Empty targets are also a problem for the substructure search. Simple …

…checks avoids the infinite loop. Signed-off-by: Egon Willighagen <egonw@users.sourceforge.net>
cdk · Mar 8, 2014 · d9ef27f · d9ef27f
1 parent c1f7b2d
commit d9ef27f
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diff --git a/base/isomorphism/src/main/java/org/openscience/cdk/isomorphism/StateStream.java b/base/isomorphism/src/main/java/org/openscience/cdk/isomorphism/StateStream.java
@@ -61,7 +61,8 @@ final class StateStream implements Iterator<int[]> {
     StateStream(final State state) {
         this.state = state;
         this.stack = new CandidateStack(state.nMax());
-        this.next  = state.nMax() == 0 ? null : findNext(); // first-mapping
+        this.next  = state.nMax() == 0 || state.mMax() == 0 ? null 
+                                                            : findNext(); // first-mapping
     }
 
     /** @inheritDoc */

diff --git a/tool/smarts/src/test/java/org/openscience/cdk/isomorphism/SubstructureTest.java b/tool/smarts/src/test/java/org/openscience/cdk/isomorphism/SubstructureTest.java
@@ -331,6 +331,11 @@ public abstract class SubstructureTest {
         assertMismatch(smi(""),
                        smi("[H][H]"));
     }
+
+    @Test public void emptyTarget() throws Exception {
+        assertMismatch(smi("[H][H]"),
+                       smi(""));
+    }
 
     void assertMatch(IAtomContainer query, IAtomContainer target, int count) {
         assertThat(query.getProperty(TITLE)