X-Git-Url: http://git.vpit.fr/?p=perl%2Fmodules%2Findirect.git;a=blobdiff_plain;f=lib%2Findirect.pm;h=76a3ee0a47ee78ec03dcb963259608557cd47cc7;hp=7028f93a755cfd82248a7fd220bf0acefa70c7ea;hb=eb25d798995d30e0d78d38dd746c28961ec3d71d;hpb=554466eac93eb0abec78e190fe175b03eec782f2 diff --git a/lib/indirect.pm b/lib/indirect.pm index 7028f93..76a3ee0 100644 --- a/lib/indirect.pm +++ b/lib/indirect.pm @@ -1,54 +1,64 @@ package indirect; -use 5.008; +use 5.008001; use strict; use warnings; =head1 NAME -indirect - Lexically warn about using the indirect object syntax. +indirect - Lexically warn about using the indirect method call syntax. =head1 VERSION -Version 0.14 +Version 0.26 =cut our $VERSION; BEGIN { - $VERSION = '0.14'; + $VERSION = '0.26'; } =head1 SYNOPSIS - # In a script - no indirect; +In a script : + + no indirect; # lexically enables the pragma my $x = new Apple 1, 2, 3; # warns { - use indirect; - my $y = new Pear; # ok + use indirect; # lexically disables the pragma + my $y = new Pear; # legit, does not warn { - no indirect hook => sub { die "You really wanted $_[0]\->$_[1]" }; - my $z = new Pineapple 'fresh'; # croaks 'You really wanted Pineapple->new' + # lexically specify an hook called for each indirect construct + no indirect hook => sub { + die "You really wanted $_[0]\->$_[1] at $_[2]:$_[3]" + }; + my $z = new Pineapple 'fresh'; # croaks 'You really wanted...' } } - no indirect ':fatal'; + try { ... }; # warns if try() hasn't been declared in this package + + no indirect 'fatal'; # or ':fatal', 'FATAL', ':Fatal' ... if (defied $foo) { ... } # croaks, note the typo - # From the command-line - perl -M-indirect -e 'my $x = new Banana;' # warns +Global uses : + + # Globally enable the pragma from the command-line + perl -M-indirect=global -e 'my $x = new Banana;' # warns - # Or each time perl is ran - export PERL5OPT="-M-indirect" - perl -e 'my $y = new Coconut;' # warns + # Globally enforce the pragma each time perl is executed + export PERL5OPT="-M-indirect=global,fatal" + perl -e 'my $y = new Coconut;' # croaks =head1 DESCRIPTION -When enabled (or disabled as some may prefer to say, since you actually turn it on by calling C), this pragma warns about indirect object syntax constructs that may have slipped into your code. -This syntax is now considered harmful, since its parsing has many quirks and its use is error prone (when C isn't defined, C actually compiles to C<< $x->swoosh >>). +When enabled, this pragma warns about indirect method calls that are present in your code. -It currently does not warn when the object is enclosed between braces (like C) or for core functions (C or C). +The indirect syntax is now considered harmful, since its parsing has many quirks and its use is error prone : when the subroutine C has not been declared in the current package, C actually compiles to C<< $x->foo >>, and C<< foo { key => 1 } >> to C<< 'key'->foo(1) >>. +In L, Matt S. Trout gives an example of an undesirable indirect method call on a block that can cause a particularly bewildering error. + +This pragma currently does not warn for core functions (C, C, C or C). This may change in the future, or may be added as optional features that would be enabled by passing options to C. This module is B a source filter. @@ -56,13 +66,26 @@ This module is B a source filter. =cut BEGIN { - require XSLoader; - XSLoader::load(__PACKAGE__, $VERSION); + if ($ENV{PERL_INDIRECT_PM_DISABLE}) { + *_tag = sub ($) { 1 }; + *I_THREADSAFE = sub () { 1 }; + *I_FORKSAFE = sub () { 1 }; + } else { + require XSLoader; + XSLoader::load(__PACKAGE__, $VERSION); + } } =head1 METHODS -=head2 C<< unimport [ hook => $hook | ':fatal' ] >> +=head2 C + + no indirect; + no indirect 'fatal'; + no indirect hook => sub { my ($obj, $name, $file, $line) = @_; ... }; + no indirect 'global'; + no indirect 'global, 'fatal'; + no indirect 'global', hook => sub { ... }; Magically called when C is encountered. Turns the module on. @@ -72,76 +95,172 @@ The policy to apply depends on what is first found in C<@opts> : =item * -If it's the string C<':fatal'>, the compilation will croak on the first indirect syntax met. +If it is a string that matches C, the compilation will croak when the first indirect method call is found. + +This option is mutually exclusive with the C<'hook'> option. + +=item * + +If the key/value pair C<< hook => $hook >> comes first, C<$hook> will be called for each error with a string representation of the object as C<$_[0]>, the method name as C<$_[1]>, the current file as C<$_[2]> and the line number as C<$_[3]>. +If and only if the object is actually a block, C<$_[0]> is assured to start by C<'{'>. + +This option is mutually exclusive with the C<'fatal'> option. =item * -If the key/value pair C<< hook => $hook >> comes first, C<$hook> will be called for each error with the object name as C<$_[0]>, the method name as C<$_[1]>, the current file as C<$_[2]> and the line number as C<$_[3]>. +If none of C and C are specified, a warning will be emitted for each indirect method call. =item * -Otherwise, a warning will be emitted for each indirect construct. +If C<@opts> contains a string that matches C, the pragma