Merge pull request #1555 from Catchwa/regexp_replace-ignore-global-flag

In the REGEXP_REPLACE function, when in PostgreSQL compatibility mode, accept the 'g' flag.

h2/src/docsrc/html/features.html

@@ -950,7 +950,12 @@ or the SQL statement <code>SET MODE PostgreSQL</code>.
 </li><li>The system columns <code>CTID</code> and
     <code>OID</code> are supported.
 </li><li>LOG(x) is base 10 in this mode.
-</li><li>REGEXP_REPLACE() uses \ for back-references.
+</li><li>REGEXP_REPLACE():
+    <ul>
+    <li>Uses \ for back-references</li>
+    <li>Will not throw an exception when the <code>flagsString</code> parameter contains a 'g'</li>
+    <li>In the absence of the 'g' flag in the <code>flagsString</code> parameter, only the first-matched substring will be replaced</li>
+    </ul>
 </li><li>Fixed-width strings are padded with spaces.
 </li><li>MONEY data type is treated like NUMERIC(19, 2) data type.
 </li><li>Datetime value functions return the same value within a transaction.

h2/src/main/org/h2/expression/Function.java

@@ -1370,12 +1370,20 @@ public class Function extends Expression implements FunctionCall {
             }
             String regexpMode = v3 == null || v3.getString() == null ? "" :
                     v3.getString();
-            int flags = makeRegexpFlags(regexpMode);
+            boolean isInPostgreSqlMode = Mode.ModeEnum.PostgreSQL.equals(database.getMode().getEnum());
+            int flags = makeRegexpFlags(regexpMode, isInPostgreSqlMode);
             try {
+                if(isInPostgreSqlMode && !regexpMode.contains("g")) {
+                  result = ValueString.get(
+                    Pattern.compile(regexp, flags).matcher(v0.getString())
+                      .replaceFirst(replacement),
+                    database.getMode().treatEmptyStringsAsNull);
+                } else {
                   result = ValueString.get(
                     Pattern.compile(regexp, flags).matcher(v0.getString())
                       .replaceAll(replacement),
                     database.getMode().treatEmptyStringsAsNull);
+                }
             } catch (StringIndexOutOfBoundsException e) {
                 throw DbException.get(
                         ErrorCode.LIKE_ESCAPE_ERROR_1, e, replacement);
@@ -1650,7 +1658,7 @@ public class Function extends Expression implements FunctionCall {
             String regexp = v1.getString();
             String regexpMode = v2 == null || v2.getString() == null ? "" :
                     v2.getString();
-            int flags = makeRegexpFlags(regexpMode);
+            int flags = makeRegexpFlags(regexpMode, false);
             try {
                 result = ValueBoolean.get(Pattern.compile(regexp, flags)
                         .matcher(v0.getString()).find());
@@ -2032,7 +2040,7 @@ public class Function extends Expression implements FunctionCall {
         return md;
     }
 
-    private static int makeRegexpFlags(String stringFlags) {
+    private static int makeRegexpFlags(String stringFlags, boolean ignoreGlobalFlag) {
         int flags = Pattern.UNICODE_CASE;
         if (stringFlags != null) {
             for (int i = 0; i < stringFlags.length(); ++i) {
@@ -2049,6 +2057,11 @@ public class Function extends Expression implements FunctionCall {
                     case 'm':
                         flags |= Pattern.MULTILINE;
                         break;
+                    case 'g':
+                        if (ignoreGlobalFlag) {
+                            break;
+                        }
+                    //$FALL-THROUGH$
                     default:
                         throw DbException.get(ErrorCode.INVALID_VALUE_2, stringFlags);
                 }

h2/src/test/org/h2/test/scripts/functions/string/regex-replace.sql

@@ -35,3 +35,21 @@ select regexp_replace('first last', '(\w+) (\w+)', '\2 \1');
 
 select regexp_replace('first last', '(\w+) (\w+)', '$2 $1');
 >> last first
+
+select regexp_replace('AbcDef', '[^a-z]', '', 'g');
+> exception INVALID_VALUE_2
+
+select regexp_replace('First and Second', '[A-Z]', '');
+>> irst and econd
+
+set mode PostgreSQL;
+> ok
+
+select regexp_replace('AbcDef', '[^a-z]', '', 'g');
+>> bcef
+
+select regexp_replace('AbcDef123', '[a-z]', '!', 'gi');
+>> !!!!!!123
+
+select regexp_replace('First Only', '[A-Z]', '');
+>> irst Only