CVS commit: src/bin/sh

["Robert Elz" <kre%netbsd.org@localhost>]

Module Name:    src
Committed By:   kre
Date:           Mon Oct 21 15:57:45 UTC 2024

Modified Files:
        src/bin/sh: expand.c parser.c parser.h

Log Message:
Fix processing of unknown variable expansion types.

Our shell is (was) one of the last not to do this correctly.

Expansions are supposed to happen only when the command in which
they occur is being executed, not while it is being parsed.
If the expansion only happens them, errors should only be
detected then.

Make it work like that (I saw after I fixed this that FreeBSD
had done it, long ago, almost the same way - it is kind of an
obvious thing to do).

This will allow code like

        if test it is shell X
        then
                commands using shell X specific expansion ops
        else if it is shell Y
        then
                commands using shell Y specific expansion ops
        else ...
        fi

Previously expansion errors were detected while parsing, so
if we're not shell X, and don't implement something that it
does (some extension to the standard) that would have generated
a parser syntax error, and the script could not be executed
(despite the line with the error never being executed).

Note that this change does not handle all such possible
extensions, just this one.   Others are much harder.

One side effect of this change is that sh will now continue
reading a variable expansion until it locates the terminating
'}' (in ${var} forms) regardless of how broken it obviously
is (to our shell) whereas previously it would have bailed out
as soon as an oddity was spotted.


To generate a diff of this commit:
cvs rdiff -u -r1.145 -r1.146 src/bin/sh/expand.c
cvs rdiff -u -r1.183 -r1.184 src/bin/sh/parser.c
cvs rdiff -u -r1.29 -r1.30 src/bin/sh/parser.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.