Re: [PATCH v2] parallel-checkout: avoid dash local bug in tests

René Scharfe [off-list ref] writes:

Am 05.06.21 um 21:56 schrieb Ævar Arnfjörð Bjarmason:

quoted

On Sat, Jun 05 2021, René Scharfe wrote:

quoted

-	local workers=$(grep "child_start\[..*\] git checkout--worker" "$trace_file" | wc -l) &&
-	test $workers -eq $expected_workers &&
+	test $(grep -c "child_start\[..*\] git checkout--worker" "$trace_file") -eq $expected_workers &&
 	rm "$trace_file"
 } 8>&2 2>&4

I'd find this thing much clearer if the v2 just narrowly focused on
avoiding the "local", and thus demonstrated the non-portable shell
issue,

I was not aiming for a minimal fix and I don't think the patch above is
too complex, but you're right that at this point in the release cycle a
duct-tape-style patch would be better.

Sorry for being late to the party but I tend to disagree.  "grep -c"
is used elsewhere in the tests, we know it is safe.

IOW, the above change is quite straight-forward.  It is much more
obvious and close to "duct-tape-style" fix, than some altermatives
like enclosing the whole command substitution in a pair of
double-quotes and rely on $workers always getting used without
double-quotes around it.  To me, that looks more subtle and brittle.

quoted

and perhaps with something like:

	diff --git a/t/check-non-portable-shell.pl b/t/check-non-portable-shell.pl
	index fd3303552be..aad6f3e2bf1 100755
	--- a/t/check-non-portable-shell.pl
	+++ b/t/check-non-portable-shell.pl
	@@ -48,6 +48,7 @@ sub err {
	 	/\bexport\s+[A-Za-z0-9_]*=/ and err '"export FOO=bar" is not portable (use FOO=bar && export FOO)';
	 	/^\s*([A-Z0-9_]+=(\w*|(["']).*?\3)\s+)+(\w+)/ and exists($func{$4}) and
	 		err '"FOO=bar shell_func" assignment extends beyond "shell_func"';
	+	/\blocal\b \S+=\$\(.*?\|\s*\bwc -l\)/ and err 'whitespace handling in local=$(... | wc -l) differs in some dash versions';

Any command can output whitespace, it's not limited to wc -l.  So a
better rule might be to always quote command substitutions in local
variable declarations (local foo="$(...)").  Or to disallow assignments
with local altogether, like we already do for export, but that might be
a bit much.

I actually do not mind "no assignments with local decl" that much.
I agree that is outside the scope of this particular fix.