Comparisons and checks

MFFP0015: Compare FullPath values instead of their string representation

This rule is a warning. It reports a comparison of strings where one of the strings is a FullPath:

• fullPath == text, fullPath != text, fullPath.Value == other.Value, string.Equals(fullPath, text) and fullPath.Value.Equals(text) compare the strings ordinally and case-sensitively, on every operating system. Comparing FullPath values ignores case on Windows, macOS, iOS and tvOS.
• string.Compare(fullPath, text) and fullPath.Value.CompareTo(text) compare the strings with the current culture, so the order of the paths depends on the machine. FullPath values sort ordinally.

To fix it, convert the string to a FullPath and compare the paths: fullPath == FullPath.FromPath(text). Choose the case sensitivity with Equals(other, ignoreCase) or a FullPathComparer: see Comparing paths.

The rule does not report the overloads that take a StringComparison, such as string.Equals(fullPath, text, StringComparison.Ordinal): they state that a string comparison is intended.

MFFP0016: FullPath.Equals with a string argument is always false

This rule is a warning. fullPath.Equals("value"), fullPath.Equals(other.Value) or fullPath.Equals(other.ToString()) calls Equals(object), which returns true for a FullPath only: with a string, the result is always false.

Compare with a FullPath instead: fullPath.Equals(other), or fullPath.Equals(FullPath.FromPath(text)) for a string. The rule does not report an argument typed as object, which can hold a FullPath.

MFFP0018: Path.IsPathRooted and Path.IsPathFullyQualified are redundant on a FullPath

Path.IsPathRooted(fullPath) and Path.IsPathFullyQualified(fullPath) are true for every FullPath except the empty one. The fix replaces them with !fullPath.IsEmpty, which gives the same result.

MFFP0021: Use FullPath.IsEmpty

The rule reports the ways to check for the empty path other than IsEmpty:

The results are the same, and IsEmpty is clearer.