extensions/proto/src/main/java/com/google/common/truth/extensions/proto/DiffResult.java

/*
 * Copyright (c) 2017 Google, Inc.
 *
 * 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.common.truth.extensions.proto;

import com.google.auto.value.AutoValue;
import com.google.auto.value.extension.memoized.Memoized;
import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableListMultimap;
import com.google.common.collect.Iterables;
import com.google.common.collect.Ordering;
import com.google.common.collect.Sets;
import com.google.common.truth.extensions.proto.RecursableDiffEntity.WithResultCode.Result;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.ForOverride;
import com.google.protobuf.Descriptors.FieldDescriptor;
import com.google.protobuf.Message;
import com.google.protobuf.TextFormat;
import com.google.protobuf.UnknownFieldSet;
import java.io.IOException;
import java.util.Set;

/**
 * Structural summary of the difference between two messages.
 *
 * <p>A {@code DiffResult} has singular fields, repeated fields, and unknowns, each with their own
 * class. The inner classes may also contain their own {@code DiffResult}s for submessages.
 *
 * <p>These classes form a recursive, hierarchical relationship. Much of the common recursion logic
 * across all the classes is in {@link RecursableDiffEntity}.
 */
@AutoValue
abstract class DiffResult extends RecursableDiffEntity.WithoutResultCode {
  /**
   * Structural summary of the difference between two singular (non-repeated) fields.
   *
   * <p>It is possible for the result to be {@code ADDED} or {@code REMOVED}, even if {@code
   * actual()} and {@code expected()} are identical. This occurs if the config does not have {@link
   * FluentEqualityConfig#ignoringFieldAbsence()} enabled, one message had the field explicitly set
   * to the default value, and the other did not.
   */
  @AutoValue
  abstract static class SingularField extends RecursableDiffEntity.WithResultCode {
    /** The type information for this field. May be absent if result code is {@code IGNORED}. */
    abstract Optional<SubScopeId> subScopeId();

    /** The display name for this field. May include an array-index specifier. */
    abstract String fieldName();

    /** The field under test. */
    abstract Optional<Object> actual();

    /** The expected value of said field. */
    abstract Optional<Object> expected();

    /**
     * The detailed breakdown of the comparison, only present if both objects are set on this
     * instance and they are messages.
     *
     * <p>This does not necessarily mean the messages were set on the input protos.
     */
    abstract Optional<DiffResult> breakdown();

    /**
     * The detailed breakdown of the comparison, only present if both objects are set and they are
     * {@link UnknownFieldSet}s.
     *
     * <p>This will only ever be set inside a parent {@link UnknownFieldSetDiff}. The top {@link
     * UnknownFieldSetDiff} is set on the {@link DiffResult}, not here.
     */
    abstract Optional<UnknownFieldSetDiff> unknownsBreakdown();

    /** Returns {@code actual().get()}, or {@code expected().get()}, whichever is available. */
    @Memoized
    Object actualOrExpected() {
      return actual().or(expected()).get();
    }

    @Memoized
    @Override
    Iterable<? extends RecursableDiffEntity> childEntities() {
      return ImmutableList.copyOf(
          Iterables.concat(breakdown().asSet(), unknownsBreakdown().asSet()));
    }

    @Override
    final void printContents(boolean includeMatches, String fieldPrefix, StringBuilder sb) {
      if (!includeMatches && isMatched()) {
        return;
      }

      fieldPrefix = newFieldPrefix(fieldPrefix, fieldName());
      switch (result()) {
        case ADDED:
          sb.append("added: ").append(fieldPrefix).append(": ");
          if (actual().get() instanceof Message) {
            sb.append("\n").append(actual().get());
          } else {
            sb.append(valueString(subScopeId().get(), actual().get())).append("\n");
          }
          return;
        case IGNORED:
          sb.append("ignored: ").append(fieldPrefix).append("\n");
          return;
        case MATCHED:
          sb.append("matched: ").append(fieldPrefix);
          if (actualOrExpected() instanceof Message) {
            sb.append("\n");
            printChildContents(includeMatches, fieldPrefix, sb);
          } else {
            sb.append(": ")
                .append(valueString(subScopeId().get(), actualOrExpected()))
                .append("\n");
          }
          return;
        case MODIFIED:
          sb.append("modified: ").append(fieldPrefix);
          if (actualOrExpected() instanceof Message) {
            sb.append("\n");
            printChildContents(includeMatches, fieldPrefix, sb);
          } else {
            sb.append(": ")
                .append(valueString(subScopeId().get(), expected().get()))
                .append(" -> ")
                .append(valueString(subScopeId().get(), actual().get()))
                .append("\n");
          }
          return;
        case REMOVED:
          sb.append("deleted: ").append(fieldPrefix).append(": ");
          if (expected().get() instanceof Message) {
            sb.append("\n").append(expected().get());
          } else {
            sb.append(valueString(subScopeId().get(), expected().get())).append("\n");
          }
          return;
        default:
          throw new AssertionError("Impossible: " + result());
      }
    }

