[PATCH v3 01/12] check-non-portable-shell: check for "test <cond> -a/-o <cond>"

Add a check for -a/-o in "test", as a follow-up to the
CodingGuidelines having recommended against their use since
897f964c0dc (CodingGuidelines: avoid "test <cond> -a/-o <cond>",
2014-05-20).

These constructs are considered obsolescent by POSIX[1]. GNU has
likewise warned against them[2] for a few decades.

These will only match the simplistic forms of `test -X blah` (where
"-X" is some single letter option), but will miss expressions such as
`test "$foo" = bar`. We stop at "&" or "|" to try not to overmatch
things like:

    test whatever && ls -a foo
    test whatever && foo -o outfile

1. https://pubs.opengroup.org/onlinepubs/9699919799/utilities/test.html#tag_20_128_16
2. https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.70/html_node/Limitations-of-Builtins.html

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---
 t/check-non-portable-shell.pl | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/t/check-non-portable-shell.pl b/t/check-non-portable-shell.pl
index fd3303552b..894aa0a4f9 100755
--- a/t/check-non-portable-shell.pl
+++ b/t/check-non-portable-shell.pl

@@ -41,6 +41,8 @@ sub err {
 	/^\s*declare\s+/ and err 'arrays/declare not portable';
 	/^\s*[^#]\s*which\s/ and err 'which is not portable (use type)';
 	/\btest\s+[^=]*==/ and err '"test a == b" is not portable (use =)';
+	/\btest\s+-[a-z]\s+[^&|]+\s+-a\s+/ and err '"test A && test B" preferred to "test A -a B"';
+	/\btest\s+-[a-z]\s+[^&|]+\s+-o\s+/ and err '"test A || test B" preferred to "test A -o B"';
 	/\bwc -l.*"\s*=/ and err '`"$(wc -l)"` is not portable (use test_line_count)';
 	/\bhead\s+-c\b/ and err 'head -c is not portable (use test_copy_bytes BYTES <file >out)';
 	/(?:\$\(seq|^\s*seq\b)/ and err 'seq is not portable (use test_seq)';

-- 
2.31.1.723.gf6bad1b9ba1