t/check-non-portable-shell: detect "FOO=bar shell_func"

One-shot environment variable assignments, such as 'FOO' in
"FOO=bar cmd", exist only during the invocation of 'cmd'. However, if
'cmd' happens to be a shell function, then 'FOO' is assigned in the
executing shell itself, and that assignment remains until the process
exits (unless explicitly unset). Since this side-effect of
"FOO=bar shell_func" is unlikely to be intentional, detect and report
such usage.

To distinguish shell functions from other commands, perform a pre-scan
of shell scripts named as input, gleaning a list of function names by
recognizing lines of the form (loosely matching whitespace):

    shell_func () {

and later report suspect lines of the form (loosely matching quoted
values):

    FOO=bar [BAR=foo ...] shell_func

Also take care to stitch together incomplete lines (those ending with
"\") since suspect invocations may be split over multiple lines:

    FOO=bar BAR=foo \
    shell_func

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/check-non-portable-shell.pl b/t/check-non-portable-shell.pl
index f6dbe28b19c25e1828b4441754a8b2ffcbfd18ac..d5823f71d8d57ec92404d5cceabd86d5ab86af53 100755 (executable)
--- a/t/check-non-portable-shell.pl
+++ b/t/check-non-portable-shell.pl
@@ -7,17 +7,34 @@ use strict;
 use warnings;
 
 my $exit_code=0;
+my %func;
 
 sub err {
        my $msg = shift;
        s/^\s+//;
        s/\s+$//;
+       s/\s+/ /g;
        print "$ARGV:$.: error: $msg: $_\n";
        $exit_code = 1;
 }
 
+# glean names of shell functions
+for my $i (@ARGV) {
+       open(my $f, '<', $i) or die "$0: $i: $!\n";
+       while (<$f>) {
+               $func{$1} = 1 if /^\s*(\w+)\s*\(\)\s*{\s*$/;
+       }
+       close $f;
+}
+
 while (<>) {
        chomp;
+       # stitch together incomplete lines (those ending with "\")
+       while (s/\\$//) {
+               $_ .= readline;
+               chomp;
+       }
+
        /\bsed\s+-i/ and err 'sed -i is not portable';
        /\becho\s+-[neE]/ and err 'echo with option is not portable (use printf)';
        /^\s*declare\s+/ and err 'arrays/declare not portable';
@@ -25,6 +42,8 @@ while (<>) {
        /\btest\s+[^=]*==/ and err '"test a == b" is not portable (use =)';
        /\bwc -l.*"\s*=/ and err '`"$(wc -l)"` is not portable (use test_line_count)';
        /\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"';
        # this resets our $. for each file
        close ARGV if eof;
 }