fixed NPE when no build has run yet.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@1727 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/model/Job.java

@@ -32,6 +32,7 @@ import org.kohsuke.stapler.StaplerRequest;
 import org.kohsuke.stapler.StaplerResponse;
 
 import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletResponse;
 import java.awt.Color;
 import java.awt.Paint;
 import java.io.File;
@@ -558,6 +559,10 @@ public abstract class Job<JobT extends Job<JobT,RunT>, RunT extends Run<JobT,Run
      * Returns the graph that shows how long each build took.
      */
     public void doBuildTimeGraph( StaplerRequest req, StaplerResponse rsp ) throws IOException {
+        if(getLastBuild()==null) {
+            rsp.setStatus(HttpServletResponse.SC_NOT_FOUND);
+            return;
+        }
         if(req.checkIfModified(getLastBuild().getTimestamp(),rsp))
             return;
         ChartUtil.generateGraph(req,rsp, createBuildTimeTrendChart(),500,400);
@@ -568,6 +573,10 @@ public abstract class Job<JobT extends Job<JobT,RunT>, RunT extends Run<JobT,Run
      * Loaded lazily by AJAX.
      */
     public void doBuildTimeGraphMap( StaplerRequest req, StaplerResponse rsp ) throws IOException {
+        if(getLastBuild()==null) {
+            rsp.setStatus(HttpServletResponse.SC_NOT_FOUND);
+            return;
+        }
         if(req.checkIfModified(getLastBuild().getTimestamp(),rsp))
             return;
         ChartUtil.generateClickableMap(req,rsp, createBuildTimeTrendChart(),500,400);

core/src/main/resources/hudson/model/Job/buildTimeTrend.jelly

@@ -3,37 +3,44 @@
   <l:layout title="Build time trend">
 		<st:include page="sidepanel.jelly" />
 		<l:main-panel>
-      <div align="center">
-        <img src="buildTimeGraph" width="500" height="400" lazymap="buildTimeGraphMap"/>
-      </div>
+      <j:choose>
+        <j:when test="${it.builds.size()&gt;1">
+          <div align="center">
+            <img src="buildTimeGraph" width="500" height="400" lazymap="buildTimeGraphMap"/>
+          </div>
 
-      <j:set var="isMasterSlaveEnabled" value="${!empty(app.slaves)}"/>
-      <div align="center">
-        <table class="sortable" style="margin-top:1em;">
-          <tr>
-            <th initialSortDir="up">Build</th>
-            <th>Duration</th>
-            <j:if test="${isMasterSlaveEnabled}">
-              <th>Slave</th>
-            </j:if>
-          </tr>
-          <j:forEach var="r" items="${it.builds}">
-            <tr>
-              <td>
-                ${r.displayName}
-              </td>
-              <td data="${r.duration}">
-                ${r.durationString}
-              </td>
-              <j:if test="${isMasterSlaveEnabled}">
-                <td>
-                  <t:node value="${r.builtOn}"/>
-                </td>
-              </j:if>
-            </tr>
-          </j:forEach>
-        </table>
-      </div>
+          <j:set var="isMasterSlaveEnabled" value="${!empty(app.slaves)}"/>
+          <div align="center">
+            <table class="sortable" style="margin-top:1em;">
+              <tr>
+                <th initialSortDir="up">Build</th>
+                <th>Duration</th>
+                <j:if test="${isMasterSlaveEnabled}">
+                  <th>Slave</th>
+                </j:if>
+              </tr>
+              <j:forEach var="r" items="${it.builds}">
+                <tr>
+                  <td>
+                    ${r.displayName}
+                  </td>
+                  <td data="${r.duration}">
+                    ${r.durationString}
+                  </td>
+                  <j:if test="${isMasterSlaveEnabled}">
+                    <td>
+                      <t:node value="${r.builtOn}"/>
+                    </td>
+                  </j:if>
+                </tr>
+              </j:forEach>
+            </table>
+          </div>
+        </j:when>
+        <j:otherwise>
+          More than 1 builds are needed for the trend report.
+        </j:otherwise>
+      </j:choose>
     </l:main-panel>
 	</l:layout>
 </j:jelly>
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