Add :ignore_index_errors option to Database#create_table and :ignore_…

…errors option to Database#add_index

The schema_dumper extension is going to be using these options to
make it more likely that the migrations it generates will be
loadable.  Since indexes generally have no effect on behavior
(except for unique indexes), the inability to load one shouldn't
be a reason to cancel the migration.

I'm not happy with this way of doing things, but I can't really
think of a better idea that will allow dumping of PostgreSQL tables
with indexes on text columns and attempting to restore them on
MySQL.

CHANGELOG

@@ -1,5 +1,7 @@
 === HEAD
 
+* Add :ignore_index_errors option to Database#create_table and :ignore_errors option to Database#add_index (jeremyevans)
+
 * Make graphing a complex dataset work correctly (jeremyevans)
 
 * Fix MySQL command out of sync errors, disconnect from database if they occur (jeremyevans)

lib/sequel/database/schema_methods.rb

@@ -16,9 +16,18 @@ def add_column(table, *args)
     #   DB.add_index :posts, :title
     #   DB.add_index :posts, [:author, :title], :unique => true
     #
+    #
+    # Options:
+    # * :ignore_errors - Ignore any DatabaseErrors that are raised
+    #
     # See alter_table.
-    def add_index(table, *args)
-      alter_table(table) {add_index(*args)}
+    def add_index(table, columns, options={})
+      e = options[:ignore_errors]
+      begin
+        alter_table(table){add_index(columns, options)}
+      rescue DatabaseError
+        raise unless e
+      end
     end
 
     # Alters the given table with the specified block. Example:
@@ -55,6 +64,7 @@ def alter_table(name, generator=nil, &block)
     #
     # Options:
     # * :temp - Create the table as a temporary table.
+    # * :ignore_index_errors - Ignore any errors when creating indexes.
     #
     # See Schema::Generator.
     def create_table(name, options={}, &block)
@@ -180,7 +190,14 @@ def create_table_from_generator(name, generator, options)
 
     # Execute the create index statements using the generator.
     def create_table_indexes_from_generator(name, generator, options)
-      index_sql_list(name, generator.indexes).each{|sql| execute_ddl(sql)}
+      e = options[:ignore_index_errors]
+      index_sql_list(name, generator.indexes).each do |sql|
+        begin
+          execute_ddl(sql)
+        rescue DatabaseError
+          raise unless e
+        end
+      end
     end
   end
 end

spec/core/schema_spec.rb

@@ -333,6 +333,15 @@
     }.should raise_error(Sequel::Error)
   end
 
+  specify "should ignore errors if the database raises an error on an index creation statement and the :ignore_index_errors option is used" do
+    @db.meta_def(:execute_ddl){|*a| raise Sequel::DatabaseError if /blah/.match(a.first); super(*a)}
+    lambda{@db.create_table(:cats){Integer :id; index :blah; index :id}}.should raise_error(Sequel::DatabaseError)
+    @db.sqls.should == ['CREATE TABLE cats (id integer)']
+    @db.sqls.clear
+    lambda{@db.create_table(:cats, :ignore_index_errors=>true){Integer :id; index :blah; index :id}}.should_not raise_error(Sequel::DatabaseError)
+    @db.sqls.should == ['CREATE TABLE cats (id integer)', 'CREATE INDEX cats_id_index ON cats (id)']
+  end
+
   specify "should accept multiple index definitions" do
     @db.create_table(:cats) do
       integer :id
@@ -642,6 +651,13 @@
     @db.sqls.should == ["CREATE INDEX cats_name_index ON cats (name)"]
   end
 
+  specify "should ignore errors if the database raises an error on an add_index call and the :ignore_errors option is used" do
+    @db.meta_def(:execute_ddl){|*a| raise Sequel::DatabaseError}
+    lambda{@db.add_index(:cats, :id)}.should raise_error(Sequel::DatabaseError)
+    lambda{@db.add_index(:cats, :id, :ignore_errors=>true)}.should_not raise_error(Sequel::DatabaseError)
+    @db.sqls.should == nil
+  end
+
   specify "should support add_primary_key" do
     @db.alter_table(:cats) do
       add_primary_key :id