`.abcd/development/brief/04-surfaces/17-guard.md:1044`: The chapter lists same-line carried values as unseen and calls the matter an open ruling, but they block and the ruling is made. All block when the value is assigned on the line (`X='rm -rf /'; eval "$X"`, `P=pkill; $P make`). The ruling is made: internal/core/guard/carried.go cites it, and iss-2609281134544802 is in .abcd/work/issues/resolved/.

Frontmatter

.abcd/work/issues/open/iss-2611060810026397-abcd-development-brief-04-surfaces.md
open on GitHub ↗ · commit history ↗

mentions1

• iss-2609281134544802The shell guard reads a parameter expansion as an unknown word (iss-2609251824244354, lane drainG3) for the flags and program names its value can spell, but not as data an earlier command carried into the variable, and four classes stay unread: (1) a pid list a search printed into a variable (p=$(pgrep make); kill $p, or pgrep make | while read p; do kill $p; done), the plain-variable half [dcn-2609250000000016](../../decisions/dcn-2609250000000016-correction-to-the-two-entries-above-on.md) (c) parked on iss-2609251824244354; (2) a stream path in a variable handed to a shell or source as its script (bash "$f" after f=<(curl ...)); (3) shell text a variable holds, run through eval "$X", sh -c "$X", or placed in a string a shell runs, whose value may hold a separator or quotes (eval "$X" allows, as it did before the reading); (4) pkill or killall as a variable's value standing as the program with an operand ($P make), and a variable-named bare interpreter inside a string. Reading each would refuse ordinary commands: the false-positive sweep of 4,315 inputs showed 22 new program-name-unknown blocks ("$GO" build, exec "$BIN", $EDITOR notes.md) and 15 new interpreter-reads-stream blocks (bash "$SCRIPT") before these readings were left out. Classes 1 and 3 carry the same cost, from the sweep's everyday-variable lines, each of which allows today: a reading of class 1 cannot tell a pid a search printed from one the script recorded, so it would refuse kill "$pid", kill -TERM "$PID" and kill -- -"$pg" (a background job's pid, a pidfile's, a process group's); a reading of class 3 cannot tell a hostile string from a composed one, so it would refuse eval "$cmd", the line that runs a command a script built up. Each class is a block, warn or allow call the product thinker has not ruled on.