text: /**
   *    Copyright (C) 2013 10gen Inc.
   *
   *    This program is free software: you can redistribute it and/or  modify
   *    it under the terms of the GNU Affero General Public License, version 3,
   *    as published by the Free Software Foundation.
   *
   *    This program is distributed in the hope that it will be useful,
   *    but WITHOUT ANY WARRANTY; without even the implied warranty of
   *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *    GNU Affero General Public License for more details.
   *
   *    You should have received a copy of the GNU Affero General Public License
   *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
   *
   *    As a special exception, the copyright holders give permission to link the
   *    code of portions of this program with the OpenSSL library under certain
   *    conditions as described in each individual source file and distribute
   *    linked combinations including the program with the OpenSSL library. You
   *    must comply with the GNU Affero General Public License in all respects for
   *    all of the code used other than as permitted herein. If you modify file(s)
   *    with this exception, you may extend this exception to your version of the
   *    file(s), but you are not obligated to do so. If you do not wish to do so,
   *    delete this exception statement from your version. If you delete this
   *    exception statement from all source files in the program, then also delete
   *    it in the license file.
   */
  
  
  #include "mongo/db/ops/modifier_pull.h"
  
  #include <cstdint>
  
  #include "mongo/base/string_data.h"
  #include "mongo/bson/mutable/document.h"
  #include "mongo/bson/mutable/mutable_bson_test_utils.h"
  #include "mongo/db/jsobj.h"
  #include "mongo/db/json.h"
  #include "mongo/db/ops/log_builder.h"
  #include "mongo/db/query/collation/collator_interface_mock.h"
  #include "mongo/unittest/unittest.h"
  
  namespace {
  
  using mongo::BSONObj;
  using mongo::CollatorInterface;
  using mongo::CollatorInterfaceMock;
  using mongo::LogBuilder;
  using mongo::ModifierInterface;
  using mongo::ModifierPull;
  using mongo::Status;
  using mongo::StringData;
  using mongo::fromjson;
  using mongo::mutablebson::Document;
  using mongo::mutablebson::Element;
  
  /** Helper to build and manipulate a $pull mod. */
  class Mod {
  public:
      Mod() : _mod() {}
  
      explicit Mod(BSONObj modObj) : _modObj(modObj), _mod() {
          ASSERT_OK(_mod.init(_modObj["$pull"].embeddedObject().firstElement(),
                              ModifierInterface::Options::normal()));
      }
  
      Mod(BSONObj modObj, const CollatorInterface* collator) : _modObj(modObj), _mod() {
          ASSERT_OK(_mod.init(_modObj["$pull"].embeddedObject().firstElement(),
                              ModifierInterface::Options::normal(collator)));
      }
  
      Status prepare(Element root, StringData matchedField, ModifierInterface::ExecInfo* execInfo) {
          return _mod.prepare(root, matchedField, execInfo);
      }
  
      Status apply() const {
          return _mod.apply();
      }
  
      Status log(LogBuilder* logBuilder) const {
          return _mod.log(logBuilder);
      }
  
      ModifierPull& mod() {
          return _mod;
      }
  
  private:
      BSONObj _modObj;
      ModifierPull _mod;
  };
  
  TEST(SimpleMod, PrepareOKTargetNotFound) {
      Document doc(fromjson("{}"));
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_TRUE(execInfo.noOp);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $unset : { a : true } }"), logDoc);
  }
  
  TEST(SimpleMod, PrepareOKTargetFound) {
      Document doc(fromjson("{ a : [ 0, 1, 2, 3 ] }"));
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  }
  
  TEST(SimpleMod, PrepareInvalidTargetString) {
      Document doc(fromjson("{ a : 'foo' }"));
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_NOT_OK(mod.prepare(doc.root(), "", &execInfo));
  }
  
  TEST(SimpleMod, PrepareInvalidTargetObject) {
      Document doc(fromjson("{ a : { 'foo' : 'bar' } }"));
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_NOT_OK(mod.prepare(doc.root(), "", &execInfo));
  }
  
