Shell Safety: Test Command Gap Analysis / Claude Code v2.1.213

What

The Bash safety parser now checks test commands ([[ ... ]]) for unparsed bytes between children or after the last child, which would indicate the parser missed content the shell will actually see.

Details

A new recursive function dnu() walks test_command AST nodes and their four nested compound-expression node types: unary_expression, binary_expression, negated_expression, and parenthesized_expression
For each node the function tracks a byte-position cursor from startIndex to endIndex and measures the gap before each child and after the last child; gaps that contain only whitespace (spaces, tabs), backslash-newline continuations, or (in bash mode) comment characters are allowed
Between-children gap: if the bytes between two adjacent parsed children are non-trivial, the function returns { kind: "too-complex", reason: "Test command has unparsed bytes between children — parser dropped content that shell will see" }
After-last-child gap: if bytes remain between the last child's endIndex and the node's own endIndex, the function returns { kind: "too-complex", reason: "Test command has unparsed bytes after its last child — parser dropped content that shell will see" }
Child out-of-bounds: if a child's span extends outside the parent's span, the function returns { kind: "too-complex", reason: "Test command child extends past the node span — gap byte accounting is untrustworthy" }
All three cases produce a "too-complex" result; the safety classifier treats "too-complex" as inability to determine read-only status, so the command is not automatically approved — the user sees the standard "approve this command?" prompt rather than a silent pass-through
This closes a semantic gap where a tree-sitter parse failure inside [[ ]] could have caused the classifier to analyse a truncated/simplified version of the condition and incorrectly allow a command that the shell would evaluate differently

Evidence

Test command validation (search for "Test command has unparsed bytes between children", "Test command has unparsed bytes after its last child"); gap-check implementation (search for dnu, Zru, unu)

Strings lifted out of the shipped bundle, so the claim above can be checked against them.