drive: fix StatCache mishandling of paths with spaces

Fix "file not found" errors when WebDAV clients access files/dirs inside
directories with spaces.

The issue occurred because StatCache was mixing URL-escaped and
unescaped paths, causing cache key mismatches.
Specifically, StatCache.set() parsed WebDAV responses containing
URL-escaped paths (ex. "Dir%20Space/file1.txt") and stored them
alongside unescaped cache keys (ex. "Dir Space/file1.txt").
This mismatch prevented StatCache.get() from correctly determining whether
a child file existed.

See https://github.com/tailscale/tailscale/issues/13632#issuecomment-3243522449
for the full explanation of the issue.

The decision to keep all paths references unescaped inside the StatCache
is consistent with net/http.Request.URL.Path and rewrite.go (sole consumer)

Update unit test to detect this directory space mishandling.

Fixes tailscale#13632

Signed-off-by: Craig Hesling <craig@hesling.com>

0 files changed, 0 insertions, 0 deletions