Fix issue spotbugs#79

spotbugs-tests/src/test/java/edu/umd/cs/findbugs/detect/Issue79Test.java

@@ -0,0 +1,28 @@
+package edu.umd.cs.findbugs.detect;
+
+import edu.umd.cs.findbugs.AbstractIntegrationTest;
+import edu.umd.cs.findbugs.BugInstance;
+import edu.umd.cs.findbugs.test.matcher.BugInstanceMatcher;
+import edu.umd.cs.findbugs.test.matcher.BugInstanceMatcherBuilder;
+import org.junit.Test;
+
+import static edu.umd.cs.findbugs.test.CountMatcher.containsExactly;
+import static org.junit.Assert.assertThat;
+
+/**
+ * SpotBugs should remove the ResultSet obligation from all set
+ * when one occurrence of that type of obligation is Statement
+ * from all states.
+ *
+ * @see <a href="https://github.com/spotbugs/spotbugs/issues/79">GitHub issue</a>
+ * @since 4.1.3
+ */
+public class Issue79Test extends AbstractIntegrationTest {
+
+    @Test
+    public void test(){
+        performAnalysis("ghIssues/Issue79.class");
+        BugInstanceMatcher bugMatcher = new BugInstanceMatcherBuilder().build();
+        assertThat(getBugCollection(), containsExactly(0, bugMatcher));
+    }
+}

spotbugs/src/main/java/edu/umd/cs/findbugs/ba/obl/ObligationAnalysis.java

@@ -215,6 +215,17 @@ public void edgeTransfer(Edge edge, StateSet fact) throws DataflowAnalysisExcept
                             + edge.getSource().getLastInstruction());
                 }
                 fact.deleteObligation(comparedObligation, edge.getTarget().getLabel());
+
+                // closing a Statement closes the ResultSet
+                Obligation statement = database.getFactory().getObligationByName("java.sql.Statement");
+                if (comparedObligation.equals(statement)){
+                    Obligation resultSet = database.getFactory().getObligationByName("java.sql.ResultSet");
+                    fact.deleteObligation(resultSet, edge.getTarget().getLabel());
+                    if (DEBUG_NULL_CHECK) {
+                        System.out.println("Deleting " + resultSet.toString() + " on edge from comparison "
+                                + edge.getSource().getLastInstruction());
+                    }
+                }
             }
         }
     }

spotbugsTestCases/src/java/ghIssues/Issue79.java

@@ -0,0 +1,30 @@
+package ghIssues;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+public class Issue79 {
+    private static final String QUERY = "";
+
+    public void f(Connection cnx) throws SQLException {
+        PreparedStatement st = null;
+        ResultSet rs = null;
+        try {
+            st = cnx.prepareStatement(QUERY);
+            rs = st.executeQuery();
+            while (rs.next()) {
+                System.out.println(rs.getString("ID"));
+            }
+        } finally {
+            /*
+             * The statement closes the result set, and there is no scenario where st may be null
+             * but not the resultset, however an unsatisfied obligation is reported on the resultset
+             */
+            if (st != null) {
+                st.close();
+            }
+        }
+    }
+}