Adds cbm_workspace_classify_root, the breadth half of the workspace
boundary. It answers "is this path obviously too broad or too sensitive to
index as one root", not "is this caller allowed to index it" — that second
question needs the user-level grant store, since it is the only input a
caller cannot write. The header says so, because a reader who mistakes one
for the other would draw the wrong conclusion about what is enforced.
Three rules, each doing what the others cannot:
- Depth below the volume. Two components on POSIX refuses every top-level
tree in one rule with no list to maintain. Windows and UNC count
drive/share-relative and require one, because there the first component is
already user space ("D:/repos") — the system trees that sit at the same
depth ("C:/Windows") are covered by name instead, which is tractable
because that set is small and stable.
- The home directory itself, which is two deep on macOS and Linux and so is
invisible to depth.
- Credential directory names, matched against every component so both
"…/.ssh" and "…/.ssh/keys" are refused. This list is deliberately additive
so extending it needs no design authority.
A path that is or contains the cache directory is refused outright: indexing
such a tree would pull every other project's graph database into this
project's index.
Classification order is load-bearing and commented as such. The home
directory normally contains the cache directory, so testing the cache first
reported every home as "holds the cache" and made it non-overridable, which
contradicts the intent that a person may override it. Depth precedes the
cache test for the same reason: "/Users" satisfies both and "too broad" is
the reason that helps the reader.
Takes home and cache as parameters rather than reading the environment, so
the policy is a pure function and the tests need no filesystem. Twelve table
tests; three of them failed on the first implementation and drove the
ordering fix above.
Not yet wired to any caller — deliberately, so the policy can be reviewed on
its own.
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>
Martin Vogel
03e935576b