On Thu, May 09 2019, Eric Sunshine wrote:
> For thoroughness when checking for one-shot environment variable
> assignments at shell function call sites, check-non-portable-shell
> stitches together incomplete lines (those ending with backslash). This
> allows it to correctly flag such undesirable usage even when the
> variable assignment and function call are split across lines, for
> example:
>
> FOO=bar \
> func
>
> where 'func' is a shell function.
>
> The stitching is accomplished like this:
>
> while (<>) {
> chomp;
> # stitch together incomplete lines (those ending with "\")
> while (s/\\$//) {
> $_ .= readline;
> chomp;
> }
> # detect unportable/undesirable shell constructs
> ...
> }
>
> Although this implementation is well supported in reasonably modern Perl
> versions (5.10 and later), it fails in a couple ways with older versions
> (such as Perl 5.8 shipped with ancient Mac OS 10.5).
>
> In particular, in older Perl versions, 'readline' is not connected to
> the file handle associated with the "magic" while (<>) {...} construct,
> so 'readline' throws a "readline() on unopened filehandle" error.
> Furthermore, $_ assigned by the outer while-loop is read-only, so the
> attempt to modify it via "$_ .= readline" in the inner while-loop fails
> with a "Modification of a read-only value" error.
>
> Avoid both problems by collecting the stitched-together line in a
> variable other than $_ and dropping the inner loop entirely.
>
> Signed-off-by: Eric Sunshine <[email protected]>
> ---
> t/check-non-portable-shell.pl | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/t/check-non-portable-shell.pl b/t/check-non-portable-shell.pl
> index 166d64d4a2..60e607ba42 100755
> --- a/t/check-non-portable-shell.pl
> +++ b/t/check-non-portable-shell.pl
> @@ -27,14 +27,14 @@ sub err {
> close $f;
> }
>
> +my $line = '';
> while (<>) {
> chomp;
> + $line .= $_;
> # stitch together incomplete lines (those ending with "\")
> - while (s/\\$//) {
> - $_ .= readline;
> - chomp;
> - }
> + next if $line =~ s/\\$//;
>
> + local $_ = $line;
> /\bcp\s+-a/ and err 'cp -a is not portable';
> /\bsed\s+-[^efn]\s+/ and err 'sed option not portable (use only -n, -e,
> -f)';
> /\becho\s+-[neE]/ and err 'echo with option is not portable (use
> printf)';
> @@ -48,6 +48,7 @@ sub err {
> /\bexport\s+[A-Za-z0-9_]*=/ and err '"export FOO=bar" is not portable
> (use FOO=bar && export FOO)';
> /^\s*([A-Z0-9_]+=(\w+|(["']).*?\3)\s+)+(\w+)/ and exists($func{$4}) and
> err '"FOO=bar shell_func" assignment extends beyond
> "shell_func"';
> + $line = '';
> # this resets our $. for each file
> close ARGV if eof;
> }
This fix is fine, but just for the record: There's no problem with
assigning to $_, it just throws an error about $_ *because* of the
readline() issue, i.e. it'll fail, clobber $_ to a read-only value, and
off we go.
So just assigning to $_ is fine, and you don't need to localize it.
