address comments

Author: timotheecour

changelog.md

@@ -25,7 +25,9 @@
   It didn't work well together with the existing inplace version of the same proc
   (`tables.merge(var CountTable, CountTable)`).
   It was an oversight to be included in v1.0.
-
+- `relativePath("foo", "foo")` is now `"."`, not `""`, as `""` means invalid path
+  and shouldn't be conflated with `"."`; use -d:nimOldRelativePathBehavior to restore the old
+  behavioe
 
 ### Breaking changes in the compiler
 

lib/pure/os.nim

@@ -417,7 +417,8 @@ proc relativePath*(path, base: string; sep = DirSep): string {.
     if not f.hasNext(path): break
     ff = f.next(path)
 
-  if result.len == 0: result.add "."
+  when not defined(nimOldRelativePathBehavior):
+    if result.len == 0: result.add "."
 
 proc isRelativeTo*(path: string, base: string): bool {.since: (1, 1).} =
   ## Returns true if `path` is relative to `base`.