XML::Twig 使用“map_xmlns”时 twig_roots 可能存在错误寻找顶级标签的子代时的选项

Question

我在测试Perl模块XML :: Twig时遇到了以下奇怪的行为，其中包括参数twig_handlers and twig_roots以及'map_xmlns'选项（perl版本：5.30.2，xml :: twig :: twig vig version：3.52）。

背景：

几年来，我一直在使用Perl模块XML :: Twig。特别是我使用了twig_roots和twig_handlers参数来从大型XML文件中提取数据，将整个文件加载到内存不切实际。

在过去的几个月中，我在使用上述twig_roots和twig_handlers参数时发现了“ map_xmlns”选项。当要分析的相同类型的XML文件包含不同的标签前缀时，此选项非常有用。

我发现的奇怪行为在以下代码中概述了。

use strict;
use warnings;
use XML::Twig;
use Data::Dumper;

my %map_xmlns_hash;
my $prefix_val='x';
$map_xmlns_hash{'http://schemas.testdata/info'}=$prefix_val;
my $tag_to_look_forA='/' . $prefix_val . ':items';
my $tag_to_look_forB='/' . $prefix_val . ':items/' . $prefix_val . ':item';
        
my $dataA = '
<items>
    <item>
        <data1>data1A</data1>
        <data2>data2A</data2>
    </item>
    <item>
        <data1>data1B</data1>
        <data2>data2B</data2>
    </item>
</items>';
        
my $dataB = '
<x:items xmlns:x="http://schemas.testdata/info">
    <x:item>
        <x:data1>data1C</x:data1>
        <x:data2>data2C</x:data2>
    </x:item>
    <x:item>
        <x:data1>data1D</x:data1>
        <x:data2>data2D</x:data2>
    </x:item>
</x:items>';
#
# 1a.) twig_handlers test when no xmlns mapping used on root (top level) tag '/items'
#
my  @Array1h;
my $t1h = XML::Twig->new(
    pretty_print => 'indented',
    twig_handlers => {  
        'items' => sub {Get_children_data(@_,\@Array1h)}})->parse($dataA);
print Dumper \@Array1h;
#
# 1b.) twig_roots test when no xmlns mapping used on root (top level) tag '/items'
#
my  @Array1r;
my $t1r = XML::Twig->new(
    pretty_print => 'indented',
    twig_roots => {
        'items' => sub {Get_children_data(@_,\@Array1r)}})->parse($dataA);
print Dumper \@Array1r;
#
# 2a.) twig_handlers test with xmlns mapping used on root (top level) tag '/items'
#
my  @Array2h;
my $t2h = XML::Twig->new(
    map_xmlns => {
        %map_xmlns_hash
    },
    keep_original_prefix =>1,
    pretty_print => 'indented',
    twig_handlers => {
        $tag_to_look_forA => sub {Get_children_data(@_,\@Array2h)}})->parse($dataB);
print Dumper \@Array2h;
#
# 2b.) twig_roots test with xmlns mapping used on root (top level) tag '/items'
#
my  @Array2r;
my $t2r = XML::Twig->new(
    map_xmlns => {
        %map_xmlns_hash
    },
    keep_original_prefix =>1,
    pretty_print => 'indented',
    twig_roots => {
        $tag_to_look_forA => sub {Get_children_data(@_,\@Array2r);}})->parse($dataB);
print Dumper \@Array2r;
#
# 3a.) twig_handlers test with xmlns mapping used on tag '/items/item'
#
my  @Array3h;
my $t3h = XML::Twig->new(
    map_xmlns => {
        %map_xmlns_hash
    },
    keep_original_prefix =>1,
    pretty_print => 'indented',
    twig_handlers => {
        $tag_to_look_forB => sub {Get_children_data(@_,\@Array3h)}})->parse($dataB);
print Dumper \@Array3h;
#
# 3b.) twig_roots test with xmlns mapping used on tag '/items/item'
#
my  @Array3r;
my $t3r = XML::Twig->new(
    map_xmlns => {
        %map_xmlns_hash
    },
    keep_original_prefix =>1,
    pretty_print => 'indented',
    twig_roots => {
        $tag_to_look_forB => sub {Get_children_data(@_,\@Array3r);}})->parse($dataB);
print Dumper \@Array3r;
#
#
#
sub Get_children_data{
    my( $t, $elt,$Array1)= @_;
    my @children_list=$elt->children();
    for my $iChild (0 .. scalar @children_list-1){
        push @$Array1,$children_list[$iChild]->name();
    }
    $t->purge;
}

上述代码的结果是：

$VAR1 = [
      'item',
      'item'
    ];
$VAR1 = [
      'item',
      'item'
    ];
$VAR1 = [
      'x:item',
      'x:item'
    ];
$VAR1 = [];
$VAR1 = [
      'x:data1',
      'x:data2',
      'x:data1',
      'x:data2'
    ];
$VAR1 = [
      'x:data1',
      'x:data2',
      'x:data1',
      'x:data2'
    ];

这表明2B。）错误返回没有子信息数据！

用'twig_handlers'[2a。）替换“ twig_roots” [2b。）]生成所需的结果。

最后两个示例[3a。）和3b。）]证明“ twig_roots”和“ twig_handlers'参数都可以按预期使用，而“``map_xmlns'''''''tag forge nove nove nove nove noc of the tag noc of the not as dog as noc cot（top Level） 。

我无法弄清楚问题是什么。在寻找顶级标签的子标签时，使用“ map_xmlns”选项时，是否有一个错误？