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oneliner helper does not allow variables #355

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atoomic opened this issue Jul 20, 2020 · 11 comments · May be fixed by #356
Closed

oneliner helper does not allow variables #355

atoomic opened this issue Jul 20, 2020 · 11 comments · May be fixed by #356

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@atoomic
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atoomic commented Jul 20, 2020

When reading the unit test for the sub oneliner from t/oneliner.t

try_oneliner(q{$PATH = 'foo'; print $PATH},[], q{foo},   'dollar signs' );

You have the feeling that oneliner authorizes the usage of variables, all the most the test is passing.
But in truth it's using references:

# $(ABSPERLRUN)  -e '$$PATH = '\''foo'\''; print $$PATH' --

I wonder if we should teach sub oneliner to allow_variables when calling quote_literal, or detect incorrect usage of variable...

For example you can use %h but then it's going to fail when using $h later to access a value...

Detail:

my %h = (1..4); is a valid oneliner

$mm->oneliner( q[my %h = (1..4);]);
# $(ABSPERLRUN)  -e 'my %h = (1..4); print $$h[1]' --

but my %h = (1..4); print $h[1] is invalid

$mm->oneliner( q[my %h = (1..4);]);
# $(ABSPERLRUN)  -e 'my %h = (1..4); print $$h[1]' --

#!perl

use Test::More;

require ExtUtils::MM;

my $mm = MM->new(
	{ NAME => q[Fake], }
);

my $cmd;

# valid - using ref
my $cmd = $mm->oneliner( q[$PATH = 'foo'; print $PATH]);
note $cmd;
# $(ABSPERLRUN)  -e '$$PATH = '\''foo'\''; print $$PATH' --

# invalid
my $cmd = $mm->oneliner( q[my $PATH = 'foo'; print $PATH]);
note $cmd;
# $(ABSPERLRUN)  -e 'my $$PATH = '\''foo'\''; print $$PATH' --
@Leont
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Leont commented Jul 20, 2020

But in truth it's using references:

What are you talking about? That looks like a oneliner correctly escaped to be used in a Makefile.

@atoomic
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atoomic commented Jul 20, 2020 •
edited

$mm->oneliner( q[$PATH = 'foo'; print $PATH] ); converts to '$$PATH = '\''foo'\''; print $$PATH'
so this is working fine when not doing something else than that kind of $ usage...
$PATH is a reference and not one scalar value as we could thing

proof in image

╰─> perl -e '$$a = 42; use Devel::Peek; Dump $a; print $$a'
SV = IV(0x7f879c024f00) at 0x7f879c024f10
  REFCNT = 1
  FLAGS = (ROK)
  RV = 0x7f879c00ade0
  SV = IV(0x7f879c00add0) at 0x7f879c00ade0
    REFCNT = 1
    FLAGS = (IOK,pIOK)
    IV = 42
42%

@Leont
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Leont commented Jul 20, 2020

Given this Makefile

all:
    perl -e '$$a = 42; use Devel::Peek; Dump $$a'

Try running make

@atoomic
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atoomic commented Jul 20, 2020

Another way to show the problem is to add a simple my before $PATH = 'foo'; print $PATH
$mm->oneliner( q[my $PATH = 'foo'; print $PATH] );
which convert the code to
# $(ABSPERLRUN) -e 'my $$PATH = '\''foo'\''; print $$PATH' --
which is invalid Perl code... as shown just after

╰─> perl -e 'my $$PATH = '\''foo'\''; print $$PATH'
Can't declare scalar dereference in "my" at -e line 1, near "$PATH ="
Execution of -e aborted due to compilation errors.

@atoomic
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atoomic commented Jul 20, 2020

another example is to try one liner using a simple hash
my %h = (1 => 2); print $h{1};
will then convert to
# $(ABSPERLRUN) -e 'my %h = (1 => 2); print $$h{1}; ' --
which is not running what we think should run

@Leont Leont closed this as completed Jul 20, 2020
@Grinnz
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Grinnz commented Jul 20, 2020

As @Leont said this is not generating Perl code, it is generating Perl code escaped for use in a Makefile.

@atoomic
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atoomic commented Jul 20, 2020

Thanks for the clarification, once used in a Makefile, there is no issue.

Unfortunately the unit test t/oneliner.t is not consuming it via a Makefile, which explains the confusion.

view https://github.com/Perl-Toolchain-Gang/ExtUtils-MakeMaker/blob/master/t/oneliner.t#L33

@mohawk2
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mohawk2 commented Jul 21, 2020

@atoomic You are asserting as fact that perl -E 'say $$x' in a Makefile recipe ends up as dereferencing a scalar. Read the documentation for make and how it interprets $ in its recipes.

@mohawk2
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mohawk2 commented Jul 21, 2020

The oneliner function is only supposed to produce things for use in a Makefile. Surely this is not that baffling an idea in a module called "MakeMaker".

atoomic added a commit to atoomic/ExtUtils-MakeMaker that referenced this issue Jul 21, 2020
@atoomic
Test oneliner without double escaping dollar sign
5b7bb4a 
Fix Perl-Toolchain-Gang#355
atoomic added a commit to atoomic/ExtUtils-MakeMaker that referenced this issue Jul 21, 2020
@atoomic
Test oneliner without double escaping dollar sign
253de6b 
Fix Perl-Toolchain-Gang#355

Double escaping '$' for Makefile usage is fine, but
we should not use such a syntax while testing and trying
to run the oneliner output.

