Fix cd environment variable expansion

[BeauDevCode]

Summary:

• Expands environment variables in the CLI cd handler before changing directories.
• Strips trailing whitespace before path expansion so CLI cd behavior matches kernel/command dispatch normalization.
• Keeps CLI cd behavior aligned with the kernel implementation.
• Adds regression coverage for env-var based cd paths and trailing-whitespace handling.

Validation:

• python -m pytest tests/test_cli_cd.py -q
• Result: 3 passed

Related issue:

• Closes duplicate cd handling, kernel and cli.py both implement cd #45

Risk:

• Low
• The change only affects cd path normalization and uses the same expandvars/expanduser order as the kernel.

[AkshajSinghal]

Before I take this out of draft:

1. Let’s get that Python 3.12 CI check green, looks like a pre-existing Windows issue, so feel free to skip those specific tests for now.
2. Add a # TODO comment in cli.py noting that we should eventually deprecate this stub in favor of the kernel dispatch to avoid duplicate logic.

Fix the CI status and add that note, and it’s good to go.

[coderabbitai]

📝 Walkthrough

Walkthrough

CLI cd path normalization now expands environment variables (in addition to ~). Two tests were added: one verifies expansion of env-var targets, the other verifies trailing whitespace after an env-var target is stripped and still resolved.

Changes

cd command environment variable expansion

Layer / File(s)	Summary
Environment variable expansion in cd command trushell/cli.py	Path expansion for cd now runs os.path.expandvars(os.path.expanduser(argument.strip())); a TODO was added noting planned deprecation of the CLI cd stub in favor of kernel dispatch.
Tests for environment-variable expansion and trailing whitespace tests/test_cli_cd.py	Adds tests: test_handle_cd_command_expands_environment_variables(...) to assert $VAR targets are expanded and test_handle_cd_command_strips_trailing_whitespace(...) to assert trailing whitespace after an env-var target is ignored.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 I sniffed the dollar-sign trail,
A hidden path in green and pale.
Expandvars hopped the gates ajar,
Now cd finds home, both near and far.
A tiny test and one small tweak — hooray, path found, hop away!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title accurately describes the main change: the CLI cd handler now expands environment variables, which aligns with the core modification in the changeset.
Linked Issues check	✅ Passed	The PR directly addresses issue #45 by implementing environment variable expansion in cli.py's _handle_cd_command using os.path.expandvars, ensuring consistent behavior with the kernel implementation and preventing silent failures for env-var paths.
Out of Scope Changes check	✅ Passed	All changes are scoped to fixing cd environment variable expansion and adding regression tests; no unrelated modifications are present.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[BeauDevCode]

Follow-up verification:

• The # TODO note exists directly above _handle_cd_command in trushell/cli.py, calling out eventual deprecation in favor of kernel dispatch to avoid duplicate path logic.
• python -m pytest tests/test_cli_cd.py -q passes locally: 2 passed.
• gh pr checks currently reports only the CodeRabbit draft-status check as passing; I do not see a failing Python 3.12 CI check exposed on this PR right now, so I did not make any workflow/test-selection changes.

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@trushell/cli.py`:
- Line 287: Trailing whitespace on the parsed argument causes inconsistent path
expansion; update the target computation to strip whitespace from the variable
argument before calling os.path.expanduser/expandvars so it matches kernel and
commands behavior (see _split_command which can leave trailing spaces) — change
the logic that assigns target (currently using argument) to use a stripped
argument, ensuring the existing check that uses argument.strip() remains
consistent with this expansion.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 53ee447b-7803-42d9-bc42-b3c7507c119c

📥 Commits

Reviewing files that changed from the base of the PR and between 8fdfbed and 4e6c584.

📒 Files selected for processing (2)

• tests/test_cli_cd.py
• trushell/cli.py