Bash permission walker reports "Unhandled node type: ;" and forces prompt on subshell-form commands

Summary

Claude Code's Bash permission evaluator walks the tree-sitter-bash AST of each
command to match it against the allow-list. The walker is missing a handler for
the ; node type emitted between statements inside a subshell body, so any
command of the form (cmd1; cmd2) produces Unhandled node type: ; and is
forced to a manual approval prompt even when both inner commands would otherwise
be auto-allowed.

Minimal reproduction

With Bash(cd:*) and Bash(ls:*) (or equivalent) on the allow-list:

(cd /tmp; ls)

Result: Unhandled node type: ; is shown to the user and an approval prompt
appears, despite both cd /tmp and ls being individually allow-listed.

Why this matters

The two-call form (cd <path> in one Bash call, then bare commands in
subsequent calls) relies on CWD persisting across tool calls. That works in the
main agent but not in subagents — each subagent Bash call resets to the
agent's CWD. The documented alternative for subagents is the subshell form
(cd <abs-path>; <command>), which avoids the CVE-2025-59536 harness gate on
cd <path> && <cmd>. With ; unhandled by the walker, the subshell form also
forces a prompt, leaving subagents with no auto-approvable form for
"run X inside this directory."

Related walker bugs

Same family — walker missing handlers for specific tree-sitter-bash node types,
diagnostic leaking to user output:

• #47701 — \file_redirect\ (\>\, \>>\, \2>&1\, heredocs)
• #47706 — the diagnostic leaking to user output at all
• #42085 — \string\ (for \\$(...)\ and backticks; regression in 2.1.89)
• #49483 — trailing \\$\
• #50144 — \string\ from MCP results

Suggested fix

Add a handler for the \;\ node type in the walker (treat as a statement
separator, recurse into both children). Same shape as the fix that would unblock
\&&\ / \||\ / \|\ inside subshells if they have the same gap.

Environment

• Claude Code (CLI), macOS (Darwin 25.4.0)
• Shell: zsh 5.9