    @Override
    final boolean isContentEmpty() {
      return false;
    }

    static SingularField ignored(String fieldName) {
      return newBuilder().setFieldName(fieldName).setResult(Result.IGNORED).build();
    }

    static Builder newBuilder() {
      return new AutoValue_DiffResult_SingularField.Builder();
    }

    /** Builder for {@link SingularField}. */
    @CanIgnoreReturnValue
    @AutoValue.Builder
    abstract static class Builder {
      abstract Builder setResult(Result result);

      abstract Builder setSubScopeId(SubScopeId subScopeId);

      abstract Builder setFieldName(String fieldName);

      abstract Builder setActual(Object actual);

      abstract Builder setExpected(Object expected);

      abstract Builder setBreakdown(DiffResult breakdown);

      abstract Builder setUnknownsBreakdown(UnknownFieldSetDiff unknownsBreakdown);

      abstract SingularField build();
    }
  }

  /**
   * Structural summary of the difference between two repeated fields.
   *
   * <p>This is only present if the user specified {@code ignoringRepeatedFieldOrder()}. Otherwise,
   * the repeated elements are compared as singular fields, and there are no 'move' semantics.
   */
  @AutoValue
  abstract static class RepeatedField extends RecursableDiffEntity.WithoutResultCode {

    /**
     * Structural summary of the difference between two elements in two corresponding repeated
     * fields, in the context of a {@link RepeatedField} diff.
     *
     * <p>The field indexes will only be present if the corresponding object is also present. If an
     * object is absent, the PairResult represents an extra/missing element in the repeated field.
     * If both are present but the indexes differ, it represents a 'move'.
     */
    @AutoValue
    abstract static class PairResult extends RecursableDiffEntity.WithResultCode {
      /** The {@link FieldDescriptor} describing the repeated field for this pair. */
      abstract FieldDescriptor fieldDescriptor();

      /** The index of the element in the {@code actual()} list that was matched. */
      abstract Optional<Integer> actualFieldIndex();

      /** The index of the element in the {@code expected()} list that was matched. */
      abstract Optional<Integer> expectedFieldIndex();

      /** The element in the {@code actual()} list that was matched. */
      abstract Optional<Object> actual();

      /** The element in the {@code expected()} list that was matched. */
      abstract Optional<Object> expected();

      /**
       * A detailed breakdown of the comparison between the messages. Present iff {@code actual()}
       * and {@code expected()} are {@link Message}s.
       */
      abstract Optional<DiffResult> breakdown();

      @Memoized
      @Override
      Iterable<? extends RecursableDiffEntity> childEntities() {
        return breakdown().asSet();
      }

      /** Returns true if actual() and expected() contain Message types. */
      @Memoized
      boolean isMessage() {
        return actual().orNull() instanceof Message || expected().orNull() instanceof Message;
      }

      private static String indexed(String fieldPrefix, Optional<Integer> fieldIndex) {
        String index = fieldIndex.isPresent() ? fieldIndex.get().toString() : "?";
        return fieldPrefix + "[" + index + "]";
      }

      @Override
      final void printContents(boolean includeMatches, String fieldPrefix, StringBuilder sb) {
        printContentsForRepeatedField(
            /* includeSelfAlways = */ false, includeMatches, fieldPrefix, sb);
      }

      // When printing results for a repeated field, we want to print matches even if
      // !includeMatches if there's a mismatch on the repeated field itself, but not recursively.
      // So we define a second printing method for use by the parent.
      final void printContentsForRepeatedField(
          boolean includeSelfAlways, boolean includeMatches, String fieldPrefix, StringBuilder sb) {
        if (!includeSelfAlways && !includeMatches && isMatched()) {
          return;
        }

        switch (result()) {
          case ADDED:
            sb.append("added: ").append(indexed(fieldPrefix, actualFieldIndex())).append(": ");
            if (isMessage()) {
              sb.append("\n").append(actual().get());
            } else {
              sb.append(valueString(fieldDescriptor(), actual().get())).append("\n");
            }
            return;
          case IGNORED:
            sb.append("ignored: ");
            if (actualFieldIndex().equals(expectedFieldIndex())) {
              sb.append(indexed(fieldPrefix, actualFieldIndex()));
            } else {
              sb.append(indexed(fieldPrefix, expectedFieldIndex()))
                  .append(" -> ")
                  .append(indexed(fieldPrefix, actualFieldIndex()));
            }

