Handle case where last completed build does not have RebuildAction

[sghill]

This fixes a NPE introduced in #155. We've run into this issue while attempting to view job config history with the latest version, and have pinned to the previous version to avoid it.

Testing done

I attempted to create a tests with mockito that covered the logic of RebuildLastCompletedBuildAction#getUrlName(), but ran into issues with Jenkins.instance missing. Since the change here is straightforward, I wasn't sure it warranted creating JenkinsRule tests.

RebuildLastCompletedBuildActionTest.java

package com.sonyericsson.rebuild;

import hudson.model.AbstractProject;
import hudson.model.FreeStyleBuild;
import hudson.model.FreeStyleProject;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mock;
import org.mockito.junit.MockitoJUnitRunner;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;
import static org.mockito.BDDMockito.given;

@RunWith(MockitoJUnitRunner.class)
public class RebuildLastCompletedBuildActionTest {
    @Mock
    private AbstractProject project;
    @Mock
    private FreeStyleBuild lastCompletedBuild;
    @Mock
    private RebuildAction rebuildAction;
    private RebuildLastCompletedBuildAction action;

    @Before
    public void setUp() {
        action = new RebuildLastCompletedBuildAction(project);
    }

    @Test
    public void shouldReturnNullIfNotBuildable() {
        given(project.isBuildable()).willReturn(false);
        String actual = action.getUrlName();
        assertNull(actual);
    }

    @Test
    public void shouldReturnNullIfNoLastCompletedBuild() {
        given(project.isBuildable()).willReturn(true);
        given(project.getLastCompletedBuild()).willReturn(null);
        String actual = action.getUrlName();
        assertNull(actual);
    }

    @Test
    public void shouldReturnNullIfNoRebuildActionOnLastCompletedBuild() {
        given(project.isBuildable()).willReturn(true);
        given(project.getLastCompletedBuild()).willReturn(lastCompletedBuild);
        given(lastCompletedBuild.getAction(RebuildAction.class)).willReturn(null);
        String actual = action.getUrlName();
        assertNull(actual);
    }

    @Test
    public void shouldReturnUrlName() {
        given(project.isBuildable()).willReturn(true);
        given(project.getLastCompletedBuild()).willReturn(lastCompletedBuild);
        given(rebuildAction.getUrlName()).willReturn("expected-task-url");
        given(lastCompletedBuild.getAction(RebuildAction.class)).willReturn(rebuildAction);
        String expected = "lastCompletedBuild/expected-task-url";
        String actual = action.getUrlName();
        assertEquals(expected, actual);
    }
}

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[daniel-beck]

I would not expect this to happen with RebuildActionFactory. What's the affected job type?

[sghill]

@daniel-beck it's a hudson.model.FreeStyleProject that was created before the upgrade. Loading up {buildUrl}/jobConfigHistory/ showed this stacktrace:

Caused by: java.lang.NullPointerException: Cannot invoke "com.sonyericsson.rebuild.RebuildAction.getTaskUrl()" because "action" is null
        at com.sonyericsson.rebuild.RebuildLastCompletedBuildAction.getUrlName(RebuildLastCompletedBuildAction.java:61)
        at hudson.model.Actionable.getDynamic(Actionable.java:345)
        at hudson.model.Job.getDynamic(Job.java:864)
        at java.base/java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:732)
        at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:397)

[daniel-beck]

My guess is you have a plugin installed that provides an implementation of RebuildValidator, like gerrit-trigger. That's a case I didn't test for as I was unaware this existed.

[GLundh]

@daniel-beck: I don't see much risk for this PR. But before I merge & close, do you see a risk?

[daniel-beck]

@GLundh Untested but seems fine if it works. Feedback was exclusively about understanding how this situation occurs.

[sghill]

Confirming I do have another implementation of RebuildValidator.

Thanks for the review!

[pci-mthompson]

FYI, this can also occur with inheritance builds (Project Inheritance Plugin) after recent updates. I manually patched a version of rebuild and this PR fixes it.

[shemuwel]

Hello! Any chance to get this PR merged?
Thank you

[hagzag]

LGTM

[timotei]

@hagzag can we make use of this fix in a released version? We're currently blocked from rolling out the latest update because of this issue.