## Why
`PathUri::from_abs_path` can fail for absolute paths that do not have a
normal `file:` URI representation, forcing filesystem call sites to
handle a conversion error even though the original path can be preserved
losslessly.
## What
Make `from_abs_path` infallible and migrate its callers. Unrepresentable
paths use `file:///%00/bad/path/<base64>`, encoding Unix bytes or
Windows UTF-16LE; `to_abs_path` validates and decodes that fallback. The
leading encoded null reserves a namespace that cannot collide with a
real Unix or Windows path, and fallback URIs remain opaque to lexical
path operations.
## Validation
Added path-URI coverage for Unix null and non-UTF-8 paths, Windows
device/verbatim and non-Unicode paths, serialization, malformed
fallbacks, opaque lexical operations, invalid native payloads, and
literal `/bad/path` collision resistance.
## Why
Codex needs stable `file:` URI identifiers that can cross process and
operating-system boundaries without eagerly interpreting them as native
paths. Existing fields also need to keep accepting absolute path strings
during migration.
## What changed
- Add `codex-utils-path-uri` with a validated, immutable `PathUri`
wrapper that currently accepts only `file:` URLs.
- Expose URI-level `basename`, `parent`, and `join` operations that
preserve authorities and percent encoding without guessing the source
operating system.
- Keep native conversion explicit through `AbsolutePathBuf` and the
current host rules.
- Serialize as canonical URI text while accepting both URI text and
legacy absolute native paths during deserialization.
- Add adversarial coverage for Windows-looking and POSIX paths, UNC
authorities, encoded metadata characters, non-UTF-8 POSIX paths, URI
hierarchy operations, and legacy serde round trips.
Adam Perry @ OpenAI ·