fix(stella-cli): let the witness author name the candidate root in glob

[macanderson]

What & why

Refs #1792, #1813.

The review bot flagged this on #1813 (witness_tools.rs:200) and it merged before the thread was answered, so the defect is on main now.

The witness author's glob guard refuses the tool's own default argument. crates/stella-tools/src/glob.rs documents and implements the root two ways:

"path": { "type": "string", "description": "Subdirectory to search (default: workspace root)" }
...
let search_path = input.get("path").and_then(|v| v.as_str()).unwrap_or(".");
// `.`/empty resolve to the root itself, so existing default-scoped calls keep working.

But WitnessToolExecutor gated path on normalized_candidate_path, which answers None for both:

• "" → the is_empty() guard
• "." → the CurDir component is dropped, parts ends up empty, and (!parts.is_empty()).then(...) yields None

So a model that spells the default out loud — which they routinely do — is told "the path must stay within the candidate root" about the root itself. That is the blind author's opening move, and the whole reason glob was offered to it in #1792.

The root cause

normalized_candidate_path's None conflates two different answers: "escapes the root" and "is the root". That is correct for read_file, which was what it was written for — a path naming no file is simply not readable. It is wrong for a listing tool, where the root is the most ordinary argument there is.

names_candidate_root answers the second question separately. It rules out absolute and drive-qualified spellings first, so / — which would otherwise trim to the empty string and look like the root — stays an escape.

The witness

• This PR includes a witness test (fails on main, passes here).

candidate_ws::witness_tools::tests::glob_accepts_the_root_spelled_out_as_well_as_omitted, checked the artisanal way:

panicked at crates/stella-cli/src/candidate_ws/witness_tools.rs:655:17:
`path: "."` names the root and must be allowed: Error { message:
"`glob` is not available to the witness author: the path must stay within the candidate root" }
test result: FAILED. 0 passed; 1 failed

It asserts both directions: ., "", ./ are allowed and actually search the root; /, .., ../.., /etc are still refused.

Why the existing test did not catch it: glob_lets_the_author_discover_tests_without_leaking_credentials only ever passes no path (exercising the tool's own default, which never reaches the guard) or an escaping one. The explicit-root case sat exactly in the gap between them.

The gate

• cargo fmt --check -p stella-cli
• cargo test -p stella-cli — 1421 pass, 0 fail

Nothing left behind

• There is nothing: everything I noticed is fixed in this PR.

Summary by Sourcery

Allow the witness glob tool to treat explicit root paths as valid while still denying paths that escape the candidate workspace.

Bug Fixes:

• Fix glob witness tool incorrectly rejecting explicit root paths such as "." or "" that should resolve to the workspace root.

Enhancements:

• Introduce a helper to detect when a path names the candidate root, distinguishing it from paths that escape the root.

Tests:

• Add a witness test verifying that glob accepts explicit root spellings and continues to refuse paths that leave the candidate root.

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
stella-cli-docs	Ignored		Aug 6, 2026 10:54am

[sourcery-ai]

Reviewer's Guide

Adjusts the glob witness tool path guard so that explicit root spellings are accepted while still rejecting escaping paths, by introducing a dedicated root-detection helper and adding regression tests.

File-Level Changes

Change	Details	Files
Relax glob path guard to allow explicit root spellings while still rejecting paths that escape the candidate root.	Update the glob arm in WitnessToolExecutor to short‑circuit the denial check when the provided path names the candidate root, instead of relying solely on normalized_candidate_path returning Some. Preserve the existing behavior that denies glob calls whose path escapes the candidate root or is otherwise invalid.	crates/stella-cli/src/candidate_ws/witness_tools.rs
Introduce a helper to detect whether a user-provided path denotes the candidate root itself.	Add names_candidate_root function that normalizes separators, rejects absolute and drive-qualified paths, and treats empty, ., and ./-style spellings as naming the root. Document the separation of concerns between names_candidate_root and normalized_candidate_path, clarifying the different semantics of None for listing vs. reading tools.	crates/stella-cli/src/candidate_ws/witness_tools.rs
Add regression test to verify glob accepts explicit root spellings and still refuses escaping paths.	Create async test glob_accepts_the_root_spelled_out_as_well_as_omitted that sets up a temporary candidate workspace with a test file. Assert that glob with path values of ., "", and "./" returns results containing the root test file. Assert that glob with path values that escape or are absolute (e.g., /, .., ../.., /etc) are rejected with an error.	crates/stella-cli/src/candidate_ws/witness_tools.rs

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