[JENKINS-17681] Set up a test which passes on Unix but fails on Windows when...

[JENKINS-17681] Set up a test which passes on Unix but fails on Windows when symlinks are enabled on the platform but disabled for the current user.

core/src/main/java/jenkins/model/PeepholePermalink.java

@@ -81,12 +81,7 @@ public abstract class PeepholePermalink extends Permalink implements Predicate<R
         Run<?,?> b=null;
 
         try {
-            String target = Util.resolveSymlink(f);
-            if (target==null && f.exists()) {
-                // if this file isn't a symlink, it must be a regular file
-                target = FileUtils.readFileToString(f,"UTF-8").trim();
-            }
-
+            String target = readSymlink(f);
             if (target!=null) {
                 int n = Integer.parseInt(Util.getFileName(target));
                 if (n==RESOLVES_TO_NONE)  return null;
@@ -135,19 +130,39 @@ public abstract class PeepholePermalink extends Permalink implements Predicate<R
         final int n = b==null ? RESOLVES_TO_NONE : b.getNumber();
 
         File cache = getPermalinkFile(job);
-        File tmp = new File(cache.getPath()+".tmp");
         cache.getParentFile().mkdirs();
 
         try {
-            StringWriter w = new StringWriter();
-            StreamTaskListener listener = new StreamTaskListener(w);
+            writeSymlink(cache, String.valueOf(n));
+        } catch (IOException e) {
+            LOGGER.log(Level.WARNING, "Failed to update "+job+" "+getId()+" permalink for " + b, e);
+            cache.delete();
+        } catch (InterruptedException e) {
+            LOGGER.log(Level.WARNING, "Failed to update "+job+" "+getId()+" permalink for " + b, e);
+            cache.delete();
+        }
+    }
 
-            Util.createSymlink(tmp.getParentFile(),String.valueOf(n),tmp.getName(),listener);
+    static String readSymlink(File cache) throws IOException, InterruptedException {
+        String target = Util.resolveSymlink(cache);
+        if (target==null && cache.exists()) {
+            // if this file isn't a symlink, it must be a regular file
+            target = FileUtils.readFileToString(cache,"UTF-8").trim();
+        }
+        return target;
+    }
+
+    static void writeSymlink(File cache, String target) throws IOException, InterruptedException {
+        StringWriter w = new StringWriter();
+        StreamTaskListener listener = new StreamTaskListener(w);
+        File tmp = new File(cache.getPath()+".tmp");
+        try {
+            Util.createSymlink(tmp.getParentFile(),target,tmp.getName(),listener);
             if (Util.resolveSymlink(tmp)==null) {
                 // symlink not supported. use a regular file
                 AtomicFileWriter cw = new AtomicFileWriter(cache);
                 try {
-                    cw.write(String.valueOf(n));
+                    cw.write(target);
                     cw.commit();
                 } finally {
                     cw.abort();
@@ -156,12 +171,6 @@ public abstract class PeepholePermalink extends Permalink implements Predicate<R
                 cache.delete();
                 tmp.renameTo(cache);
             }
-        } catch (IOException e) {
-            LOGGER.log(Level.WARNING, "Failed to update "+job+" "+getId()+" permalink for " + b, e);
-            cache.delete();
-        } catch (InterruptedException e) {
-            LOGGER.log(Level.WARNING, "Failed to update "+job+" "+getId()+" permalink for " + b, e);
-            cache.delete();
         } finally {
             tmp.delete();
         }

core/src/test/java/jenkins/model/PeepholePermalinkTest.java

+/*
+ * The MIT License
+ *
+ * Copyright 2013 Jesse Glick.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package jenkins.model;
+
+import java.io.File;
+import org.junit.Test;
+import static org.junit.Assert.*;
+import org.junit.Rule;
+import org.junit.rules.TemporaryFolder;
+import org.jvnet.hudson.test.Bug;
+
+public class PeepholePermalinkTest {
+
+    @Rule public TemporaryFolder tmp = new TemporaryFolder();
+
+    @Bug(17681)
+    @Test public void symlinks() throws Exception {
+        File link = new File(tmp.getRoot(), "link");
+        PeepholePermalink.writeSymlink(link, "stuff");
+        assertEquals("stuff", PeepholePermalink.readSymlink(link));
+    }
+
+}