Add tests for Prolog's handling of SubmitRecords

Prolog handles the results of the defined `submit_rule` in a specific
way: once an OK record is found, processing of the other SubmitRecords
is stopped. This leads to weird situations, for instance if we have a
*not_ready* record _before_ the *ok* one.

Add a test to ensure the behavior isn't changed inadvertently and to
document it with simple and reproducible test cases.

Change-Id: I06d054a47c47e05d3e453e4520474cc2d26c98e4

java/com/google/gerrit/server/project/SubmitRuleEvaluator.java

@@ -252,7 +252,7 @@ public class SubmitRuleEvaluator {
    * output. Later after the loop the out collection is reversed to restore it to the original
    * ordering.
    */
-  private List<SubmitRecord> resultsToSubmitRecord(Term submitRule, List<Term> results) {
+  public List<SubmitRecord> resultsToSubmitRecord(Term submitRule, List<Term> results) {
     List<SubmitRecord> out = new ArrayList<>(results.size());
     for (int resultIdx = results.size() - 1; 0 <= resultIdx; resultIdx--) {
       Term submitRecord = results.get(resultIdx);

javatests/com/google/gerrit/acceptance/server/project/BUILD

@@ -4,4 +4,7 @@ acceptance_tests(
     srcs = glob(["*IT.java"]),
     group = "server_project",
     labels = ["server"],
+    deps = [
+        "@prolog_runtime//jar",
+    ],
 )

javatests/com/google/gerrit/acceptance/server/project/SubmitRulesEvaluatorIT.java

