bugzilla ID 38199, symlink fails on second call

bugzilla ID 43426, <symlink> cant create a symlink over a file

solution is the same: opt for ln -sf after trying to do it internally. We could perhaps drop all ant deletion operations, for a much simpler operation.

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@577281 13f79535-47bb-0310-9956-ffa450edef68

WHATSNEW

@@ -41,6 +41,13 @@ Changes that could break older environments:
 Fixed bugs:
 -----------
 
+ * <symlink> task couldn't overwrite existing symlinks that pointed to nonexistent files
+   Bugzilla report 38199
+
+ * <symlink> task couldn't overwrite files that were in the way of the symlink.
+   Bugzilla report 43426
+
+
 Other changes:
 --------------
 

src/main/org/apache/tools/ant/taskdefs/optional/unix/Symlink.java

@@ -404,7 +404,7 @@ public class Symlink extends DispatchTask {
      *                                   fail.
      */
     public static void deleteSymlink(File linkfil)
-        throws IOException, FileNotFoundException {
+        throws IOException{
         if (!linkfil.exists()) {
             throw new FileNotFoundException("No such symlink: " + linkfil);
         }
@@ -466,6 +466,7 @@ public class Symlink extends DispatchTask {
      *
      * @param msg    The message to log, or include in the
      *                  <code>BuildException</code>.
+     * @throws BuildException with the message if failonerror=true
      */
     private void handleError(String msg) {
         if (failonerror) {
@@ -481,20 +482,24 @@ public class Symlink extends DispatchTask {
      *
      * @param res   The path of the resource we are linking to.
      * @param lnk       The name of the link we wish to make.
+     * @throws BuildException when things go wrong
      */
     private void doLink(String res, String lnk) throws BuildException {
         File linkfil = new File(lnk);
-        if (overwrite && linkfil.exists()) {
-            try {
-                deleteSymlink(linkfil);
-            } catch (FileNotFoundException fnfe) {
-                handleError("Symlink disappeared before it was deleted: " + lnk);
-            } catch (IOException ioe) {
-                handleError("Unable to overwrite preexisting link: " + lnk);
+        String options = "-s";
+        if (overwrite) {
+            options += "f";
+            if (linkfil.exists()) {
+                try {
+                    deleteSymlink(linkfil);
+                } catch (FileNotFoundException fnfe) {
+                    log("Symlink disappeared before it was deleted: " + lnk);
+                } catch (IOException ioe) {
+                    log("Unable to overwrite preexisting link or file: " + lnk,ioe, Project.MSG_INFO);
+                }
             }
         }
-        String[] cmd = new String[] {"ln", "-s", res, lnk};
-        log(Commandline.toString(cmd));
+        String[] cmd = new String[] {"ln", options, res, lnk};
         Execute.runCommand(this, cmd);
     }
 

src/tests/antunit/taskdefs/optional/unix/symlink-test.xml

@@ -0,0 +1,55 @@
+<?xml version="1.0" encoding="utf-8"?>
+<project name="symlink-test"
+    default="antunit" xmlns:au="antlib:org.apache.ant.antunit">
+  <import file="../../../antunit-base.xml"/>
+
+  <property name="build.dir" location="build" />
+
+  <target name="setUp">
+    <condition property="isUnix">
+      <os family="unix" />
+    </condition>
+  </target>
+
+  <target name="os">
+
+    <mkdir dir="${build.dir}" />
+    <condition property="unix">
+      <os family="unix" />
+    </condition>
+    <property name="file_ref"
+      location="${build.dir}/file"/>
+    <property name="hanging_ref"
+        location="${build.dir}/hanging_ref"/>
+  </target>
+
+  <target name="init" depends="os" if="unix">
+    <touch file="${file_ref}" />
+  </target>
+
+  <target name="tearDown">
+    <delete dir="${build.dir}" />
+  </target>
+
+  <target name="testCreateDouble" depends="init" if="unix">
+    <symlink overwrite="true" link="${build.dir}/link"
+        resource="${file_ref}"/>
+    <symlink overwrite="true" link="${build.dir}/link"
+        resource="${file_ref}"/>
+  </target>
+
+
+  <target name="testCreateDoubleHanging" depends="init" if="unix">
+    <symlink overwrite="true" link="${build.dir}/link2"
+        resource="${hanging_ref}"/>
+    <symlink overwrite="true" link="${build.dir}/link2"
+        resource="${hanging_ref}"/>
+  </target>
+
+  <target name="testCreateOverFile" depends="init" if="unix">
+    <touch file="${build.dir}/link3" />
+    <symlink overwrite="true" link="${build.dir}/link3"
+        resource="${file_ref}"/>
+  </target>
+
+</project>