will be globally enabled for B code compiled after the current C statement, except for code that is in the lexical scope of C. +This option may come indifferently before or after the C or C options, in the case they are also passed to L. + +The global policy applied is the one resulting of the C or C options, thus defaults to a warning when none of those are specified : + + no indirect 'global'; # warn for any indirect call + no indirect qw; # die on any indirect call + no indirect 'global', hook => \&hook # custom global action + +Note that if another policy is installed by a C statement further in the code, it will overrule the global policy : + + no indirect 'global'; # warn globally + { + no indirect 'fatal'; # throw exceptions for this lexical scope + ... + require Some::Module; # the global policy will apply for the + # compilation phase of this module + } =back =cut -my $msg = sub { - "Indirect call of method \"$_[1]\" on object \"$_[0]\" at $_[2] line $_[3].\n" -}; +sub _no_hook_and_fatal { + require Carp; + Carp::croak("The 'fatal' and 'hook' options are mutually exclusive"); +} sub unimport { shift; - my $hook; + my ($global, $fatal, $hook); + while (@_) { my $arg = shift; if ($arg eq 'hook') { + _no_hook_and_fatal() if $fatal; $hook = shift; - } elsif ($arg eq ':fatal') { - $hook = sub { die $msg->(@_) }; + } elsif ($arg =~ /^:?fatal$/i) { + _no_hook_and_fatal() if defined $hook; + $fatal = 1; + } elsif ($arg =~ /^:?global$/i) { + $global = 1; } - last if $hook; } - $hook = sub { warn $msg->(@_) } unless defined $hook; + + unless (defined $hook) { + $hook = $fatal ? sub { die msg(@_) } : sub { warn msg(@_) }; + } $^H |= 0x00020000; - $^H{+(__PACKAGE__)} = _tag($hook); + if ($global) { + delete $^H{+(__PACKAGE__)}; + _global($hook); + } else { + $^H{+(__PACKAGE__)} = _tag($hook); + } - (); + return; } =head2 C + use indirect; + Magically called at each C. Turns the module off. +As explained in L's description, an C statement will lexically override a global policy previously installed by C (if there's one). + =cut sub import { - $^H{+(__PACKAGE__)} = undef; - (); + $^H |= 0x00020000; + $^H{+(__PACKAGE__)} = _tag(undef); + + return; } +=head1 FUNCTIONS + +=head2 C + + my $msg = msg($object, $method, $file, $line); + +Returns the default error message that C generates when an indirect method call is reported. + +=cut + +sub msg { + my $obj = $_[0]; + + join ' ', "Indirect call of method \"$_[1]\" on", + ($obj =~ /^\s*\{/ ? "a block" : "object \"$obj\""), + "at $_[2] line $_[3].\n"; +}; + =head1 CONSTANTS =head2 C -True iff the module could have been built when thread-safety features. +True iff the module could have been built with thread-safety features enabled. + +=head2 C + +True iff this module could have been built with fork-safety features enabled. +This will always be true except on Windows where it's false for perl 5.10.0 and below . + +=head1 DIAGNOSTICS + +=head2 C + +The default warning/exception message thrown when an indirect method call on an object is found. + +=head2 C + +The default warning/exception message thrown when an indirect method call on a block is found. + +=head1 ENVIRONMENT + +=head2 C + +If this environment variable is set to true when the pragma is used for the first time, the XS code won't be loaded and, although the C<'indirect'> lexical hint will be set to true in the scope of use, the pragma itself won't do anything. +In this case, the pragma will always be considered to be thread-safe, and as such L will be true. +This is useful for disabling C in production environments. + +Note that clearing this variable after C was loaded has no effect. +If you want to re-enable the pragma later, you also need to reload it by deleting the C<'indirect.pm'> entry from C<%INC>. =head1 CAVEATS -The implementation was tweaked to work around several limitations of vanilla C pragmas : it's thread safe, and doesn't suffer from a C bug that causes all pragmas to propagate into Cd scopes. +The implementation was tweaked to work around several limitations of vanilla C pragmas : it's thread safe, and does not suffer from a C bug that causes all pragmas to propagate into Cd scopes. -C (no semicolon) at the end of a file won't be seen as an indirect object syntax, although it will as soon as there is another token before the end (as in C or C). +Before C 5.12, C (no semicolon) at the end of a file is not seen as an indirect method call, although it is as soon as there is another token before the end (as in C or C). +If you use C 5.12 or greater, those constructs are correctly reported. With 5.8 perls, the pragma does not propagate into C. This is due to a shortcoming in the way perl handles the hints hash, which is addressed in perl 5.10. +The search for indirect method calls happens before constant folding. +Hence C will be caught. + =head1 DEPENDENCIES -L 5.8. +L 5.8.1. + +A C compiler. +This module may happen to build with a C++ compiler as well, but don't rely on it, as no guarantee is made in this regard. -L (standard since perl 5.006). +L (standard since perl 5), L (since perl 5.006). =head1 AUTHOR @@ -166,9 +285,11 @@ Tests code coverage report is available at L