feat: do not check conformance of SVG content

EPUB 3.3 no longer requires that SVG content conforms to SVG content model requirements,
only that they are well-formed, that ID are uniques, and that they respect some additional
EPUB-specific requirements.

This commit:
  * introduces a new permissive RelaxNG schema for SVG, checking only the EPUB-specific
    requirements on the `title` and `foreignObject` content model
    see w3c/epub-specs#1323
  * removes checks on the value of the `requiredExtensions` attribute of `foreignObject`
    see w3c/epub-specs#1087
  * adapts the main XHTML to SVG schema driver to the new permissive SVG schema
  * adds various tests for EPUB-specific requirements

src/main/resources/com/adobe/epubcheck/schema/30/epub-svg-30.nvdl

@@ -4,7 +4,7 @@
 		<namespace ns="http://www.w3.org/2000/svg">
 			<validate schema="epub-svg-30.rnc" schemaType="application/relax-ng-compact-syntax"
 				useMode="allowForeignNS">
-				<context path="foreignObject" useMode="allowHTMLOnly"/>
+				<context path="foreignObject" useMode="attachAnyNS"/>
 			</validate>
 			<validate schema="epub-svg-30.sch" useMode="attachAnyNS"/>
 		</namespace>
@@ -29,23 +29,6 @@
 			<allow/>
 		</anyNamespace>
 	</mode>
-	<mode name="allowHTMLOnly">
-		<namespace ns="http://www.w3.org/1999/xhtml">
-			<attach/>
-		</namespace>
-		<namespace ns="http://www.idpf.org/2007/ops" match="attributes">
-			<attach/>
-		</namespace>
-		<namespace ns="http://www.w3.org/1999/xlink" match="attributes">
-			<attach/>
-		</namespace>
-		<namespace ns="http://www.w3.org/XML/1998/namespace" match="attributes">
-			<attach/>
-		</namespace>
-		<namespace ns="" match="attributes">
-			<attach/>
-		</namespace>
-	</mode>
 	<mode name="attachAnyNS">
 		<anyNamespace>
 			<attach/>

src/main/resources/com/adobe/epubcheck/schema/30/epub-svg-30.rnc

@@ -1 +1,17 @@
-include "./mod/epub-svg11.rnc"
+namespace svg = "http://www.w3.org/2000/svg"
+
+include "./mod/epub-xhtml.rnc" {
+  start = svg
+}
+include "./mod/epub-mathml3.rnc"
+include "./mod/epub-svg-inc.rnc"
+
+svg.title.content |= common.elem.phrasing
+
+svg.foreignObject.content |= 
+  ( body.elem
+  | common.inner.flow
+  | math 
+  )
+
+mtext.content |= common.elem.phrasing

src/main/resources/com/adobe/epubcheck/schema/30/epub-svg-30.sch

@@ -1,11 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <schema xmlns="http://purl.oclc.org/dsdl/schematron">    
 
-    <ns uri="http://www.w3.org/2000/svg" prefix="svg" />
-
-    <pattern></pattern>
     <include href="./mod/id-unique.sch"/>
-    <include href="./mod/epub-svg11-re.sch"/>
 
 </schema>
 

src/main/resources/com/adobe/epubcheck/schema/30/epub-xhtml-30.rnc

@@ -1,7 +1,17 @@
-## XHTML5
+namespace svg = "http://www.w3.org/2000/svg"
+
 include "./mod/epub-xhtml.rnc"
+include "./mod/epub-mathml3.rnc"
+include "./mod/epub-svg-inc.rnc" {
+  svg.attr.id = attribute id { datatype.html5.token }?
+}
+
+common.elem.phrasing |= svg
+common.elem.phrasing |= math
 
-## SVG and MathML
+svg.title.content |= common.elem.phrasing
 
-include "./mod/epub-xhtml-mathml3.rnc"
-include "./mod/epub-xhtml-svg11.rnc"
+svg.foreignObject.content |= 
+  ( common.inner.flow
+  | math 
+  )

src/main/resources/com/adobe/epubcheck/schema/30/epub-xhtml-30.sch

@@ -402,6 +402,4 @@
         </rule>
     </pattern>
 
-    <include href="./mod/epub-svg11-re.sch"/>
-
 </schema>

src/main/resources/com/adobe/epubcheck/schema/30/epub30-catalog.xml

@@ -52,13 +52,9 @@
            uri="mod/epub-ssml-attrs.rnc"/>
    <system systemId="epub-ssml-attrs.rnc" uri="mod/epub-ssml-attrs.rnc"/>
 
-   <system systemId="http://www.idpf.org/epub/30/schema/mod/epub-svg11.rnc"
-           uri="mod/epub-svg11.rnc"/>
-   <system systemId="epub-svg11.rnc" uri="mod/epub-svg11.rnc"/>
-
-   <system systemId="http://www.idpf.org/epub/30/schema/mod/epub-svg11-re.sch"
-           uri="mod/epub-svg11-re.sch"/>
-   <system systemId="epub-svg11-re.sch" uri="mod/epub-svg11-re.sch"/>
+   <system systemId="http://www.idpf.org/epub/30/schema/mod/epub-svg-inc.rnc"
+           uri="mod/epub-svg-inc.rnc"/>
+   <system systemId="epub-svg-inc.rnc" uri="mod/epub-svg-inc.rnc"/>
 
