From: Ben Tilly Date: Sat, 1 Dec 2001 07:01:09 +0000 (-0500) Subject: Enabling strict on Carp/Heavy, + internal documentation X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=a3775ca3239946dafd17edff355bf2a7e4e86b61;p=p5sagit%2Fp5-mst-13.2.git Enabling strict on Carp/Heavy, + internal documentation Date: Sat, 1 Dec 2001 07:01:09 -0500 Message-ID: <3C0D2E39@operamail.com> Subject: More verbose POD for Carp From: "Benjamin J. Tilly" Date: Sat, 1 Dec 2001 08:04:16 -0500 Message-ID: <3C285C2B@operamail.com> p4raw-id: //depot/perl@13416 --- diff --git a/lib/Carp.pm b/lib/Carp.pm index cd2cfdb..84508b2 100644 --- a/lib/Carp.pm +++ b/lib/Carp.pm @@ -1,6 +1,6 @@ package Carp; -our $VERSION = '1.00'; +our $VERSION = '1.01'; =head1 NAME @@ -13,6 +13,10 @@ croak - die of errors (from perspective of caller) confess - die of errors with stack backtrace +shortmess - return the message that carp and croak produce + +longmess - return the message that cluck and confess produce + =head1 SYNOPSIS use Carp; @@ -27,16 +31,54 @@ confess - die of errors with stack backtrace =head1 DESCRIPTION The Carp routines are useful in your own modules because -they act like die() or warn(), but report where the error -was in the code they were called from. Thus if you have a -routine Foo() that has a carp() in it, then the carp() -will report the error as occurring where Foo() was called, -not where carp() was called. +they act like die() or warn(), but with a message which is more +likely to be useful to a user of your module. In the case of +cluck, confess, and longmess that context is a summary of every +call in the call-stack. For a shorter message you can use carp, +croak or shortmess which report the error as being from where +your module was called. There is no guarantee that that is where +the error was, but it is a good educated guess. + +Here is a more complete description of how shortmess works. What +it does is search the call-stack for a function call stack where +it hasn't been told that there shouldn't be an error. If every +call is marked safe, it then gives up and gives a full stack +backtrace instead. In other words it presumes that the first likely +looking potential suspect is guilty. Its rules for telling whether +a call shouldn't generate errors work as follows: + +=over 4 + +=item 1. + +Any call from a package to itself is safe. + +=item 2. + +Packages claim that there won't be errors on calls to or from +packages explicitly marked as safe by inclusion in @CARP_NOT, or +(if that array is empty) @ISA. The ability to override what +@ISA says is new in 5.8. + +=item 3. -The routine shortmess() can be used to generate the string that -carp/croak would have produced. The routine longmess() can be -used to generate the backtrace that cluck/confess would have -produced. +The trust in item 2 is transitive. If A trusts B, and B +trusts C, then A trusts C. So if you do not override @ISA +with @CARP_NOT, then this trust relationship is identical to, +"inherits from". + +=item 4. + +Any call from an internal Perl module is safe. (Nothing keeps +user modules from marking themselves as internal to Perl, but +this practice is discouraged.) + +=item 5. + +Any call to Carp is safe. (This rule is what keeps it from +reporting the error where you call carp/croak/shortmess.) + +=back =head2 Forcing a Stack Trace @@ -67,19 +109,25 @@ call die() or warn(), as appropriate. # _almost_ complete understanding of the package. Corrections and # comments are welcome. -# The $CarpLevel variable can be set to "strip off" extra caller levels for -# those times when Carp calls are buried inside other functions. The +# The members of %Internal are packages that are internal to perl. +# Carp will not report errors from within these packages if it +# can. The members of %CarpInternal are internal to Perl's warning +# system. Carp will not report errors from within these packages +# either, and will not report calls *to* these packages for carp and +# croak. They replace $CarpLevel, which is deprecated. The # $Max(EvalLen|(Arg(Len|Nums)) variables are used to specify how the eval # text and function arguments should be formatted when printed. +$CarpInternal{Carp}++; $CarpLevel = 0; # How many extra package levels to skip on carp. + # How many calls to skip on confess. + # Reconciling these notions is hard, use + # %Internal and %CarpInternal instead. $MaxEvalLen = 0; # How much eval '...text...' to show. 0 = all. $MaxArgLen = 64; # How much of each argument to print. 0 = all. $MaxArgNums = 8; # How many arguments to print. 0 = all. $Verbose = 0; # If true then make shortmess call longmess instead -$CarpInternal{Carp}++; - require Exporter; @ISA = ('Exporter'); @EXPORT = qw(confess croak carp); diff --git a/lib/Carp/Heavy.pm b/lib/Carp/Heavy.pm index 06d57b5..5228b9b 100644 --- a/lib/Carp/Heavy.pm +++ b/lib/Carp/Heavy.pm @@ -28,7 +28,7 @@ sub caller_info { my $sub_name = Carp::get_subname(\%call_info); if ($call_info{has_args}) { - my @args = map {Carp::format_arg($_)} @args; + my @args = map {Carp::format_arg($_)} @DB::args; if ($MaxArgNums and @args > $MaxArgNums) { # More than we want to show? $#args = $MaxArgNums; push @args, '...'; @@ -236,7 +236,10 @@ sub trusts { # Takes a package and gives a list of those trusted directly sub trusts_directly { my $class = shift; - return @{"$class\::ISA"}; + no strict 'refs'; + return @{"$class\::CARP_NOT"} + ? @{"$class\::CARP_NOT"} + : @{"$class\::ISA"}; } 1;