os: drop unnecessary trailing . from symlink targets
Adjust splitPathInRoot to match its documented behavior
of dropping . path components except at the end of the path.
This function takes a prefix, path, and suffix; previously
it would preserve a trailing . at the end of the path
even when joining to a suffix.
The practical effect of this change is that we we'll skip
a pointless open of . when following a symlink under some
circumstances:
- open "a/target"
- "a" is a symlink to "b/."
- previously: we rewrite our path to "b/./target"
- now: we rewrite our path to "b/target"
This is a fairly unimportant edge case, and our observable
behavior isn't changing. The main motivation for this change is
that the overall behavior is more comprehensible if splitPathInRoot
follows its documentation.
Change-Id: I96c6a5e3f489cdac991ba1bd702180d69625bc64
Reviewed-on: https://go-review.googlesource.com/c/go/+/630615 Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>