Allow contains to apply to objects as well as arrays

Author: jdesrosiers

jsonschema-core.xml

@@ -2380,12 +2380,20 @@
                             even if none of its elements is valid against the given schema.
                         </t>
                         <t>
-                            This keyword produces an annotation value which is an array of
-                            the indexes to which this keyword validates successfully when applying
-                            its subschema, in ascending order. The value MAY be a boolean "true" if
-                            the subschema validates successfully when applied to every index of the
-                            instance. The annotation MUST be present if the instance array to which
-                            this keyword's schema applies is empty.
+                            An object instance is valid against "contains" if at least one of
+                            its properties is valid against the given schema,
+                            except when "minContains" is present and has a value of 0, in which
+                            case an object instance MUST be considered valid against the "contains" keyword,
+                            even if none of its property values is valid against the given schema.
+                        </t>
+                        <t>
+                            This keyword produces an annotation value which is an array of the
+                            indexes or property names to which this keyword validates successfully
+                            when applying its subschema, in ascending order. The value MAY be a
+                            boolean "true" if the subschema validates successfully when applied to
+                            every index or property value of the instance. The annotation MUST be
+                            present if the instance array or object to which this keyword's schema
+                            applies is empty.
                         </t>
                         <t>
                             This annotation affects the behavior of "unevaluatedItems" in the

jsonschema-validation.xml

@@ -414,13 +414,13 @@
                         then this keyword has no effect.
                     </t>
                     <t>
-                        An instance array is valid against "maxContains" in two ways, depending on
-                        the form of the annotation result of an adjacent
+                        An instance array or object is valid against "maxContains" in two ways,
+                        depending on the form of the annotation result of an adjacent
                         <xref target="json-schema">"contains"</xref> keyword. The first way is if
                         the annotation result is an array and the length of that array is less than
                         or equal to the "maxContains" value. The second way is if the annotation
-                        result is a boolean "true" and the instance array length is less than or
-                        equal to the "maxContains" value.
+                        result is a boolean "true" and the instance length is less than or equal to
+                        the "maxContains" value.
                     </t>
                 </section>
 
@@ -433,13 +433,13 @@
                         then this keyword has no effect.
                     </t>
                     <t>
-                        An instance array is valid against "minContains" in two ways, depending on
-                        the form of the annotation result of an adjacent
+                        An instance array or object is valid against "minContains" in two ways,
+                        depending on the form of the annotation result of an adjacent
                         <xref target="json-schema">"contains"</xref> keyword. The first way is if
                         the annotation result is an array and the length of that array is greater
                         than or equal to the "minContains" value. The second way is if the
-                        annotation result is a boolean "true" and the instance array length is
-                        greater than or equal to the "minContains" value.
+                        annotation result is a boolean "true" and the instance length is greater
+                        than or equal to the "minContains" value.
                     </t>
                     <t>
                         A value of 0 is allowed, but is only useful for setting a range