# Completed checklists: windows-namespace-request-sys
Append-only. Newest groups at the bottom.
## Moved 2026-09-10 -- NR-1: the per-drive current-directory arm, pinned
### <a id="nr-11"></a>NR-1.1 -- Pin the `=X:` arm of drive-relative rooting. *(completed 2026-09-10 12:24:46 UTC-04:00)*
- [x] **NR-1.1** -- Decide how this crate's tests may control process-global
state, then pin the `=X:` arm of drive-relative rooting.
**Completed in the round that raised it, because the blocker turned out not to
exist.** The item was written to defer the work: pinning the arm needs a
controlled `=X:`, and the two routes to one -- mutating process-global state
that other test threads share, or spawning a child process with a crafted
environment -- looked like a decision about this crate's test shape rather than
something to take in passing.
Measurement dissolved the first route's objection within the hour.
`GetFullPathNameW` **itself** writes the `=X:` entry -- when resolving for a
drive other than the current one, and when the recorded entry is absent or
rejected, in which case it is written as the drive root. (An accepted entry is
left alone, and the current-drive form writes nothing.) The code under test
therefore already mutates that state on the very path these tests exercise, so
a test that sets it first introduces no hazard that resolving alone did not,
and there was nothing left to decide. Isolation across the tests comes from
their disjoint drive letters.
`a_drive_relative_path_uses_that_drives_entry_verbatim_and_rewrites_a_bad_one`
in [drive_entry.rs](src/full_path/tests/drive_entry.rs) now pins all three behaviours: an entry
naming an existing directory is honoured verbatim (onto a *different* drive,
which is what makes "that drive's own current directory" a convention rather
than a guarantee); an entry naming nothing is rejected in favour of the drive
root; and the call writes the entry back, creating it on a host that had none.
It draws its drive letter from a list disjoint from every sibling test's, so
no two can select the same one and race under libtest's thread-per-test model.
*(Later correction, recorded here because the archive is history and the
history was briefly wrong: this entry described the selection as a `W`/`U`
**pair**, matching the helper as written. That helper validated only its first
letter and returned the second unchecked, so the guarantee the pair implied did
not hold. The lists are now three letters each, every candidate is checked
against both the current drive and the probe drive, and the lists themselves
live in one table in [drive_entry.rs](src/full_path/tests/drive_entry.rs) with a test enforcing
that they stay disjoint and long enough. This note deliberately does NOT
enumerate them: an earlier version did, and named five lists after a sixth had
been added -- so a reader picking letters for a seventh would have consulted
an inventory missing three of the letters already in use. The table is the
inventory.)*
The sibling test keeps its weaker form and now says so: without controlling
the entry it can only bound the arm.
*(Later correction: that sibling was named
`a_drive_relative_path_is_rooted_at_that_drive_and_not_the_process_directory`,
and the name claimed two things its assertions do not reach -- `ends_with`
accepts any base, including the process directory, and an accepted entry is
used verbatim so the result need not be on that drive at all. It is now
`a_drive_relative_path_carries_its_component_and_the_current_drive_uses_the_process_directory`.)*