SQL: Fix merging of incompatible multi-fields (#39560)

Fix bug in IndexResolver that caused conflicts in multi-field types to
be ignored up (causing the query to fail later on due to mapping
conflicts).
The issue was caused by the multi-field which forced the parent creation
before checking its validity across mappings

Fix #39547

(cherry picked from commit 4e4fe28)

Author: costin

x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/analysis/index/IndexResolver.java

@@ -324,7 +324,9 @@ static IndexResolution mergedMapping(String indexPattern, Map<String, Map<String
                 // if the name wasn't added before
                 final InvalidMappedField invalidF = invalidField;
                 final FieldCapabilities fieldCapab = fieldCap;
-                if (!flattedMapping.containsKey(name)) {
+                
+                EsField esField = flattedMapping.get(name);
+                if (esField == null || (invalidF != null && (esField instanceof InvalidMappedField) == false)) {
                     createField(name, fieldCaps, hierarchicalMapping, flattedMapping, s -> {
                         return invalidF != null ? invalidF : createField(s, fieldCapab.getType(), emptyMap(), fieldCapab.isAggregatable());
                     });

x-pack/plugin/sql/src/test/java/org/elasticsearch/xpack/sql/analysis/index/IndexResolverTests.java

@@ -132,6 +132,48 @@ public void testMetaFieldsAreIgnored() throws Exception {
         assertEquals(DataType.KEYWORD, esIndex.mapping().get("text").getDataType());
     }
 
+    public void testMergeIncompatibleCapabilitiesOfObjectFields() throws Exception {
+        Map<String, Map<String, FieldCapabilities>> fieldCaps = new HashMap<>();
+
+        int depth = randomInt(5);
+
+        List<String> level = new ArrayList<>();
+        String fieldName = randomAlphaOfLength(3);
+        level.add(fieldName);
+        for (int i = 0; i <= depth; i++) {
+            String l = randomAlphaOfLength(3);
+            level.add(l);
+            fieldName += "." + l;
+        }
+
+        // define a sub-field
+        addFieldCaps(fieldCaps, fieldName + ".keyword", "keyword", true, true);
+
+        Map<String, FieldCapabilities> multi = new HashMap<>();
+        multi.put("long", new FieldCapabilities(fieldName, "long", true, true, new String[] { "one-index" }, null, null));
+        multi.put("text", new FieldCapabilities(fieldName, "text", true, false, new String[] { "another-index" }, null, null));
+        fieldCaps.put(fieldName, multi);
+
+
+        String wildcard = "*";
+        IndexResolution resolution = IndexResolver.mergedMapping(wildcard, fieldCaps);
+
+        assertTrue(resolution.isValid());
+
+        EsIndex esIndex = resolution.get();
+        assertEquals(wildcard, esIndex.name());
+        EsField esField = null;
+        Map<String, EsField> props = esIndex.mapping();
+        for (String lvl : level) {
+            esField = props.get(lvl);
+            props = esField.getProperties();
+        }
+        assertEquals(InvalidMappedField.class, esField.getClass());
+        assertEquals("mapped as [2] incompatible types: [text] in [another-index], [long] in [one-index]",
+                ((InvalidMappedField) esField).errorMessage());
+    }
+
+
     public static IndexResolution merge(EsIndex... indices) {
         return IndexResolver.mergedMapping("*", fromMappings(indices));
     }