  TEST(SimpleMod, PrepareAndLogEmptyDocument) {
      Document doc(fromjson("{}"));
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_TRUE(execInfo.noOp);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $unset : { a : true } }"), logDoc);
  }
  
  TEST(SimpleMod, PrepareAndLogMissingElementAfterFoundPath) {
      Document doc(fromjson("{ a : { b : { c : {} } } }"));
      Mod mod(fromjson("{ $pull : { 'a.b.c.d' : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a.b.c.d");
      ASSERT_TRUE(execInfo.noOp);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $unset : { 'a.b.c.d' : true } }"), logDoc);
  }
  
  TEST(SimpleMod, PrepareAndLogEmptyArray) {
      Document doc(fromjson("{ a : [] }"));
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_TRUE(execInfo.noOp);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $set : { a : [] } }"), logDoc);
  }
  
  TEST(SimpleMod, PullMatchesNone) {
      Document doc(fromjson("{ a : [2, 3, 4, 5] }"));
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_TRUE(execInfo.noOp);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $set : { a : [2, 3, 4, 5] } }"), logDoc);
  }
  
  TEST(SimpleMod, ApplyAndLogPullMatchesOne) {
      Document doc(fromjson("{ a : [0, 1, 2, 3, 4, 5] }"));
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson("{ a : [ 1, 2, 3, 4, 5 ] }"), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $set : { a : [1, 2, 3, 4, 5] } }"), logDoc);
  }
  
  TEST(SimpleMod, ApplyAndLogPullMatchesSeveral) {
      Document doc(fromjson("{ a : [0, 1, 0, 2, 0, 3, 0, 4, 0, 5] }"));
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson("{ a : [ 1, 2, 3, 4, 5 ] }"), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $set : { a : [1, 2, 3, 4, 5] } }"), logDoc);
  }
  
  TEST(SimpleMod, ApplyAndLogPullMatchesAll) {
      Document doc(fromjson("{ a : [0, -1, -2, -3, -4, -5] }"));
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson("{ a : [] }"), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $set : { a : [] } }"), logDoc);
  }
  
  TEST(SimpleMod, PullRespectsTheCollation) {
      Document doc(fromjson("{ a : ['zaa', 'zcc', 'zbb', 'zee'] }"));
      CollatorInterfaceMock collator(CollatorInterfaceMock::MockType::kReverseString);
      Mod mod(fromjson("{ $pull : { a : { $gt : 'abc' } } }"), &collator);
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson("{ a : ['zaa', 'zbb'] }"), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $set : { a : ['zaa', 'zbb'] } }"), logDoc);
  }
  
  TEST(SimpleMod, CollationHasNoAffectWhenPullingNonStrings) {
      Document doc(fromjson("{ a : [0, -1, -2, -3, -4, -5] }"));
      CollatorInterfaceMock collator(CollatorInterfaceMock::MockType::kReverseString);
      Mod mod(fromjson("{ $pull : { a : { $lt : 1 } } }"), &collator);
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson("{ a : [] }"), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $set : { a : [] } }"), logDoc);
  }
  
  TEST(SimpleMod, CollationHasNoAffectWhenPullingStringsUsingRegex) {
      Document doc(fromjson("{ a : ['b', 'a', 'aab', 'cb', 'bba'] }"));
      CollatorInterfaceMock collator(CollatorInterfaceMock::MockType::kAlwaysEqual);
      Mod mod(fromjson("{ $pull : { a : /a/ } }"), &collator);
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson("{ a : ['b', 'cb'] }"), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $set : { a : ['b', 'cb'] } }"), logDoc);
  }
  
  TEST(SimpleMod, PullingBasedOnStringLiteralRespectsCollation) {
      Document doc(fromjson("{ a : ['a', 'b', 'c', 'd'] }"));
      CollatorInterfaceMock collator(CollatorInterfaceMock::MockType::kAlwaysEqual);
      Mod mod(fromjson("{ $pull : { a : 'c' } }"), &collator);
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson("{ a : [] }"), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $set : { a : [] } }"), logDoc);
  }
  