Anyway, I tested this on 5.8, it works, then looked at the output and
wondered if I could improve it, came up with this:
diff --git a/t/check-non-portable-shell.pl b/t/check-non-portable-shell.pl
index 60e607ba42..d5fd0a3050 100755
--- a/t/check-non-portable-shell.pl
+++ b/t/check-non-portable-shell.pl
@@ -8,13 +8,26 @@
my $exit_code=0;
my %func;
+my $start_nr = 0;
+my $line = '';
sub err {
my $msg = shift;
- s/^\s+//;
- s/\s+$//;
- s/\s+/ /g;
- print "$ARGV:$.: error: $msg: $_\n";
+ if (/\n/) {
+ $. = $start_nr;
+ my ($ws) = $_ =~ /^(\s+)/;
+ for (split /^/) {
+ s/^\Q$ws\E//;
+ print "$ARGV:$.: error: $msg: $_";
+ $.++;
+ }
+ print "\n";
+ } else {
+ s/^\s+//;
+ s/\s+$//;
+ s/\s+/ /g;
+ print "$ARGV:$.: error: $msg: $_\n";
+ }
$exit_code = 1;
}
@@ -27,14 +40,16 @@ sub err {
close $f;
}
-my $line = '';
while (<>) {
chomp;
- $line .= $_;
# stitch together incomplete lines (those ending with "\")
- next if $line =~ s/\\$//;
-
- local $_ = $line;
+ if (s/\\$//) {
+ $start_nr ||= $.;
+ $line .= "$_\n";
+ next;
+ } else {
+ $_ = $line . $_;
+ }
/\bcp\s+-a/ and err 'cp -a is not portable';
/\bsed\s+-[^efn]\s+/ and err 'sed option not portable (use only -n, -e,
-f)';
/\becho\s+-[neE]/ and err 'echo with option is not portable (use
printf)';
@@ -48,7 +63,11 @@ sub err {
/\bexport\s+[A-Za-z0-9_]*=/ and err '"export FOO=bar" is not portable
(use FOO=bar && export FOO)';
/^\s*([A-Z0-9_]+=(\w+|(["']).*?\3)\s+)+(\w+)/ and exists($func{$4}) and
err '"FOO=bar shell_func" assignment extends beyond
"shell_func"';
+
+ # No longer spanning lines
+ $start_nr = 0;
$line = '';
+
# this resets our $. for each file
close ARGV if eof;
}
diff --git a/t/t0000-basic.sh b/t/t0000-basic.sh
index c03054c538..b4af7032ad 100755
--- a/t/t0000-basic.sh
+++ b/t/t0000-basic.sh
@@ -156,8 +156,11 @@ test_expect_success 'pretend we have a fully passing
test suite' "
"
test_expect_success 'pretend we have a partially passing test suite' "
- test_must_fail run_sub_test_lib_test \
- partial-pass '2/3 tests passing' <<-\\EOF &&
+ test_must_fail penis run_sub_test_lib_test \
+ partial-pass '2/3 tests passing' <<-\\EOF \
+ partial-pass '2/3 tests passing' <<-\\EOF \
+ partial-pass '2/3 tests passing' <<-\\EOF \
+ cp -a hi there &&
test_expect_success 'passing test #1' 'true'
test_expect_success 'failing test #2' 'false'
test_expect_success 'passing test #3' 'true'
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index 1f462204ea..a25ac208e5 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -122,6 +122,7 @@ test_expect_success 'plain bare with GIT_WORK_TREE' '
test_expect_success 'GIT_DIR bare' '
mkdir git-dir-bare.git &&
+ cp -a foo bar &&
GIT_DIR=git-dir-bare.git git init &&
check_config git-dir-bare.git true unset
'
I.e. now for these multi-line issues we'll print the whole offending
multi-line invocation
$ ~/g/perl/miniperl -I ~/g/perl/lib check-non-portable-shell.pl t[0-9]*.sh
t0000-basic.sh:159: error: cp -a is not portable: test_must_fail penis
run_sub_test_lib_test
t0000-basic.sh:160: error: cp -a is not portable: partial-pass '2/3
tests passing' <<-\\EOF
t0000-basic.sh:161: error: cp -a is not portable: partial-pass '2/3
tests passing' <<-\\EOF
t0000-basic.sh:162: error: cp -a is not portable: partial-pass '2/3
tests passing' <<-\\EOF
t0000-basic.sh:163: error: cp -a is not portable: cp -a hi there &&
t0001-init.sh:125: error: cp -a is not portable: cp -a foo bar &&
I figured it was better than the current output just squashing such a
long line together, i.e. it'll print this now (before/after this patch):
$ ~/g/perl/miniperl -I ~/g/perl/lib check-non-portable-shell.pl t[0-9]*.sh
t0000-basic.sh:163: error: cp -a is not portable: test_must_fail penis
run_sub_test_lib_test partial-pass '2/3 tests passing' <<-\\EOF partial-pass
'2/3 tests passing' <<-\\EOF partial-pass '2/3 tests passing' <<-\\EOF cp -a hi
there &&
t0001-init.sh:125: error: cp -a is not portable: cp -a foo bar &&
There's ways to make that WIP patch shorter etc. I wasn't trying to golf
it, also I think we can get rid of that s/\s+$// if we split up lines
like this.
