Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=47371

markt-asf · markt-asf · commit d9b950522d1b · 2011-05-05T13:39:09.000Z
Correctly coerce the empty string to zero when used as an operand in EL arithmetic. Patch provided by gbt. git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1099789 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/java/org/apache/el/lang/ELArithmetic.java b/java/org/apache/el/lang/ELArithmetic.java
@@ -394,13 +394,12 @@ protected final Number coerce(final Object obj) {
         if (isNumber(obj)) {
             return coerce((Number) obj);
         }
-        if (obj instanceof String) {
-            return coerce((String) obj);
-        }
         if (obj == null || "".equals(obj)) {
             return coerce(ZERO);
         }
-
+        if (obj instanceof String) {
+            return coerce((String) obj);
+        }
         if (obj instanceof Character) {
             return coerce(Short.valueOf((short) ((Character) obj).charValue()));
         }
diff --git a/test/org/apache/el/lang/TestELArithmetic.java b/test/org/apache/el/lang/TestELArithmetic.java
@@ -49,4 +49,9 @@ public void testMod() throws Exception {
         assertEquals("1.1",
                 String.valueOf(ELArithmetic.mod(a, b)));
     }
+
+    public void testBug47371() throws Exception {
+        assertEquals("1",
+                String.valueOf(ELArithmetic.add("", Integer.valueOf(1))));
+    }
 }
diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml
@@ -164,6 +164,10 @@
   </subsection>
   <subsection name="Jasper">
     <changelog>
+      <fix>
+        <bug><47371/bug>: Correctly coerce the empty string to zero when used as
+        an operand in EL arithmetic. Patch provided by gbt. (markt)
+      </fix>
       <add>
         Label JSP/tag file line and column numbers when reporting errors since
         it may not be immediately obvious what the numbers represent. (markt)

Original file line number	Diff line number	Diff line change
`@@ -394,13 +394,12 @@ protected final Number coerce(final Object obj) {`
`394`	`394`	`if (isNumber(obj)) {`
`395`	`395`	`return coerce((Number) obj);`
`396`	`396`	`}`
`397`		`- if (obj instanceof String) {`
`398`		`- return coerce((String) obj);`
`399`		`- }`
`400`	`397`	`if (obj == null \|\| "".equals(obj)) {`
`401`	`398`	`return coerce(ZERO);`
`402`	`399`	`}`
`403`		`-`
	`400`	`+ if (obj instanceof String) {`
	`401`	`+ return coerce((String) obj);`
	`402`	`+ }`
`404`	`403`	`if (obj instanceof Character) {`
`405`	`404`	`return coerce(Short.valueOf((short) ((Character) obj).charValue()));`
`406`	`405`	`}`
Original file line number	Diff line number	Diff line change
`@@ -49,4 +49,9 @@ public void testMod() throws Exception {`
`49`	`49`	`assertEquals("1.1",`
`50`	`50`	`String.valueOf(ELArithmetic.mod(a, b)));`
`51`	`51`	`}`
	`52`	`+`
	`53`	`+ public void testBug47371() throws Exception {`
	`54`	`+ assertEquals("1",`
	`55`	`+ String.valueOf(ELArithmetic.add("", Integer.valueOf(1))));`
	`56`	`+ }`
`52`	`57`	`}`