huskies: merge 618_story_extract_mcp_only_domain_services

server/src/service/shell/io.rs

@@ -0,0 +1,64 @@
+//! Shell I/O — the ONLY place in `service::shell/` that may perform side effects.
+//!
+//! Side effects here include: filesystem existence and canonicalization checks,
+//! process spawning via `std::process::Command`, and reading pipe output.
+//! All pure logic (pattern matching, output truncation, count parsing) lives in
+//! `path_guard.rs`.
+
+use super::Error;
+use std::path::{Path, PathBuf};
+
+/// Validate that `working_dir` is an absolute path that exists on disk and
+/// lies inside the project's `.huskies/worktrees/` or `.huskies/merge_workspace/`
+/// directory. Returns the canonicalized path on success.
+///
+/// # Errors
+/// - [`Error::Validation`] if the path is relative or does not exist.
+/// - [`Error::PathNotAllowed`] if the path is outside the allowed roots.
+/// - [`Error::Io`] if canonicalization fails.
+pub fn validate_working_dir(working_dir: &str, project_root: &Path) -> Result<PathBuf, Error> {
+    let wd = PathBuf::from(working_dir);
+
+    if !wd.is_absolute() {
+        return Err(Error::Validation(
+            "working_dir must be an absolute path".to_string(),
+        ));
+    }
+    if !wd.exists() {
+        return Err(Error::Validation(format!(
+            "working_dir does not exist: {working_dir}"
+        )));
+    }
+
+    let worktrees_root = project_root.join(".huskies").join("worktrees");
+
+    let canonical_wd = wd
+        .canonicalize()
+        .map_err(|e| Error::Io(format!("Cannot canonicalize working_dir: {e}")))?;
+
+    let canonical_wt = if worktrees_root.exists() {
+        worktrees_root
+            .canonicalize()
+            .map_err(|e| Error::Io(format!("Cannot canonicalize worktrees root: {e}")))?
+    } else {
+        return Err(Error::PathNotAllowed(
+            "No worktrees directory found in project".to_string(),
+        ));
+    };
+
+    // Also allow the merge workspace so mergemaster can fix conflicts.
+    let merge_workspace = project_root.join(".huskies").join("merge_workspace");
+    let canonical_mw = merge_workspace.canonicalize().unwrap_or_default();
+
+    let in_worktrees = canonical_wd.starts_with(&canonical_wt);
+    let in_merge_ws =
+        !canonical_mw.as_os_str().is_empty() && canonical_wd.starts_with(&canonical_mw);
+
+    if !in_worktrees && !in_merge_ws {
+        return Err(Error::PathNotAllowed(format!(
+            "working_dir must be inside .huskies/worktrees/ or .huskies/merge_workspace/. Got: {working_dir}"
+        )));
+    }
+
+    Ok(canonical_wd)
+}