fix: introduce AbsolutePathBuf as part of sandbox config (#7856)

Changes the `writable_roots` field of the `WorkspaceWrite` variant of
the `SandboxPolicy` enum from `Vec<PathBuf>` to `Vec<AbsolutePathBuf>`.
This is helpful because now callers can be sure the value is an absolute
path rather than a relative one. (Though when using an absolute path in
a Seatbelt config policy, we still have to _canonicalize_ it first.)

Because `writable_roots` can be read from a config file, it is important
that we are able to resolve relative paths properly using the parent
folder of the config file as the base path.

codex-rs/utils/absolute-path/src/lib.rs

@@ -1,4 +1,5 @@
 use path_absolutize::Absolutize;
+use schemars::JsonSchema;
 use serde::Deserialize;
 use serde::Deserializer;
 use serde::Serialize;
@@ -7,6 +8,7 @@ use std::cell::RefCell;
 use std::path::Display;
 use std::path::Path;
 use std::path::PathBuf;
+use ts_rs::TS;
 
 /// A path that is guaranteed to be absolute and normalized (though it is not
 /// guaranteed to be canonicalized or exist on the filesystem).
@@ -15,27 +17,27 @@ use std::path::PathBuf;
 /// using `AbsolutePathBufGuard::new(base_path)`. If no base path is set, the
 /// deserialization will fail unless the path being deserialized is already
 /// absolute.
-#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, JsonSchema, TS)]
 pub struct AbsolutePathBuf(PathBuf);
 
 impl AbsolutePathBuf {
-    pub fn resolve_path_against_base<P, B>(path: P, base_path: B) -> std::io::Result<Self>
-    where
-        P: AsRef<Path>,
-        B: AsRef<Path>,
-    {
+    pub fn resolve_path_against_base<P: AsRef<Path>, B: AsRef<Path>>(
+        path: P,
+        base_path: B,
+    ) -> std::io::Result<Self> {
         let absolute_path = path.as_ref().absolutize_from(base_path.as_ref())?;
         Ok(Self(absolute_path.into_owned()))
     }
 
-    pub fn from_absolute_path<P>(path: P) -> std::io::Result<Self>
-    where
-        P: AsRef<Path>,
-    {
+    pub fn from_absolute_path<P: AsRef<Path>>(path: P) -> std::io::Result<Self> {
         let absolute_path = path.as_ref().absolutize()?;
         Ok(Self(absolute_path.into_owned()))
     }
 
+    pub fn join<P: AsRef<Path>>(&self, path: P) -> std::io::Result<Self> {
+        Self::resolve_path_against_base(path, &self.0)
+    }
+
     pub fn as_path(&self) -> &Path {
         &self.0
     }
@@ -48,11 +50,59 @@ impl AbsolutePathBuf {
         self.0.clone()
     }
 
+    pub fn to_string_lossy(&self) -> std::borrow::Cow<'_, str> {
+        self.0.to_string_lossy()
+    }
+
     pub fn display(&self) -> Display<'_> {
         self.0.display()
     }
 }
 
+impl AsRef<Path> for AbsolutePathBuf {
+    fn as_ref(&self) -> &Path {
+        &self.0
+    }
+}
+
+impl From<AbsolutePathBuf> for PathBuf {
+    fn from(path: AbsolutePathBuf) -> Self {
+        path.into_path_buf()
+    }
+}
+
+impl TryFrom<&Path> for AbsolutePathBuf {
+    type Error = std::io::Error;
+
+    fn try_from(value: &Path) -> Result<Self, Self::Error> {
+        Self::from_absolute_path(value)
+    }
+}
+
+impl TryFrom<PathBuf> for AbsolutePathBuf {
+    type Error = std::io::Error;
+
+    fn try_from(value: PathBuf) -> Result<Self, Self::Error> {
+        Self::from_absolute_path(value)
+    }
+}
+
+impl TryFrom<&str> for AbsolutePathBuf {
+    type Error = std::io::Error;
+
+    fn try_from(value: &str) -> Result<Self, Self::Error> {
+        Self::from_absolute_path(value)
+    }
+}
+
+impl TryFrom<String> for AbsolutePathBuf {
+    type Error = std::io::Error;
+
+    fn try_from(value: String) -> Result<Self, Self::Error> {
+        Self::from_absolute_path(value)
+    }
+}
+
 thread_local! {
     static ABSOLUTE_PATH_BASE: RefCell<Option<PathBuf>> = const { RefCell::new(None) };
 }
@@ -96,18 +146,6 @@ impl<'de> Deserialize<'de> for AbsolutePathBuf {
     }
 }
 
-impl AsRef<Path> for AbsolutePathBuf {
-    fn as_ref(&self) -> &Path {
-        self.as_path()
-    }
-}
-
-impl From<AbsolutePathBuf> for PathBuf {
-    fn from(path: AbsolutePathBuf) -> Self {
-        path.into_path_buf()
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;