@@ -0,0 +1,156 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.acceptance.server.project;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.collect.ImmutableList;
+import com.google.gerrit.acceptance.AbstractDaemonTest;
+import com.google.gerrit.acceptance.TestAccount;
+import com.google.gerrit.common.data.SubmitRecord;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.server.project.SubmitRuleEvaluator;
+import com.google.gerrit.server.query.change.ChangeData;
+import com.google.gerrit.testing.TestChanges;
+import com.google.inject.Inject;
+import com.googlecode.prolog_cafe.lang.IntegerTerm;
+import com.googlecode.prolog_cafe.lang.StructureTerm;
+import com.googlecode.prolog_cafe.lang.Term;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import org.junit.Test;
+
+public class SubmitRulesEvaluatorIT extends AbstractDaemonTest {
+  @Inject private SubmitRuleEvaluator.Factory evaluatorFactory;
+
+  @Test
+  public void convertsPrologToSubmitRecord() {
+    SubmitRuleEvaluator evaluator = makeEvaluator();
+
+    StructureTerm verifiedLabel = makeLabel("Verified", "may");
+    StructureTerm labels = new StructureTerm("label", verifiedLabel);
+
+    List<Term> terms = ImmutableList.of(makeTerm("ok", labels));
+    Collection<SubmitRecord> records = evaluator.resultsToSubmitRecord(null, terms);
+
+    assertThat(records).hasSize(1);
+  }
+
+  /**
+   * The Prolog behavior is everything but intuitive. Several submit_rules can be defined, and each
+   * will provide a different SubmitRecord answer when queried. The current implementation stops
+   * parsing the Prolog terms into SubmitRecord objects once it finds an OK record. This might lead
+   * to tangling results, as reproduced by this test.
+   *
+   * <p>Let's consider this rules.pl file (equivalent to the code in this test)
+   *
+   * <pre>{@code
+   * submit_rule(submit(R)) :-
+   *     gerrit:uploader(U),
+   *     R = label('Verified', reject(U)).
+   *
+   * submit_rule(submit(CR, V)) :-
+   *     gerrit:uploader(U),
+   *     V = label('Code-Review', ok(U)).
+   *
+   * submit_rule(submit(R)) :-
+   *     gerrit:uploader(U),
+   *     R = label('Any-Label-Name', reject(U)).
+   * }</pre>
+   *
+   * The first submit_rule always fails because the Verified label is rejected.
+   *
+   * <p>The second submit_rule is always valid, and provides two labels: OK and Code-Review.
+   *
+   * <p>The third submit_rule always fails because the Any-Label-Name label is rejected.
+   *
+   * <p>In this case, the last two SubmitRecords are used, the first one is discarded.
+   */
+  @Test
+  public void abortsEarlyWithOkayRecord() {
+    SubmitRuleEvaluator evaluator = makeEvaluator();
+
+    SubmitRecord.Label submitRecordLabel1 = new SubmitRecord.Label();
+    submitRecordLabel1.label = "Verified";
+    submitRecordLabel1.status = SubmitRecord.Label.Status.REJECT;
+    submitRecordLabel1.appliedBy = admin.id;
+
+    SubmitRecord.Label submitRecordLabel2 = new SubmitRecord.Label();
+    submitRecordLabel2.label = "Code-Review";
+    submitRecordLabel2.status = SubmitRecord.Label.Status.OK;
+    submitRecordLabel2.appliedBy = admin.id;
+
+    SubmitRecord.Label submitRecordLabel3 = new SubmitRecord.Label();
+    submitRecordLabel3.label = "Any-Label-Name";
+    submitRecordLabel3.status = SubmitRecord.Label.Status.REJECT;
+    submitRecordLabel3.appliedBy = user.id;
+
+    List<Term> terms = new ArrayList<>();
+
+    StructureTerm label1 = makeLabel(submitRecordLabel1.label, "reject", admin);
+
+    StructureTerm label2 = makeLabel(submitRecordLabel2.label, "ok", admin);
+
+    StructureTerm label3 = makeLabel(submitRecordLabel3.label, "reject", user);
+
+    terms.add(makeTerm("not_ready", makeLabels(label1)));
+    terms.add(makeTerm("ok", makeLabels(label2)));
+    terms.add(makeTerm("not_ready", makeLabels(label3)));
+
+    // When
+    List<SubmitRecord> records = evaluator.resultsToSubmitRecord(null, terms);
+
+    // assert that
+    SubmitRecord record1Expected = new SubmitRecord();
+    record1Expected.status = SubmitRecord.Status.OK;
+    record1Expected.labels = new ArrayList<>();
+    record1Expected.labels.add(submitRecordLabel2);
+
+    SubmitRecord record2Expected = new SubmitRecord();
+    record2Expected.status = SubmitRecord.Status.NOT_READY;
+    record2Expected.labels = new ArrayList<>();
+    record2Expected.labels.add(submitRecordLabel3);
+
+    assertThat(records).hasSize(2);
+
+    assertThat(records.get(0)).isEqualTo(record1Expected);
+    assertThat(records.get(1)).isEqualTo(record2Expected);
+  }
+
+  private static Term makeTerm(String status, StructureTerm labels) {
+    return new StructureTerm(status, labels);
+  }
+
+  private static StructureTerm makeLabel(String name, String status) {
+    return new StructureTerm("label", new StructureTerm(name), new StructureTerm(status));
+  }
+
+  private static StructureTerm makeLabel(String name, String status, TestAccount account) {
+    StructureTerm user = new StructureTerm("user", new IntegerTerm(account.id.get()));
+    return new StructureTerm("label", new StructureTerm(name), new StructureTerm(status, user));
+  }
+
+  private static StructureTerm makeLabels(StructureTerm... labels) {
+    return new StructureTerm("label", labels);
+  }
+
+  private SubmitRuleEvaluator makeEvaluator() {
+    ChangeData cd = ChangeData.createForTest(project, new Change.Id(1), 1);
+    cd.setChange(TestChanges.newChange(project, admin.id));
+
+    return evaluatorFactory.create(cd);
+  }
+}

javatests/com/google/gerrit/common/data/SubmitRecordTest.java

@@ -0,0 +1,52 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.common.data;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import org.junit.Test;
+
+public class SubmitRecordTest {
+
+  private static SubmitRecord OK_RECORD;
+  private static SubmitRecord NOT_READY_RECORD;
+
+  static {
+    OK_RECORD = new SubmitRecord();
+    OK_RECORD.status = SubmitRecord.Status.OK;
+
+    NOT_READY_RECORD = new SubmitRecord();
+    NOT_READY_RECORD.status = SubmitRecord.Status.NOT_READY;
+  }
+
+  @Test
+  public void findOkRecord() {
+    Collection<SubmitRecord> submitRecords = new ArrayList<>();
+    submitRecords.add(NOT_READY_RECORD);
+    submitRecords.add(OK_RECORD);
+
+    assertThat(SubmitRecord.findOkRecord(submitRecords).isPresent()).isTrue();
+  }
+
+  @Test
+  public void emptyResultIfInvalid() {
+    Collection<SubmitRecord> submitRecords = new ArrayList<>();
+    submitRecords.add(NOT_READY_RECORD);
+
+    assertThat(SubmitRecord.findOkRecord(submitRecords).isPresent()).isFalse();
+  }
+}