CodingGuidelines: quote assigned value in 'local var=$val'
Dash bug https://bugs.launchpad.net/ubuntu/+source/dash/+bug/139097 lets the shell erroneously perform field splitting on the expansion of a command substitution during declaration of a local or an extern variable. The explanation was stolen from ebee5580 (parallel-checkout: avoid dash local bug in tests, 2021-06-06). Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano committed
Apr 5, 2024 at 17:08 UTC
be34b51049d1628d1ba4f17e3c087fd01f15f988
1 file changed
+12
Documentation/CodingGuidelines
+12
index 96eaeee205..30bf290418 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines
@@ -192,6 +192,18 @@ For shell scripts specifically (not exhaustive):
so we write "variable=value" and then "export variable" on two
separate lines.
+ - Some versions of dash have broken variable assignment when prefixed
+ with "local", "export", and "readonly", in that the value to be
+ assigned goes through field splitting at $IFS unless quoted.
+
+ (incorrect)
+ local variable=$value
+ local variable=$(command args)
+
+ (correct)
+ local variable="$value"
+ local variable="$(command args)"
+
- Use octal escape sequences (e.g. "\302\242"), not hexadecimal (e.g.
"\xc2\xa2") in printf format strings, since hexadecimal escape
sequences are not portable.