Fix how analyzers are set in StringFieldMapper.

This was changed when adding the text field in an attempt to clean up
how analyzers are set. Unfortunately this change was not safe for the
string field given that it can also represent keywords.

core/src/main/java/org/elasticsearch/index/mapper/core/StringFieldMapper.java

@@ -154,9 +154,6 @@ public class StringFieldMapper extends FieldMapper implements AllFieldMapper.Inc
                     throw new IllegalArgumentException("Can't parse [index] value [" + index + "] for field [" + fieldName + "], expected [true], [false], [no], [not_analyzed] or [analyzed]");
                 }
             }
-            builder.fieldType().setIndexAnalyzer(parserContext.analysisService().defaultIndexAnalyzer());
-            builder.fieldType().setSearchAnalyzer(parserContext.analysisService().defaultSearchAnalyzer());
-            builder.fieldType().setSearchQuoteAnalyzer(parserContext.analysisService().defaultSearchQuoteAnalyzer());
             parseTextField(builder, fieldName, node, parserContext);
             for (Iterator<Map.Entry<String, Object>> iterator = node.entrySet().iterator(); iterator.hasNext();) {
                 Map.Entry<String, Object> entry = iterator.next();
@@ -174,6 +171,17 @@ public class StringFieldMapper extends FieldMapper implements AllFieldMapper.Inc
                         throw new MapperParsingException("positions_increment_gap less than 0 aren't allowed.");
                     }
                     builder.positionIncrementGap(newPositionIncrementGap);
+                    // we need to update to actual analyzers if they are not set in this case...
+                    // so we can inject the position increment gap...
+                    if (builder.fieldType().indexAnalyzer() == null) {
+                        builder.fieldType().setIndexAnalyzer(parserContext.analysisService().defaultIndexAnalyzer());
+                    }
+                    if (builder.fieldType().searchAnalyzer() == null) {
+                        builder.fieldType().setSearchAnalyzer(parserContext.analysisService().defaultSearchAnalyzer());
+                    }
+                    if (builder.fieldType().searchQuoteAnalyzer() == null) {
+                        builder.fieldType().setSearchQuoteAnalyzer(parserContext.analysisService().defaultSearchQuoteAnalyzer());
+                    }
                     iterator.remove();
                 } else if (propName.equals("ignore_above")) {
                     builder.ignoreAbove(XContentMapValues.nodeIntegerValue(propNode, -1));