            // We output the message contents for ignored pair results, since it's likely not clear
            // from the index alone why they were ignored.
            sb.append(":");
            if (isMessage()) {
              sb.append("\n");
              printChildContents(includeMatches, indexed(fieldPrefix, actualFieldIndex()), sb);
            } else {
              sb.append(" ").append(valueString(fieldDescriptor(), actual().get())).append("\n");
            }
            return;
          case MATCHED:
            if (actualFieldIndex().get().equals(expectedFieldIndex().get())) {
              sb.append("matched: ").append(indexed(fieldPrefix, actualFieldIndex()));
            } else {
              sb.append("moved: ")
                  .append(indexed(fieldPrefix, expectedFieldIndex()))
                  .append(" -> ")
                  .append(indexed(fieldPrefix, actualFieldIndex()));
            }
            sb.append(":");
            if (isMessage()) {
              sb.append("\n");
              printChildContents(includeMatches, indexed(fieldPrefix, actualFieldIndex()), sb);
            } else {
              sb.append(" ").append(valueString(fieldDescriptor(), actual().get())).append("\n");
            }
            return;
          case MOVED_OUT_OF_ORDER:
            sb.append("out_of_order: ")
                .append(indexed(fieldPrefix, expectedFieldIndex()))
                .append(" -> ")
                .append(indexed(fieldPrefix, actualFieldIndex()));
            sb.append(":");
            if (isMessage()) {
              sb.append("\n");
              printChildContents(includeMatches, indexed(fieldPrefix, actualFieldIndex()), sb);
            } else {
              sb.append(" ").append(valueString(fieldDescriptor(), actual().get())).append("\n");
            }
            return;
          case MODIFIED:
            sb.append("modified: ");
            if (actualFieldIndex().get().equals(expectedFieldIndex().get())) {
              sb.append(indexed(fieldPrefix, actualFieldIndex()));
            } else {
              sb.append(indexed(fieldPrefix, expectedFieldIndex()))
                  .append(" -> ")
                  .append(indexed(fieldPrefix, actualFieldIndex()));
            }
            sb.append(":");
            if (isMessage()) {
              sb.append("\n");
              printChildContents(includeMatches, indexed(fieldPrefix, actualFieldIndex()), sb);
            } else {
              sb.append(" ")
                  .append(valueString(fieldDescriptor(), expected().get()))
                  .append(" -> ")
                  .append(valueString(fieldDescriptor(), actual().get()));
            }
            return;
          case REMOVED:
            sb.append("deleted: ").append(indexed(fieldPrefix, expectedFieldIndex())).append(": ");
            if (isMessage()) {
              sb.append("\n").append(expected().get());
            } else {
              sb.append(valueString(fieldDescriptor(), expected().get())).append("\n");
            }
            return;
        }
        throw new AssertionError("Impossible: " + result());
      }

      @Override
      final boolean isContentEmpty() {
        return false;
      }

      abstract Builder toBuilder();

      static Builder newBuilder() {
        return new AutoValue_DiffResult_RepeatedField_PairResult.Builder();
      }

      @CanIgnoreReturnValue
      @AutoValue.Builder
      abstract static class Builder {
        abstract Builder setResult(Result result);

        abstract Builder setFieldDescriptor(FieldDescriptor fieldDescriptor);

        abstract Builder setActualFieldIndex(int actualFieldIndex);

        abstract Builder setExpectedFieldIndex(int expectedFieldIndex);

        abstract Builder setActual(Object actual);

        abstract Builder setExpected(Object expected);

        abstract Builder setBreakdown(DiffResult breakdown);

        abstract PairResult build();
      }
    }

    /** The {@link FieldDescriptor} for this repeated field. */
    abstract FieldDescriptor fieldDescriptor();

    /** The elements under test. */
    abstract ImmutableList<Object> actual();

    /** The elements expected. */
    abstract ImmutableList<Object> expected();

    // TODO(user,peteg): Also provide a minimum-edit-distance pairing between unmatched elements,
    // and the diff report between them.

