Don't delete existing file when trying to update a read-only archive, PR: 28419

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@276327 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -114,7 +114,10 @@ Fixed bugs:
   behaved identically.
 
 * <xslt> now sets the context classloader if you've specified a nested
-  <classpath>.  Bugzilla report 24802.
+  <classpath>.  Bugzilla Report 24802.
+
+* <zip> and friends would delete the original file when trying to update
+  a read-only archive.  Bugzilla Report 28419.
 
 Other changes:
 --------------

src/main/org/apache/tools/ant/taskdefs/Zip.java

@@ -338,6 +338,14 @@ public class Zip extends MatchingTask {
                                      + archiveType + " file to create!");
         }
 
+        if (zipFile.exists() && !zipFile.isFile()) {
+            throw new BuildException(zipFile + " is not a file.");
+        }
+
+        if (zipFile.exists() && !zipFile.canWrite()) {
+            throw new BuildException(zipFile + " is read-only.");
+        }
+
         // Renamed version of original file, if it exists
         File renamedFile = null;
         // Whether or not an actual update is required -