  TEST(SimpleMod, PullingBasedOnNumberLiteralNotAffectedByCollation) {
      Document doc(fromjson("{ a : ['a', 99, 'b', 2, 'c', 99, 'd'] }"));
      CollatorInterfaceMock collator(CollatorInterfaceMock::MockType::kAlwaysEqual);
      Mod mod(fromjson("{ $pull : { a : 99 } }"), &collator);
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson("{ a : ['a', 'b', 2, 'c', 'd'] }"), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson("{ $set : { a : ['a', 'b', 2, 'c', 'd'] } }"), logDoc);
  }
  
  TEST(ComplexMod, ApplyAndLogComplexDocAndMatching1) {
      const char* const strings[] = {
          // Document:
          "{ a : { b : [ { x : 1 }, { y : 'y' }, { x : 2 }, { z : 'z' } ] } }",
  
          // Modifier:
          "{ $pull : { 'a.b' : { $or : [ "
          "  { 'y' : { $exists : true } }, "
          "  { 'z' : { $exists : true } } "
          "] } } }",
  
          // Document result:
          "{ a : { b : [ { x : 1 }, { x : 2 } ] } }",
  
          // Log result:
          "{ $set : { 'a.b' : [ { x : 1 }, { x : 2 } ] } }"};
  
      Document doc(fromjson(strings[0]));
      Mod mod(fromjson(strings[1]));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a.b");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  TEST(ComplexMod, ApplyAndLogComplexDocAndMatching2) {
      const char* const strings[] = {
          // Document:
          "{ a : { b : [ { x : 1 }, { y : 'y' }, { x : 2 }, { z : 'z' } ] } }",
  
          // Modifier:
          "{ $pull : { 'a.b' : { 'y' : { $exists : true } } } }",
  
          // Document result:
          "{ a : { b : [ { x : 1 }, { x : 2 }, { z : 'z' } ] } }",
  
          // Log result:
          "{ $set : { 'a.b' : [ { x : 1 }, { x : 2 }, { z : 'z' } ] } }"};
  
      Document doc(fromjson(strings[0]));
      Mod mod(fromjson(strings[1]));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a.b");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  TEST(ComplexMod, ApplyAndLogComplexDocAndMatching3) {
      const char* const strings[] = {
          // Document:
          "{ a : { b : [ { x : 1 }, { y : 'y' }, { x : 2 }, { z : 'z' } ] } }",
  
          // Modifier:
          "{ $pull : { 'a.b' : { $in : [ { x : 1 }, { y : 'y' } ] } } }",
  
          // Document result:
          "{ a : { b : [ { x : 2 }, { z : 'z' } ] } }",
  
          // Log result:
          "{ $set : { 'a.b' : [ { x : 2 }, { z : 'z' } ] } }"};
  
      Document doc(fromjson(strings[0]));
      Mod mod(fromjson(strings[1]));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a.b");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  TEST(ComplexMod, FullPredicateInsidePullRespectsCollation) {
      const char* const strings[] = {
          // Document:
          "{ a : { b : [ { x : 'foo', y : 1 }, { x : 'bar', y : 2 }, { x : 'baz', y : 3 } ] } }",
  
          // Modifier:
          "{ $pull : { 'a.b' : { x : 'blah' } } }",
  
          // Document result:
          "{ a : { b : [ ] } }",
  
          // Log result:
          "{ $set : { 'a.b' : [ ] } }"};
  
      Document doc(fromjson(strings[0]));
  
      CollatorInterfaceMock collator(CollatorInterfaceMock::MockType::kAlwaysEqual);
      Mod mod(fromjson(strings[1]), &collator);
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a.b");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  TEST(ValueMod, ApplyAndLogScalarValueMod) {
      const char* const strings[] = {// Document:
                                     "{ a : [1, 2, 1, 2, 1, 2] }",
  
                                     // Modifier:
                                     "{ $pull : { a : 1 } }",
  
                                     // Document result:
                                     "{ a : [ 2, 2, 2] }",
  
                                     // Log result:
                                     "{ $set : { a : [ 2, 2, 2 ] } }"};
  
