yoi/work-items/open/20260531-104614-pure-path-fallback-tests/thread.md

Created

Created by tickets.sh create.

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Plan

Preflight classification: implementation-ready.

Intent:

• Remove unnecessary process-global environment mutation from path fallback tests by making the fallback/precedence logic directly testable with explicit inputs.

Requirements:

• Start with manifest::paths, where path resolution is centralized and currently owns env fallback tests.
• Use small per-key pure helpers with direct optional path inputs. Do not introduce a general PathEnv, EnvSnapshot, env trait, or test-support crate.
• Keep public runtime behavior unchanged: the production wrappers still read the same env vars, ignore empty path env values as before, and resolve the same fallback order.
• Keep docs/environment.md behavior aligned with code.

Current code map:

• crates/manifest/src/paths.rs: core config/data/runtime/resource path resolution and env fallback tests using local EnvGuard.
• docs/environment.md: documented fallback order for home/config_dir/data_dir/runtime_dir/resource_dir.
• Other env mutations in pod/pod-registry are mostly subprocess/runtime-isolation integration setup and should not be force-fixed in this ticket.
• Provider credential env mutation belongs to manifest-profile-encrypted-secrets, not this ticket.

Critical risks:

• Accidentally changing path precedence while making tests pure.
• Creating an over-broad abstraction that keeps env mutation around indirectly.
• Treating spawned-process runtime isolation env setup as equivalent to pure fallback tests and breaking integration tests.

Intent packet for implementation:

Intent:

• Make manifest::paths fallback tests pure and independent from process env mutation.

Requirements:

• Extract narrow pure helper functions for fallback precedence.
• Convert fallback-order tests to call those helpers directly.
• Keep production path functions and documented behavior unchanged.
• Do not introduce a new crate, PathEnv struct, env trait, or test-only env var.

Invariants:

• Path authority remains in manifest::paths.
• No new environment-variable surface.
• No provider credential/env cleanup in this ticket.
• No Pod runtime/process model changes.

Non-goals:

• Eliminating all set_var/remove_var in the repository.
• Reworking resource packaging lookup beyond preserving behavior.

Escalate if:

• Removing env mutation requires changing public APIs or path semantics.
• Resource lookup behavior is ambiguous enough to need a product decision.
• Pod runtime integration tests appear to need broader runtime-dir API changes.

Validation:

• cargo fmt --check
• cargo test -p manifest paths
• relevant additional manifest tests if names differ
• cargo check -p manifest
• ./tickets.sh doctor
• git diff --check
• report remaining set_var/remove_var in touched areas and why they remain, if any.

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