stow_contents: fix bugs and corner cases with type mismatch conflicts

If the target directory as a file named X and a package has a
directory named X, or vice-versa, then it is impossible for Stow
to stow that entry X from the package, even if --adopt is supplied.

However we were previously only handling the former case, and not the
latter, and the test for the former was actually broken.  So fix
stow_contents() to handle both cases correctly, fix the broken test,
and add a new test for the latter case.

lib/Stow.pm.in

@@ -603,6 +603,15 @@ sub stow_node {
     elsif ($self->is_a_node($target_subpath)) {
         debug(4, 1, "Evaluate existing node: $target_subpath");
         if ($self->is_a_dir($target_subpath)) {
+            if (! -d $pkg_path_from_cwd) {
+                # FIXME: why wasn't this ever needed before?
+                $self->conflict(
+                    'stow',
+                    $package,
+                    "cannot stow non-directory $pkg_path_from_cwd over existing directory target $target_subpath"
+                );
+            }
+            else {
                 $self->stow_contents(
                     $self->{stow_path},
                     $package,
@@ -610,16 +619,29 @@ sub stow_node {
                     $target_subpath,
                 );
             }
+        }
         else {
+            # If we're here, $target_subpath is not a current or
+            # planned directory.
+
             if ($self->{adopt}) {
+                if (-d $pkg_path_from_cwd) {
+                    $self->conflict(
+                        'stow',
+                        $package,
+                        "cannot stow directory $pkg_path_from_cwd over existing non-directory target $target_subpath"
+                    );
+                }
+                else {
                     $self->do_mv($target_subpath, $pkg_path_from_cwd);
                     $self->do_link($link_dest, $target_subpath);
                 }
+            }
             else {
                 $self->conflict(
                     'stow',
                     $package,
-                    "existing target is neither a link nor a directory: $target_subpath"
+                    "cannot stow $pkg_path_from_cwd over existing target $target_subpath since neither a link nor a directory and --adopt not specified"
                 );
             }
         }

t/stow.t

@@ -22,7 +22,7 @@
 use strict;
 use warnings;
 
-use Test::More tests => 21;
+use Test::More tests => 22;
 use Test::Output;
 use English qw(-no_match_vars);
 
@@ -103,7 +103,7 @@ subtest("Package dir 'bin4' conflicts with existing non-dir so can't unfold", su
     is($stow->get_conflict_count, 1);
     like(
         $conflicts{stow}{pkg4}[0],
-        qr/existing target is neither a link nor a directory/
+        qr!cannot stow ../stow/pkg4/bin4 over existing target bin4 since neither a link nor a directory and --adopt not specified!
         => 'link to new dir bin4 conflicts with existing non-directory'
     );
 });
@@ -111,8 +111,7 @@ subtest("Package dir 'bin4' conflicts with existing non-dir so can't unfold", su
 subtest("Package dir 'bin4a' conflicts with existing non-dir " .
         "so can't unfold even with --adopt", sub {
     plan tests => 2;
-    #my $stow = new_Stow(adopt => 1);
+    my $stow = new_Stow(adopt => 1);
-    my $stow = new_Stow();
 
     make_file('bin4a'); # this is a file but named like a directory
     make_path('../stow/pkg4a/bin4a');
@@ -121,8 +120,9 @@ subtest("Package dir 'bin4a' conflicts with existing non-dir " .
     $stow->plan_stow('pkg4a');
     %conflicts = $stow->get_conflicts();
     is($stow->get_conflict_count, 1);
-    like($conflicts{stow}{pkg4a}[0],
+    like(
-        qr/existing target is neither a link nor a directory/
+        $conflicts{stow}{pkg4a}[0],
+        qr!cannot stow directory ../stow/pkg4a/bin4a over existing non-directory target bin4a!
         => 'link to new dir bin4a conflicts with existing non-directory'
     );
 });
@@ -146,14 +146,42 @@ subtest("Package files 'file4b' and 'bin4b' conflict with existing files", sub {
     %conflicts = $stow->get_conflicts();
     is($stow->get_conflict_count, 2 => 'conflict per file');
     for my $i (0, 1) {
+        my $target = $i ? 'file4b' : 'bin4b/file4b';
         like(
             $conflicts{stow}{pkg4b}[$i],
-            qr/existing target is neither a link nor a directory/
+            qr,cannot stow ../stow/pkg4b/$target over existing target $target since neither a link nor a directory and --adopt not specified,
             => 'link to file4b conflicts with existing non-directory'
         );
     }
 });
 
+subtest("Package files 'file4d' conflicts with existing directories", sub {
+    plan tests => 3;
+    my $stow = new_Stow();
+
+    # Populate target
+    make_path('file4d');  # this is a directory but named like a file to create the conflict
+    make_path('bin4d/file4d'); # same here
+
+    # Populate stow package
+    make_path('../stow/pkg4d');
+    make_file('../stow/pkg4d/file4d',       'file4d - version originally in stow package');
+    make_path('../stow/pkg4d/bin4d');
+    make_file('../stow/pkg4d/bin4d/file4d', 'bin4d/file4d - version originally in stow package');
+
+    $stow->plan_stow('pkg4d');
+    %conflicts = $stow->get_conflicts();
+    is($stow->get_conflict_count, 2 => 'conflict per file');
+    for my $i (0, 1) {
+        my $target = $i ? 'file4d' : 'bin4d/file4d';
+        like(
+            $conflicts{stow}{pkg4d}[$i],
+            qr!cannot stow non-directory ../stow/pkg4d/$target over existing directory target $target!
+            => 'link to file4d conflicts with existing non-directory'
+        );
+    }
+});
+
 subtest("Package files 'file4c' and 'bin4c' can adopt existing versions", sub {
     plan tests => 8;
     my $stow = new_Stow(adopt => 1);