Make join_paths correctly handle absolute paths

Previously join_paths() was incorrectly handling absolute paths, for
example join_paths('a/b', '/c/d') would return 'a/b/c/d' rather than
'/c/d'.  This was a problem when following a symlink in
find_stowed_path(), because if the symlink was not owned by Stow and
pointed to an absolute path, find_stowed_path() might accidentally
deem the link owned by Stow, if c/d was a valid path relative to the
current directory.
This commit is contained in:
Adam Spiers 2024-03-29 22:52:12 +00:00
parent ff4d87efaf
commit 4d711fc4ac
2 changed files with 61 additions and 97 deletions

View file

@ -32,6 +32,7 @@ Supporting utility routines for L<Stow>.
use strict; use strict;
use warnings; use warnings;
use File::Spec;
use POSIX qw(getcwd); use POSIX qw(getcwd);
use base qw(Exporter); use base qw(Exporter);
@ -147,29 +148,43 @@ sub debug {
# Parameters: path1, path2, ... => paths # Parameters: path1, path2, ... => paths
# Returns : concatenation of given paths # Returns : concatenation of given paths
# Throws : n/a # Throws : n/a
# Comments : factors out redundant path elements: # Comments : Factors out some redundant path elements:
# : '//' => '/' and 'a/b/../c' => 'a/c' # : '//' => '/', and 'a/b/../c' => 'a/c'. This is needed even
# : though b could be a symlink to elsewhere as noted in the
# : perldoc for File::Spec->canonpath(), because the way
# : join_paths() is used relies on this.
#============================================================================ #============================================================================
sub join_paths { sub join_paths {
my @paths = @_; my @paths = @_;
# weed out empty components and concatenate debug(5, 5, "| Joining: @paths");
my $result = join '/', grep {! /\A\z/} @paths; my $result = '';
for my $part (@paths) {
next if ! length $part; # probably shouldn't happen?
$part = File::Spec->canonpath($part);
# factor out back references and remove redundant /'s) if (substr($part, 0, 1) eq '/') {
my @result = (); $result = $part; # absolute path, so ignore all previous parts
PART:
for my $part (split m{/+}, $result) {
next PART if $part eq '.';
if (@result && $part eq '..' && $result[-1] ne '..') {
pop @result;
} }
else { else {
push @result, $part; $result .= '/' if length $result && $result ne '/';
$result .= $part;
} }
debug(7, 6, "| Join now: $result");
} }
debug(6, 5, "| Joined: $result");
return join '/', @result; # Need this to remove any initial ./
$result = File::Spec->canonpath($result);
# remove foo/..
1 while $result =~ s,(^|/)(?!\.\.)[^/]+/\.\.(/|$),$1,;
debug(6, 5, "| After .. removal: $result");
$result = File::Spec->canonpath($result);
debug(5, 5, "| Final join: $result");
return $result;
} }
#===== METHOD =============================================================== #===== METHOD ===============================================================

View file

@ -22,91 +22,40 @@
use strict; use strict;
use warnings; use warnings;
use Stow::Util qw(join_paths); use Stow::Util qw(join_paths set_debug_level);
use Test::More tests => 14; #set_debug_level(4);
is( use Test::More tests => 22;
join_paths('a/b/c', 'd/e/f'),
'a/b/c/d/e/f' my @TESTS = (
=> 'simple' [['a/b/c', 'd/e/f'], 'a/b/c/d/e/f' => 'simple'],
[['a/b/c', '/d/e/f'], '/d/e/f' => 'relative then absolute'],
[['/a/b/c', 'd/e/f'], '/a/b/c/d/e/f' => 'absolute then relative'],
[['/a/b/c', '/d/e/f'], '/d/e/f' => 'two absolutes'],
[['/a/b/c/', '/d/e/f/'], '/d/e/f' => 'two absolutes with trailing /'],
[['///a/b///c//', '/d///////e/f'], '/d/e/f' => "multiple /'s, absolute"],
[['///a/b///c//', 'd///////e/f'], '/a/b/c/d/e/f' => "multiple /'s, relative"],
[['', 'a/b/c'], 'a/b/c' => 'first empty'],
[['a/b/c', ''], 'a/b/c' => 'second empty'],
[['/', 'a/b/c'], '/a/b/c' => 'first is /'],
[['a/b/c', '/'], '/' => 'second is /'],
[['../a1/b1/../c1/', 'a2/../b2/e2'], '../a1/c1/b2/e2' => 'relative with ../'],
[['../a1/b1/../c1/', '/a2/../b2/e2'], '/b2/e2' => 'absolute with ../'],
[['../a1/../../c1', 'a2/../../'], '../..' => 'lots of ../'],
[['./', '../a2'], '../a2' => 'drop any "./"'],
[['./a1', '../../a2'], '../a2' => 'drop any "./foo"'],
[['a/b/c', '.'], 'a/b/c' => '. on RHS'],
[['a/b/c', '.', 'd/e'], 'a/b/c/d/e' => '. in middle'],
[['0', 'a/b'], '0/a/b' => '0 at start'],
[['/0', 'a/b'], '/0/a/b' => '/0 at start'],
[['a/b/c', '0', 'd/e'], 'a/b/c/0/d/e' => '0 in middle'],
[['a/b', '0'], 'a/b/0' => '0 at end'],
); );
is( for my $test (@TESTS) {
join_paths('/a/b/c', '/d/e/f'), my ($inputs, $expected, $scenario) = @$test;
'/a/b/c/d/e/f' my $got = join_paths(@$inputs);
=> 'leading /' my $descr = "$scenario: in=[" . join(', ', map "'$_'", @$inputs) . "] exp=[$expected] got=[$got]";
); is($got, $expected, $descr);
}
is(
join_paths('/a/b/c/', '/d/e/f/'),
'/a/b/c/d/e/f'
=> 'trailing /'
);
is(
join_paths('///a/b///c//', '/d///////e/f'),
'/a/b/c/d/e/f'
=> 'mltiple /\'s'
);
is(
join_paths('', 'a/b/c'),
'a/b/c'
=> 'first empty'
);
is(
join_paths('a/b/c', ''),
'a/b/c'
=> 'second empty'
);
is(
join_paths('/', 'a/b/c'),
'/a/b/c'
=> 'first is /'
);
is(
join_paths('a/b/c', '/'),
'a/b/c'
=> 'second is /'
);
is(
join_paths('///a/b///c//', '/d///////e/f'),
'/a/b/c/d/e/f'
=> 'multiple /\'s'
);
is(
join_paths('../a1/b1/../c1/', '/a2/../b2/e2'),
'../a1/c1/b2/e2'
=> 'simple deref ".."'
);
is(
join_paths('../a1/b1/../c1/d1/e1', '../a2/../b2/c2/d2/../e2'),
'../a1/c1/d1/b2/c2/e2'
=> 'complex deref ".."'
);
is(
join_paths('../a1/../../c1', 'a2/../../'),
'../..'
=> 'too many ".."'
);
is(
join_paths('./a1', '../../a2'),
'../a2'
=> 'drop any "./"'
);
is(
join_paths('a/b/c', '.'),
'a/b/c'
=> '. on RHS'
);