This change is 'unescaping' the '$$' to '$' so we can perform
some extra checks while using oneliner.

Otherwise as shown in this example a simple 'my $foo' test will fail.
@atoomic atoomic mentioned this issue Jul 21, 2020
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@atoomic
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atoomic commented Jul 21, 2020

My main concern is the way we perform the test t/oneliner.t and leads to use references.
I've no problem with the double escaping itself which is required for Makefile syntax.

Please view and consider #356

@atoomic
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atoomic commented Jul 21, 2020

a simple test like my $x in t/oneliner.t will show the issue, you can for example add a simple my when testing the oneliner function:
try_oneliner(q{my $PATH = 'foo'; print $PATH},[], q{foo}, 'dollar signs' );

which will lead to this error

t/oneliner.t ..
1..16
ok 1 - use ExtUtils::MM;
ok 2 - An object of class 'MM' isa 'ExtUtils::MakeMaker'
ok 3 - An object of class 'MM' isa 'ExtUtils::MM_Any'
ok 4 - quotes
Can't declare scalar dereference in "my" at -e line 1, near "$PATH ="
Execution of -e aborted due to compilation errors.
not ok 5 - dollar signs

#   Failed test 'dollar signs'
#   at t/oneliner.t line 41.
#          got: ''
#     expected: 'foo'
# oneliner:
# "/Users/nicolas/perl5/perlbrew/perls/perl-5.30.1/bin/perl"  -e 'my $$PATH = '\''foo'\''; print $$PATH' --

atoomic added a commit to atoomic/ExtUtils-MakeMaker that referenced this issue Jul 21, 2020
@atoomic
Test oneliner without double escaping dollar sign
db19381 
Fix Perl-Toolchain-Gang#355

Double escaping '$' for Makefile usage is fine, but
we should not use such a syntax while testing and trying
to run the oneliner output.

This change is 'unescaping' the '$$' to '$' so we can perform
some extra checks while using oneliner.

Otherwise as shown in this example a simple 'my $foo' test will fail.
atoomic added a commit to atoomic/ExtUtils-MakeMaker that referenced this issue Jul 22, 2020
@atoomic
Test oneliner without double escaping dollar sign
8eda217 
Fix Perl-Toolchain-Gang#355

Double escaping '$' for Makefile usage is fine, but
we should not use such a syntax while testing and trying
to run the oneliner output.

This change is 'unescaping' the '$$' to '$' so we can perform
some extra checks while using oneliner.

Otherwise as shown in this example a simple 'my $foo' test will fail.

Note we also have to unescape braces '{{' and '}}' used in dmake...
A better solution would be to produce a Makefile and run it directly.
atoomic added a commit to atoomic/ExtUtils-MakeMaker that referenced this issue Jul 22, 2020
@atoomic
Test oneliner using a temporary Makefile
c0319fa 
Fix Perl-Toolchain-Gang#355

Double escaping '$' for Makefile usage is fine, but
we should not use such a syntax while testing and trying
to run the oneliner output.

We could consider unescpaing '$$', '{{', '}}'... (for dmake)
but a cleaner solution is to test the oneliner in a Makefile
itself.
atoomic added a commit to atoomic/ExtUtils-MakeMaker that referenced this issue Jul 22, 2020
@atoomic
Test oneliner using a temporary Makefile
74d9a09 
Fix Perl-Toolchain-Gang#355

Double escaping '$' for Makefile usage is fine, but
we should not use such a syntax while testing and trying
to run the oneliner output.

We could consider unescpaing '$$', '{{', '}}'... (for dmake)
but a cleaner solution is to test the oneliner in a Makefile
itself.
atoomic added a commit to atoomic/ExtUtils-MakeMaker that referenced this issue Jul 22, 2020
@atoomic
Test oneliner using a temporary Makefile
ca37cb2 
Fix Perl-Toolchain-Gang#355

Double escaping '$' for Makefile usage is fine, but
we should not use such a syntax while testing and trying
to run the oneliner output.

We could consider unescpaing '$$', '{{', '}}'... (for dmake)
but a cleaner solution is to test the oneliner in a Makefile
itself.
atoomic added a commit to atoomic/ExtUtils-MakeMaker that referenced this issue Jul 22, 2020
@atoomic
Test oneliner using a temporary Makefile
9a150dc 
Fix Perl-Toolchain-Gang#355

Double escaping '$' for Makefile usage is fine, but
we should not use such a syntax while testing and trying
to run the oneliner output.

We could consider unescpaing '$$', '{{', '}}'... (for dmake)
but a cleaner solution is to test the oneliner in a Makefile
itself.
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Test oneliner without double escaping dollar sign atoomic/ExtUtils-MakeMaker
4 participants
@Leont @atoomic @Grinnz @mohawk2