Once upon a time I worked at a company on an automated testing system. It had lots of "interesting" things in their code-base, but one that stood out was one of the error messages:

Error 718: Missing files cannot be found

Of course. If the file is missing, it cannot be found. What's the story?

List of missing files

The system had a step checking if all the required files are present and it created a list of the files that were missing and saved it in a file called missing_files.txt.

A later step then would read the content of missing_files.txt and report it it.

The question was, what to do if the file "missing_files.txt" did not exist? The rather unfortunate choice was to report Missing files cannot be found with an obscure error number.

The problem was made worse as the 'missing_files.txt' file would only be created if there was at least one missing file. In normal circumstances, when all the files were supplied, the 'missing_files.txt' was not created and this the error was reported.

Yes I know. This whole thing looks strange.

Better solution?

A much better choice would have been an error message such as The 'missing_files.txt' file could not be found. with possibly a link to a much more detailed explanation.

An even better solution would be probably to alway create the 'missing_files.txt' file, but leave it empty if there are no missing file.