    <system systemId="http://www.idpf.org/epub/30/schema/mod/epub-switch.rnc"
            uri="mod/epub-switch.rnc"/>

src/main/resources/com/adobe/epubcheck/schema/30/mod/epub-svg-inc.rnc

@@ -0,0 +1,39 @@
+default namespace = "http://www.w3.org/2000/svg"
+
+# #####################################################################
+##  Anything-goes schema for svg                                      #
+# #####################################################################
+
+## SVG root
+svg = svg.elem
+svg.elem =
+  element svg { any.content & any.attr }
+
+## Special cases
+specific.elems =
+  ( svg.foreignObject
+  | svg.title
+  )
+specific.attrs = svg.attr.id
+
+### SVG ID datatype
+svg.attr.id = attribute id { xsd:ID }?
+
+### SVG foreignObject element restrictions
+svg.foreignObject = 
+  element foreignObject { any.attr & svg.foreignObject.content }
+svg.foreignObject.content = notAllowed
+
+### SVG title element restrictions
+svg.title =
+  element title { any.attr & svg.title.content }
+svg.title.content = text
+
+## Anything
+
+## Any attribute from any namespace, other than the special cases
+any.attr = attribute * -id { text }* & svg.attr.id
+## Any element from any namespace, other than the special cases
+any.elem = element * - (foreignObject|title) { any.content & any.attr }
+## Any content from any namespace
+any.content = text & any.elem* & specific.elems*

src/test/resources/epub3/content-document-svg.feature

@@ -19,7 +19,7 @@ Feature: EPUB 3 ▸ Content Documents ▸ SVG Document Checks
   ##  3.2 Content Conformance
 
   ###  ARIA attributes
- 
+
   Scenario: Verify ARIA attributes are allowed
     When checking document 'aria-attributes-valid.svg'
     Then no errors or warnings are reported
@@ -65,6 +65,12 @@ Feature: EPUB 3 ▸ Content Documents ▸ SVG Document Checks
     And the message contains 'Duplicate'
     And no other errors or warnings are reported
 
+  Scenario: Report invalid `id` attribute values 
+    When checking document 'id-invalid-error.svg'
+    Then error RSC-005 is reported
+    And the message contains '"id" is invalid'
+    And no other errors or warnings are reported
+
   ### Style Attribute
 
   Scenario: Verify `style` element without explicit `type` (issue 688)
@@ -84,20 +90,51 @@ Feature: EPUB 3 ▸ Content Documents ▸ SVG Document Checks
     When checking document 'foreignObject-valid.svg'
     Then no errors or warnings are reported
 
-  Scenario: Report `foreignObject` with a `requiredExtensions` attribute with a non-OPS namespace 
-    When checking document 'foreignObject-requiredExtensions-ns-error.svg'
+  Scenario: Verify that the `requiredExtensions` attribute can have any value
+    Note: 'requiredExensions' was required to be set to 'http://www.idpf.org/2007/ops' in EPUB 3.2 and earlier versions  
+    When checking document 'foreignObject-requiredExtensions-valid.svg'
+    Then no errors or warnings are reported
+
+  Scenario: Report `foreignObject` with non-HTML child content 
+    When checking document 'foreignObject-not-html-error.svg'
     Then error RSC-005 is reported
-    And the message contains 'Invalid value (expecting: "http://www.idpf.org/2007/ops")'
+    And the message contains 'element "foo" not allowed here'
     And no other errors or warnings are reported
-  
-  Scenario: Report `foreignObject` with non-HTML child content 
-    When checking document 'foreignObject-non-html-content-error.svg'
+
+  Scenario: Report `foreignObject` with non-flow content
+    When checking document 'foreignObject-not-flow-content-error.svg'
     Then error RSC-005 is reported
-    And the message contains 'elements from namespace "https://example.org" are not allowed'
+    And the message contains 'element "title" not allowed here'
     And no other errors or warnings are reported
-  
+
   Scenario: Report `foreignObject` with multiple HTML `body` elements
     When checking document 'foreignObject-multiple-body-error.svg'
     Then error RSC-005 is reported
-    And the message contains 'element "h:body" not allowed here'
+    And the message contains 'element "body" not allowed here'
+    And no other errors or warnings are reported
+
+  Scenario: Report HTML validation errors within `foreignObject` content
+    When checking document 'foreignObject-html-invalid-error.svg'
+    Then error RSC-005 is reported
+    And the message contains 'attribute "href" not allowed here'
+    And no other errors or warnings are reported
+
+  Scenario: Verify `title` can contain text
+    When checking document 'title-text-valid.svg'
+    Then no errors or warnings are reported
+
+  Scenario: Verify `title` can contain HTML phrasing content
+    When checking document 'title-phrasing-content-valid.svg'
+    Then no errors or warnings are reported
+
+  Scenario: Report `title` with non-phrasing content
+    When checking document 'title-not-phrasing-content-error.svg'
+    Then error RSC-005 is reported
+    And the message contains 'element "h1" not allowed here'
+    And no other errors or warnings are reported
+
+  Scenario: Report HTML validation errors within `title` content
+    When checking document 'title-html-invalid-error.svg'
+    Then error RSC-005 is reported
+    And the message contains 'attribute "href" not allowed here'
     And no other errors or warnings are reported

