Bug 64450: Allow to parse a file where the relationship-id is an empty string

Also improve exception reporting by including more information and not
"hiding" the actual exception-cause in a log-statement.

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1885056 13f79535-47bb-0310-9956-ffa450edef68

src/ooxml/java/org/apache/poi/openxml4j/opc/PackageRelationshipCollection.java

@@ -194,7 +194,8 @@ public final class PackageRelationshipCollection implements
      */
     public void addRelationship(PackageRelationship relPart) {
         if (relPart == null || relPart.getId() == null || relPart.getId().isEmpty()) {
-            throw new IllegalArgumentException("invalid relationship part/id");
+            throw new IllegalArgumentException("invalid relationship part/id: " +
+                    (relPart == null ? "<null>" : relPart.getId()) + " for relationship: " + relPart);
         }
         relationshipsByID.put(relPart.getId(), relPart);
         relationshipsByType.put(relPart.getRelationshipType(), relPart);
@@ -216,7 +217,7 @@ public final class PackageRelationshipCollection implements
      */
     public PackageRelationship addRelationship(URI targetUri,
             TargetMode targetMode, String relationshipType, String id) {
-      if (id == null) {
+      if (id == null || id.length() == 0) {
          // Generate a unique ID is id parameter is null.
          if (nextRelationshipId == -1) {
             nextRelationshipId = size() + 1;
@@ -354,8 +355,7 @@ public final class PackageRelationshipCollection implements
                 addRelationship(target, targetMode, type, id);
             }
         } catch (Exception e) {
-            logger.log(POILogger.ERROR, e);
-            throw new InvalidFormatException(e.getMessage());
+            throw new InvalidFormatException("Failed to parse relationships", e);
         }
     }
 

src/ooxml/testcases/org/apache/poi/xssf/usermodel/TestXSSFBugs.java

@@ -3660,4 +3660,11 @@ public final class TestXSSFBugs extends BaseTestBugzillaIssues {
             assertEquals(1, sheet.getDataValidations().size());
         }
     }
+
+    @Test
+    public void test64450() throws IOException {
+        try (Workbook wb = XSSFTestDataSamples.openSampleWorkbook("64450.xlsx")) {
+            assertNotNull(wb);
+        }
+    }
 }