    /** Pairs of elements which were diffed against each other. */
    abstract ImmutableList<PairResult> pairResults();

    @Memoized
    @Override
    Iterable<? extends RecursableDiffEntity> childEntities() {
      return pairResults();
    }

    @Override
    final void printContents(boolean includeMatches, String fieldPrefix, StringBuilder sb) {
      fieldPrefix = newFieldPrefix(fieldPrefix, fieldDescriptor().getName());
      for (PairResult pairResult : pairResults()) {
        pairResult.printContentsForRepeatedField(
            /* includeSelfAlways = */ !isMatched(), includeMatches, fieldPrefix, sb);
      }
    }

    @Override
    final boolean isContentEmpty() {
      return pairResults().isEmpty();
    }

    static Builder newBuilder() {
      return new AutoValue_DiffResult_RepeatedField.Builder();
    }

    @CanIgnoreReturnValue
    @AutoValue.Builder
    abstract static class Builder {
      abstract Builder setFieldDescriptor(FieldDescriptor fieldDescriptor);

      abstract Builder setActual(Iterable<?> actual);

      abstract Builder setExpected(Iterable<?> expected);

      @ForOverride
      abstract ImmutableList.Builder<PairResult> pairResultsBuilder();

      final Builder addPairResult(PairResult pairResult) {
        pairResultsBuilder().add(pairResult);
        return this;
      }

      abstract RepeatedField build();
    }
  }

  /** Structural summary of the difference between two unknown field sets. */
  @AutoValue
  abstract static class UnknownFieldSetDiff extends RecursableDiffEntity.WithoutResultCode {
    /** The {@link UnknownFieldSet} being tested. */
    abstract Optional<UnknownFieldSet> actual();

    /** The {@link UnknownFieldSet} expected. */
    abstract Optional<UnknownFieldSet> expected();

    /**
     * A list of top-level singular field comparison results.
     *
     * <p>All unknown fields are treated as repeated and with {@code ignoringRepeatedFieldOrder()}
     * off, because we don't know their nature. If they're optional, only last element matters, but
     * if they're repeated, all elements matter.
     */
    abstract ImmutableListMultimap<Integer, SingularField> singularFields();

    @Memoized
    @Override
    Iterable<? extends RecursableDiffEntity> childEntities() {
      return singularFields().values();
    }

    @Override
    final void printContents(boolean includeMatches, String fieldPrefix, StringBuilder sb) {
      if (!includeMatches && isMatched()) {
        return;
      }

      for (int fieldNumber : singularFields().keySet()) {
        for (SingularField singularField : singularFields().get(fieldNumber)) {
          singularField.printContents(includeMatches, fieldPrefix, sb);
        }
      }
    }

    @Override
    final boolean isContentEmpty() {
      return singularFields().isEmpty();
    }

    static Builder newBuilder() {
      return new AutoValue_DiffResult_UnknownFieldSetDiff.Builder();
    }

    @CanIgnoreReturnValue
    @AutoValue.Builder
    abstract static class Builder {
      abstract Builder setActual(UnknownFieldSet actual);

      abstract Builder setExpected(UnknownFieldSet expected);

      @ForOverride
      abstract ImmutableListMultimap.Builder<Integer, SingularField> singularFieldsBuilder();

      final Builder addSingularField(int fieldNumber, SingularField singularField) {
        singularFieldsBuilder().put(fieldNumber, singularField);
        return this;
      }

      final Builder addAllSingularFields(int fieldNumber, Iterable<SingularField> singularFields) {
        singularFieldsBuilder().putAll(fieldNumber, singularFields);
        return this;
      }

      abstract UnknownFieldSetDiff build();
    }
  }

  /** The {@link Message} being tested. */
  abstract Message actual();

  /** The {@link Message} expected. */
  abstract Message expected();

  /** A list of top-level singular field comparison results grouped by field number. */
  abstract ImmutableListMultimap<Integer, SingularField> singularFields();

  /**
   * A list of top-level repeated field comparison results grouped by field number.
   *
   * <p>This is only populated if {@link FluentEqualityConfig#ignoreRepeatedFieldOrder()} is set.
   * Otherwise, repeated fields are compared strictly in index order, as singular fields.
   */
  abstract ImmutableListMultimap<Integer, RepeatedField> repeatedFields();

  /**
   * The result of comparing the message's {@link UnknownFieldSet}s. Not present if unknown fields
   * were not compared.
   */
  abstract Optional<UnknownFieldSetDiff> unknownFields();

