From: Junio C Hamano <gitster@pobox.com>
To: git@vger.kernel.org
Subject: [PATCH 2/6] CodingGuidelines: quote assigned value in 'local var=$val'
Date: Fri, 5 Apr 2024 17:08:58 -0700 [thread overview]
Message-ID: <20240406000902.3082301-3-gitster@pobox.com> (raw)
In-Reply-To: <20240406000902.3082301-1-gitster@pobox.com>
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>
---
Documentation/CodingGuidelines | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
index 0a39205c48..1cb77a871b 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines
@@ -194,6 +194,20 @@ For shell scripts specifically (not exhaustive):
have changed since then. We'd need to re-evaluate this rule,
together with the rule in t/check-non-portable-shell.pl script.
+ - 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 $IFS unless quoted.
+
+ DO NOT write:
+
+ local variable=$value ;# wrong
+ local variable=$(command args) ;# wrong
+
+ and instead write:
+
+ local variable="$value"
+ local variable="$(command args)"
+
- Use octal escape sequences (e.g. "\302\242"), not hexadecimal (e.g.
"\xc2\xa2") in printf format strings, since hexadecimal escape
sequences are not portable.
--
2.44.0-501-g19981daefd
next prev parent reply other threads:[~2024-04-06 0:09 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-06 0:08 [PATCH 0/6] local VAR="VAL" Junio C Hamano
2024-04-06 0:08 ` [PATCH 1/6] CodingGuidelines: describe "export VAR=VAL" rule Junio C Hamano
2024-04-06 5:11 ` Eric Sunshine
2024-04-06 5:47 ` Junio C Hamano
2024-04-06 9:15 ` Andreas Schwab
2024-04-06 17:03 ` Junio C Hamano
2024-04-06 17:34 ` Eric Sunshine
2024-04-06 0:08 ` Junio C Hamano [this message]
2024-04-06 1:29 ` [PATCH 2/6] CodingGuidelines: quote assigned value in 'local var=$val' rsbecker
2024-04-06 2:29 ` Junio C Hamano
2024-04-06 5:16 ` Eric Sunshine
2024-04-06 5:40 ` Junio C Hamano
2024-04-06 0:08 ` [PATCH 3/6] t: local VAR="VAL" (quote positional parameters) Junio C Hamano
2024-04-08 15:30 ` Patrick Steinhardt
2024-04-08 17:23 ` Junio C Hamano
2024-04-06 0:09 ` [PATCH 4/6] t: local VAR="VAL" (quote command substitution) Junio C Hamano
2024-04-06 0:09 ` [PATCH 5/6] t: local VAR="VAL" (quote ${magic-reference}) Junio C Hamano
2024-04-06 0:09 ` [PATCH 6/6] t: teach lint that RHS of 'local VAR=VAL' needs to be quoted Junio C Hamano
2024-04-07 1:43 ` Jeff King
2024-04-08 17:31 ` Junio C Hamano
2024-04-08 20:40 ` Jeff King
2024-04-06 0:23 ` [PATCH 7/6] t0610: local VAR="VAL" fix Junio C Hamano
2024-04-06 0:28 ` [PATCH 8/6] t1016: " Junio C Hamano
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