      Document doc(fromjson(strings[0]));
      Mod mod(fromjson(strings[1]));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  TEST(ValueMod, ApplyAndLogObjectValueMod) {
      const char* const strings[] = {// Document:
                                     "{ a : [ { x : 1 }, { y : 2 }, { x : 1 }, { y : 2 } ] }",
  
                                     // Modifier:
                                     "{ $pull : { a : { y : 2 } } }",
  
                                     // Document result:
                                     "{ a : [ { x : 1 }, { x : 1 }] }",
  
                                     // Log result:
                                     "{ $set : { a : [ { x : 1 }, { x : 1 } ] } }"};
  
      Document doc(fromjson(strings[0]));
      Mod mod(fromjson(strings[1]));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  TEST(DocumentationTests, Example1) {
      const char* const strings[] = {
          // Document:
          "{ flags: ['vme', 'de', 'pse', 'tsc', 'msr', 'pae', 'mce' ] }",
  
          // Modifier:
          "{ $pull: { flags: 'msr' } }",
  
          // Document result:
          "{ flags: ['vme', 'de', 'pse', 'tsc', 'pae', 'mce' ] }",
  
          // Log result:
          "{ $set : { flags: ['vme', 'de', 'pse', 'tsc', 'pae', 'mce' ] } }"};
  
      Document doc(fromjson(strings[0]));
      Mod mod(fromjson(strings[1]));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "flags");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  TEST(DocumentationTests, Example2a) {
      const char* const strings[] = {// Document:
                                     "{ votes: [ 3, 5, 6, 7, 7, 8 ] }",
  
                                     // Modifier:
                                     "{ $pull: { votes: 7 } }",
  
                                     // Document result:
                                     "{ votes: [ 3, 5, 6, 8 ] }",
  
                                     // Log result:
                                     "{ $set : { votes: [ 3, 5, 6, 8 ] } }"};
  
      Document doc(fromjson(strings[0]));
      Mod mod(fromjson(strings[1]));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "votes");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  TEST(DocumentationTests, Example2b) {
      const char* const strings[] = {// Document:
                                     "{ votes: [ 3, 5, 6, 7, 7, 8 ] }",
  
                                     // Modifier:
                                     "{ $pull: { votes: { $gt: 6 } } }",
  
                                     // Document result:
                                     "{ votes: [ 3, 5, 6 ] }",
  
                                     // Log result:
                                     "{ $set : { votes: [ 3, 5, 6 ] } }"};
  
      Document doc(fromjson(strings[0]));
      Mod mod(fromjson(strings[1]));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "votes");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  TEST(MatchingEdgeCases, NonObjectShortCircuit) {
      const char* const strings[] = {
          "{ a: [ { x: 1 }, 2 ] }",
  
          "{ $pull: { a: { x: 1 } } }",
  
          "{ a: [ 2 ] }",
  
          "{ $set : { a: [ 2 ] } }",
      };
  
      Document doc(fromjson(strings[0]));
      Mod mod(fromjson(strings[1]));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "a");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  TEST(MatchingRegressions, SERVER_3988) {
      const char* const strings[] = {
          "{ x: 1, y: [ 2, 3, 4, 'abc', 'xyz' ] }",
  
          "{ $pull: { y: /yz/ } }",
  
          "{ x: 1, y: [ 2, 3, 4, 'abc' ] }",
  
          "{ $set : { y: [ 2, 3, 4, 'abc' ] } }",
      };
  
      Document doc(fromjson(strings[0]));
      Mod mod(fromjson(strings[1]));
  
      ModifierInterface::ExecInfo execInfo;
      ASSERT_OK(mod.prepare(doc.root(), "", &execInfo));
      ASSERT_EQUALS(execInfo.fieldRef[0]->dottedField(), "y");
      ASSERT_FALSE(execInfo.noOp);
  
      ASSERT_OK(mod.apply());
      ASSERT_FALSE(doc.isInPlaceModeEnabled());
      ASSERT_EQUALS(fromjson(strings[2]), doc);
  
      Document logDoc;
      LogBuilder logBuilder(logDoc.root());
      ASSERT_OK(mod.log(&logBuilder));
      ASSERT_EQUALS(fromjson(strings[3]), logDoc);
  }
  
  }  // namespace
  