Resolve RT#64208, solving the issue of duplicate paths ONCE AND FOR ALL.

If asked to add a path that is already the most recent path activated,
local::lib won't try to doanything. If asked to add a path that's
already been activated further down the stack, it will remove it from
its current position and re-add, thus making it the new "most recent
path" without duplication. In other cases, everything is the same.

This adds yet another variable to pass down through three layers of
method calls. Something must be done about those.

diff --git a/lib/local/lib.pm b/lib/local/lib.pm
index 7881af9..098c31e 100644 (file)
--- a/lib/local/lib.pm
+++ b/lib/local/lib.pm
@@ -18,6 +18,9 @@ our @KNOWN_FLAGS = qw(--self-contained --deactivate --deactivate-all);
 sub DEACTIVATE_ONE () { 1 }
 sub DEACTIVATE_ALL () { 2 }
 
+sub INTERPOLATE_ENV () { 1 }
+sub LITERAL_ENV     () { 0 }
+
 sub import {
   my ($class, @args) = @_;
 
@@ -200,9 +203,28 @@ is($c->resolve_relative_path('bar'),'FOObar');
 
 sub setup_local_lib_for {
   my ($class, $path, $deactivating) = @_;
-  $path = $class->ensure_dir_structure_for($path) unless $deactivating;
+
+  my $interpolate = LITERAL_ENV;
+  my @active_lls = $class->active_paths;
+
+  if (! $deactivating) {
+    if (@active_lls && $active_lls[-1] eq $path) {
+      exit 0 if $0 eq '-';
+      return; # Asked to add what's already at the top of the stack
+    } elsif (grep { $_ eq $path} @active_lls) {
+      # Asked to add a dir that's lower in the stack -- so we remove it from
+      # where it is, and then add it back at the top.
+      $class->setup_env_hash_for($path, DEACTIVATE_ONE);
+      # Which means we can no longer output "PERL5LIB=...:$PERL5LIB" stuff
+      # anymore because we're taking something *out*.
+      $interpolate = INTERPOLATE_ENV;
+    }
+  }
+
+  $path = $class->ensure_dir_structure_for($path);
+
   if ($0 eq '-') {
-    $class->print_environment_vars_for($path, $deactivating);
+    $class->print_environment_vars_for($path, $deactivating, $interpolate);
     exit 0;
   } else {
     $class->setup_env_hash_for($path, $deactivating);
@@ -238,9 +260,6 @@ sub ensure_dir_structure_for {
   return $path;
 }
 
-sub INTERPOLATE_ENV () { 1 }
-sub LITERAL_ENV     () { 0 }
-
 sub guess_shelltype {
   my $shellbin = 'sh';
   if(defined $ENV{'SHELL'}) {
@@ -277,13 +296,13 @@ sub guess_shelltype {
 }
 
 sub print_environment_vars_for {
-  my ($class, $path, $deactivating) = @_;
-  print $class->environment_vars_string_for($path, $deactivating);
+  my ($class, $path, $deactivating, $interpolate) = @_;
+  print $class->environment_vars_string_for($path, $deactivating, $interpolate);
 }
 
 sub environment_vars_string_for {
-  my ($class, $path, $deactivating) = @_;
-  my @envs = $class->build_environment_vars_for($path, $deactivating, LITERAL_ENV);
+  my ($class, $path, $deactivating, $interpolate) = @_;
+  my @envs = $class->build_environment_vars_for($path, $deactivating, $interpolate);
   my $out = '';
 
   # rather basic csh detection, goes on the assumption that something won't