[FIXED HUDSON-6497] slightly revised the patch, to avoid using a boolean flag...

[FIXED HUDSON-6497] slightly revised the patch, to avoid using a boolean flag for a concurrency control. It affects the serialization format, and it's not concurrency safe.

Given the use case described in the bug, I wonder if it's better to have a different extension point (sort of like ComputerListener) that can contribute build variables to any builds going on in the system.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@32257 71c3de6d-444a-0410-be80-ed276b4c234a

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

@@ -740,6 +740,13 @@ public abstract class AbstractBuild<P extends AbstractProject<P,R>,R extends Abs
                 if (v!=null) r.put(p.getName(),v);
             }
         }
+
+        // allow the BuildWrappers to contribute additional build variables
+        if (project instanceof BuildableItemWithBuildWrappers) {
+            for (BuildWrapper bw : ((BuildableItemWithBuildWrappers) project).getBuildWrappersList())
+                bw.makeBuildVariables(this,r);
+        }
+
         return r;
     }
 

core/src/main/java/hudson/tasks/BuildWrapper.java

@@ -33,6 +33,7 @@ import hudson.model.Run.RunnerAbortedException;
 import java.io.IOException;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.Map;
 
 /**
  * Pluggability point for performing pre/post actions for the build process.
@@ -203,6 +204,22 @@ public abstract class BuildWrapper extends AbstractDescribableImpl<BuildWrapper>
         return Collections.singletonList(a);
     }
 
+    /**
+     * Called to define {@linkplain AbstractBuild#getBuildVariables()}.
+     *
+     * This provides an opportunity for a BuildWrapper to append any additional
+     * build variables defined for the current build.
+     * 
+     * @param build
+     *      The build in progress for which this {@link BuildWrapper} is called. Never null.
+     * @param variables
+     *      Contains existing build variables. Add additional build variables that you contribute
+     *      to this map.
+     */
+    public void makeBuildVariables(AbstractBuild build, Map<String,String> variables) {
+    	// noop
+    }
+
     /**
      * Returns all the registered {@link BuildWrapper} descriptors.
      */