CVS commit: src/bin/sh

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

Module Name:    src
Committed By:   kre
Date:           Sat Apr 18 14:35:37 UTC 2026

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

Log Message:
Remove CHECKSTACKSTR() defect workaround

When reading the output from a command substitution, the code defers
adding embedded \n's to the result (just counting them instead) until
some other character appears - this effectively achieves the "trailing
\n's are removed" semantic without needing to actually remove anything,
as without a following char, the \n's aren't ever added.

That's fine, but the number of \n's counted, that will need to be added when
another char appears, is unbounded - and could be (and at least once, was)
more than the old CHECKSTACKSTR() could handle.  To fix that, if the newline
count was "too big" (arbitrarily set at 20) the code used a slow path, which
avoided CHECKSTACKSTR() and was correct.

Now CHECKSTACKSTR() has been fixed, that workaround is no longer required,
so remove it.   Since long runs of embedded \n's don't often appear in
command substitution output, avoiding the slow path is unlikely to make
any noticeable speed difference, but not having that code at all makes the
shell smaller - enough smaller to compensate for the minor increase that
the CHECKSTACKSTR() correction added, and even a bit more.


To generate a diff of this commit:
cvs rdiff -u -r1.150 -r1.151 src/bin/sh/expand.c

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