  @Memoized
  @Override
  Iterable<? extends RecursableDiffEntity> childEntities() {
    // Assemble the diffs in field number order so it most closely matches the schema.
    ImmutableList.Builder<RecursableDiffEntity> builder =
        ImmutableList.builderWithExpectedSize(
            singularFields().size() + repeatedFields().size() + unknownFields().asSet().size());
    Set<Integer> fieldNumbers = Sets.union(singularFields().keySet(), repeatedFields().keySet());
    for (int fieldNumber : Ordering.natural().sortedCopy(fieldNumbers)) {
      builder.addAll(singularFields().get(fieldNumber));
      builder.addAll(repeatedFields().get(fieldNumber));
    }
    builder.addAll(unknownFields().asSet());
    return builder.build();
  }

  /** Prints the full {@link DiffResult} to a human-readable string, for use in test outputs. */
  final String printToString(boolean reportMismatchesOnly) {
    StringBuilder sb = new StringBuilder();

    if (!isMatched()) {
      sb.append("Differences were found:\n");
      printContents(/* includeMatches = */ false, /* fieldPrefix = */ "", sb);

      if (!reportMismatchesOnly && isAnyChildMatched()) {
        sb.append("\nFull diff report:\n");
        printContents(/* includeMatches = */ true, /* fieldPrefix = */ "", sb);
      }
    } else {
      sb.append("No differences were found.");
      if (!reportMismatchesOnly) {
        if (isAnyChildIgnored()) {
          sb.append("\nSome fields were ignored for comparison, however.\n");
        } else {
          sb.append("\nFull diff report:\n");
        }
        printContents(/* includeMatches = */ true, /* fieldPrefix = */ "", sb);
      }
    }

    return sb.toString();
  }

  @Override
  final void printContents(boolean includeMatches, String fieldPrefix, StringBuilder sb) {
    for (RecursableDiffEntity child : childEntities()) {
      child.printContents(includeMatches, fieldPrefix, sb);
    }
  }

  @Override
  final boolean isContentEmpty() {
    return Iterables.isEmpty(childEntities());
  }

  static Builder newBuilder() {
    return new AutoValue_DiffResult.Builder();
  }

  private static String newFieldPrefix(String rootFieldPrefix, String toAdd) {
    return rootFieldPrefix.isEmpty() ? toAdd : (rootFieldPrefix + "." + toAdd);
  }

  private static String valueString(SubScopeId subScopeId, Object o) {
    switch (subScopeId.kind()) {
      case FIELD_DESCRIPTOR:
        return valueString(subScopeId.fieldDescriptor(), o);
      case UNKNOWN_FIELD_DESCRIPTOR:
        return valueString(subScopeId.unknownFieldDescriptor(), o);
      case UNPACKED_ANY_VALUE_TYPE:
        return valueString(AnyUtils.valueFieldDescriptor(), o);
    }
    throw new AssertionError(subScopeId.kind());
  }

  private static String valueString(FieldDescriptor fieldDescriptor, Object o) {
    StringBuilder sb = new StringBuilder();
    try {
      TextFormat.printFieldValue(fieldDescriptor, o, sb);
      return sb.toString();
    } catch (IOException impossible) {
      throw new AssertionError(impossible);
    }
  }

  private static String valueString(UnknownFieldDescriptor unknownFieldDescriptor, Object o) {
    StringBuilder sb = new StringBuilder();
    try {
      TextFormat.printUnknownFieldValue(unknownFieldDescriptor.type().wireType(), o, sb);
      return sb.toString();
    } catch (IOException impossible) {
      throw new AssertionError(impossible);
    }
  }

  @CanIgnoreReturnValue
  @AutoValue.Builder
  abstract static class Builder {
    abstract Builder setActual(Message actual);

    abstract Builder setExpected(Message expected);

    @ForOverride
    abstract ImmutableListMultimap.Builder<Integer, SingularField> singularFieldsBuilder();

    final Builder addSingularField(int fieldNumber, SingularField singularField) {
      singularFieldsBuilder().put(fieldNumber, singularField);
      return this;
    }

    final Builder addAllSingularFields(int fieldNumber, Iterable<SingularField> singularFields) {
      singularFieldsBuilder().putAll(fieldNumber, singularFields);
      return this;
    }

    @ForOverride
    abstract ImmutableListMultimap.Builder<Integer, RepeatedField> repeatedFieldsBuilder();

    final Builder addRepeatedField(int fieldNumber, RepeatedField repeatedField) {
      repeatedFieldsBuilder().put(fieldNumber, repeatedField);
      return this;
    }

    abstract Builder setUnknownFields(UnknownFieldSetDiff unknownFields);

    abstract DiffResult build();
  }
}