Overwrite if the md5sum in a file is wrong but the content has not changed

Changes

@@ -2,6 +2,9 @@ Revision history for Perl extension DBIx::Class::Schema::Loader
 
         - Introspect view definitions for PostgreSQL, MySQL, Oracle,
           Firebird, and InterBase.
+        - When a file's md5sum was wrong but no other content in the file had
+          changed, it would not be rewritten even when overwrite_modifications
+          was true. Fixed by Dave Rolsky. GH #8.
 
 0.07045  2016-01-22
         - Regenerate tarball without author-mode test dependencies

lib/DBIx/Class/Schema/Loader/Base.pm

@@ -2252,9 +2252,16 @@ sub _parse_generated_file {
 
             $gen .= $pre_md5;
             $real_md5 = Digest::MD5::md5_base64(encode 'UTF-8', $gen);
-            croak "Checksum mismatch in '$fn', the auto-generated part of the file has been modified outside of this loader.  Aborting.\nIf you want to overwrite these modifications, set the 'overwrite_modifications' loader option.\n"
-                if !$self->overwrite_modifications && $real_md5 ne $mark_md5;
-
+            if ($real_md5 ne $mark_md5) {
+                if ($self->overwrite_modifications) {
+                    # Setting this to something that is not a valid MD5 forces
+                    # the file to be rewritten.
+                    $real_md5 = 'not an MD5';
+                }
+                else {
+                    croak "Checksum mismatch in '$fn', the auto-generated part of the file has been modified outside of this loader.  Aborting.\nIf you want to overwrite these modifications, set the 'overwrite_modifications' loader option.\n";
+                }
+            }
             last;
         }
         else {

t/40overwrite_modifications.t

@@ -22,16 +22,7 @@ dump_schema();
 ok( -f $foopm, 'looks like it dumped' );
 
 # now modify one of the files
-{
-    open my $in, '<', $foopm or die "$! reading $foopm";
-    my ($tfh,$temp) = tempfile( UNLINK => 1);
-    while(<$in>) {
-        s/"bars"/"somethingelse"/;
-        print $tfh $_;
-    }
-    close $tfh;
-    copy( $temp, $foopm );
-}
+rewrite_foopm($foopm, qr{"bars"}, q{"somethingelse"});
 
 # and dump again without overwrites
 throws_ok {
@@ -43,8 +34,37 @@ lives_ok {
     dump_schema( overwrite_modifications => 1 );
 } 'does not throw when dumping with overwrite_modifications';
 
+# Replace the md5 with a bad MD5 in Foo.pm
+my $foopm_content = slurp_file($foopm);
+my ($md5) = $foopm_content =~/md5sum:(.+)$/m;
+# This cannot be just any arbitrary value, it has to actually look like an MD5
+# value or DBICSL doesn't even see it as an MD5 at all (which makes sense).
+my $bad_md5 = reverse $md5;
+rewrite_foopm($foopm, qr{md5sum:.+$}, "md5sum:$bad_md5");
 
-unlike slurp_file $foopm, qr/"somethingelse"/, "Modifications actually overwritten";
+# and dump again without overwrites
+throws_ok {
+    dump_schema();
+} qr/mismatch/, 'throws error dumping without overwrite_modifications';
+
+$foopm_content = slurp_file($foopm);
+like(
+    $foopm_content,
+    qr/\Q$bad_md5/,
+    'bad MD5 is not rewritten when overwrite_modifications is false'
+);
+
+# and then dump with overwrite
+lives_ok {
+    dump_schema( overwrite_modifications => 1 );
+} 'does not throw when dumping with overwrite_modifications';
+
+$foopm_content = slurp_file($foopm);
+unlike(
+    $foopm_content,
+    qr/\Q$bad_md5/,
+    'bad MD5 is rewritten when overwrite_modifications is true'
+);
 
 sub dump_schema {
 
@@ -60,7 +80,23 @@ sub dump_schema {
             { dump_directory => $tempdir, @$args },
             [ $make_dbictest_db::dsn ],
         );
-    } [qr/^Dumping manual schema/, qr/^Schema dump completed/ ];
+    } [qr/^Dumping manual schema/, qr/^Schema dump completed/ ],
+    'schema was dumped with expected warnings';
+}
+
+sub rewrite_foopm {
+    my $foopm  = shift;
+    my $match  = shift;
+    my $replace = shift;
+
+    open my $in, '<', $foopm or die "$! reading $foopm";
+    my ($tfh, $temp) = tempfile( UNLINK => 1);
+    while(<$in>) {
+        s/$match/$replace/;
+        print $tfh $_;
+    }
+    close $tfh;
+    copy( $temp, $foopm );
 }
 
 done_testing();