src/test/resources/epub3/content-document-xhtml.feature

@@ -710,26 +710,25 @@ Feature: EPUB 3 ▸ Content Documents ▸ XHTML Document Checks
     When checking document 'svg-valid.xhtml'
     Then no errors or warnings are reported
 
+  Scenario: Verify conforming SVG markup does not create false-positives
+    When checking document 'svg-regression-valid.xhtml'
+    Then no errors or warnings are reported
+  Scenario: Verify the SVG IDs can be any valid HTML ID
+    When checking document 'svg-id-valid.xhtml'
+    Then no errors or warnings are reported
+
   Scenario: Verify that `epub:type` attribute can be used on SVG
     When checking document 'svg-with-epubtype-valid.xhtml'
     Then no errors or warnings are reported
 
-  Scenario: Report SVG with invalid content model
-    When checking document 'svg-error.xhtml'
-    Then error RSC-005 is reported 
-    And the message contains 'The svg element must not appear inside title elements'
-    And no other errors or warnings are reported
-
-  Scenario: Report SVG with incorrect `requiredExtensions` attribute value
-    When checking document 'svg-requiredExtensions-error.xhtml'
-    Then error RSC-005 is reported
-    And the message contains 'Invalid value (expecting: "http://www.idpf.org/2007/ops")'
+  Scenario: Verify that SVG validation erors are reported as USAGE
+    Given the reporting level set to usage 
+    When checking document 'svg-invalid-usage.xhtml'
+    #Then usage SVG-000 is reported 
+    #And the message contains 'element "foo" not allowed here'
     And no other errors or warnings are reported
 
-  Scenario: Verify `xlink:href` allowed on SVG elements
-    When checking document 'svg-links-valid.xhtml'
-    Then no errors or warnings are reported
-
+  #TODO review if this warning is relevant
   Scenario: Report an SVG link without a recommended title
     When checking document 'svg-links-no-title-warning.xhtml'
     Then warning ACC-011 is reported
@@ -739,19 +738,48 @@ Feature: EPUB 3 ▸ Content Documents ▸ XHTML Document Checks
     When checking document 'svg-foreignObject-valid.xhtml'
     Then no errors or warnings are reported
 
-  Scenario: Report `foreignObject` with disallowed body element
+  Scenario: Verify that the `requiredExtensions` attribute can have any value
+    When checking document 'svg-foreignObject-requiredExtensions-valid.xhtml'
+    And no other errors or warnings are reported
+
+  Scenario: Report `foreignObject` with a body element
     When checking document 'svg-foreignObject-with-body-error.xhtml'
     Then error RSC-005 is reported
     And the message contains 'element "body" not allowed here'
     And no other errors or warnings are reported
+
+  Scenario: Report HTML validation errors within `foreignObject` content
+    When checking document 'svg-foreignObject-html-invalid-error.xhtml'
+    Then error RSC-005 is reported
+    And the message contains 'attribute "href" not allowed here'
+    And no other errors or warnings are reported
 
   Scenario: Report `foreignObject` without flow content
-    When checking document 'svg-foreignObject-no-flow-error.xhtml'
+    When checking document 'svg-foreignObject-not-flow-content-error.xhtml'
     Then error RSC-005 is reported
     And the message contains 'element "title" not allowed here'
     And no other errors or warnings are reported
 
-#  Still not allowed by epubcheck - https://github.com/w3c/epubcheck/issues/173
-#  Scenario: Verify RDF elements can be embedded in SVG
-#    When checking document 'svg-rdf-valid.xhtml'
-#    Then no errors or warnings are reported
+  Scenario: Verify `title` can contain text
+    When checking document 'svg-title-text-valid.xhtml'
+    Then no errors or warnings are reported
+
+  Scenario: Verify `title` can contain HTML phrasing content
+    When checking document 'svg-title-phrasing-content-valid.xhtml'
+    Then no errors or warnings are reported
+
+  Scenario: Report `title` with non-phrasing content
+    When checking document 'svg-title-not-phrasing-content-error.xhtml'
+    Then error RSC-005 is reported
+    And the message contains 'element "h1" not allowed here'
+    And no other errors or warnings are reported
+
+  Scenario: Report HTML validation errors within `title` content
+    When checking document 'svg-title-html-invalid-error.xhtml'
+    Then error RSC-005 is reported
+    And the message contains 'attribute "href" not allowed here'
+    And no other errors or warnings are reported
+
+  Scenario: Verify RDF elements can be embedded in SVG
+    When checking document 'svg-rdf-valid.xhtml'
+    Then no errors or warnings are reported