Deduplicators are case-sensitive on Windows

[dwickern]

File paths with different case are logically equal on Windows: new File("foo") == new File("FOO").

Deduplicators use basic string equality to compare file paths (SbtWeb.scala#L419). If two file paths use different case, they will not be passed together through the deduplicator. This eventually results in a Duplicate mappings error.

[jroper]

How does this practically manifest itself? Generally mappings are generated by inspecting the file system, so two mappings with the same path should have the same case. If a mapping was manually configured, and the case didn't match what was on the filesystem, then you'd have a problem where the build would only work on case insensitive file systems - fixing that in sbt-web only solves the problem until someone goes and runs the build on Linux and it doesn't work.