disconnected or unreachable. Even if the risk of the file being deleted/disconnected is low, permissions can fail for a variety of reasons, including interaction with things such as antivirus programs and indexers.

from dotnet-api-docs.

Thanks @jhudsoncedaron and @JeremyKuhne. The way I see this, we need to update the API docs to change the description/remarks and some of the IO conceptual articles to explain the transient nature of I/O operations. The IntelliSense gets updated with the content fixes we make here on a certain cadence.

from dotnet-api-docs.

@mairaw The way I ended up caring about this was a transient network failure causing a spurious false from File.Exists() causing huge problems in production and to me that's what needs documenting the most.

from dotnet-api-docs.

Thanks for the example @jhudsoncedaron. That helps.

from dotnet-api-docs.