Replace NOT operator with explicit false check (#67817)

We have an in-house rule to compare explicitly against `false` instead
of using the logical not operator (`!`). However, this hasn't
historically been enforced, meaning that there are many violations in
the source at present.

We now have a Checkstyle rule that can detect these cases, but before we
can turn it on, we need to fix the existing violations. This is being
done over a series of PRs, since there are a lot to fix.

buildSrc/src/main/groovy/org/elasticsearch/gradle/NoticeTask.groovy

@@ -124,7 +124,7 @@ class NoticeTask extends DefaultTask {
                     if (line.contains('*/')) {
                         inNotice = false
 
-                        if (!isPackageInfo) {
+                        if (isPackageInfo == false) {
                             break
                         }
                     } else if (inNotice) {

buildSrc/src/main/java/org/elasticsearch/gradle/ElasticsearchDistribution.java

@@ -105,7 +105,7 @@ public String toString() {
     private final Property<Boolean> failIfUnavailable;
     private final Configuration extracted;
     private Action<ElasticsearchDistribution> distributionFinalizer;
-    private boolean froozen = false;
+    private boolean frozen = false;
 
     ElasticsearchDistribution(
         String name,
@@ -207,10 +207,10 @@ public String toString() {
      * runs distribution finalizer logic.
      */
     public ElasticsearchDistribution maybeFreeze() {
-        if (!froozen) {
+        if (frozen == false) {
             finalizeValues();
             distributionFinalizer.execute(this);
-            froozen = true;
+            frozen = true;
         }
         return this;
     }

buildSrc/src/main/java/org/elasticsearch/gradle/internal/InternalDistributionDownloadPlugin.java

@@ -83,7 +83,7 @@ private void registerInternalDistributionResolutions(NamedDomainObjectContainer<
         resolutions.register("bwc", distributionResolution -> distributionResolution.setResolver((project, distribution) -> {
             BwcVersions.UnreleasedVersionInfo unreleasedInfo = bwcVersions.unreleasedInfo(Version.fromString(distribution.getVersion()));
             if (unreleasedInfo != null) {
-                if (!distribution.getBundledJdk()) {
+                if (distribution.getBundledJdk() == false) {
                     throw new GradleException(
                         "Configuring a snapshot bwc distribution ('"
                             + distribution.getName()

buildSrc/src/main/java/org/elasticsearch/gradle/internal/precommit/FilePermissionsTask.java

@@ -106,7 +106,7 @@ public void checkInvalidPermissions() throws IOException {
             .map(file -> "Source file is executable: " + file)
             .collect(Collectors.toList());
 
-        if (!failures.isEmpty()) {
+        if (failures.isEmpty() == false) {
             throw new GradleException("Found invalid file permissions:\n" + String.join("\n", failures));
         }
 

buildSrc/src/main/java/org/elasticsearch/gradle/testclusters/ElasticsearchNode.java

@@ -1267,7 +1267,7 @@ private void tweakJvmOptions(Path configFileRoot) {
             String content = new String(Files.readAllBytes(jvmOptions));
             Map<String, String> expansions = jvmOptionExpansions();
             for (String origin : expansions.keySet()) {
-                if (!content.contains(origin)) {
+                if (content.contains(origin) == false) {
                     throw new IOException("template property " + origin + " not found in template.");
                 }
                 content = content.replace(origin, expansions.get(origin));

buildSrc/src/main/java/org/elasticsearch/gradle/util/FileUtils.java

@@ -39,13 +39,13 @@ public static void mkdirs(File dir) {
             return;
         }
 
-        if (dir.exists() && !dir.isDirectory()) {
+        if (dir.exists() && dir.isDirectory() == false) {
             throw new UncheckedIOException(String.format("Cannot create directory '%s' as it already exists, but is not a directory", dir));
         }
 
         List<File> toCreate = new LinkedList<File>();
         File parent = dir.getParentFile();
-        while (!parent.exists()) {
+        while (parent.exists() == false) {
             toCreate.add(parent);
             parent = parent.getParentFile();
         }
@@ -55,7 +55,7 @@ public static void mkdirs(File dir) {
                 continue;
             }
             File parentDirToCreateParent = parentDirToCreate.getParentFile();
-            if (!parentDirToCreateParent.isDirectory()) {
+            if (parentDirToCreateParent.isDirectory() == false) {
                 throw new UncheckedIOException(
                     String.format(
                         "Cannot create parent directory '%s' when creating directory '%s' as '%s' is not a directory",
@@ -65,13 +65,13 @@ public static void mkdirs(File dir) {
                     )
                 );
             }
-            if (!parentDirToCreate.mkdir() && !parentDirToCreate.isDirectory()) {
+            if (parentDirToCreate.mkdir() == false && parentDirToCreate.isDirectory() == false) {
                 throw new UncheckedIOException(
                     String.format("Failed to create parent directory '%s' when creating directory '%s'", parentDirToCreate, dir)
                 );
             }
         }
-        if (!dir.mkdir() && !dir.isDirectory()) {
+        if (dir.mkdir() == false && dir.isDirectory() == false) {
             throw new UncheckedIOException(String.format("Failed to create directory '%s'", dir));
         }
     }

buildSrc/src/main/resources/checkstyle_ide_fragment.xml

@@ -15,7 +15,7 @@
         <property name="tokens" value="EXPR"/>
         <property name="limitedTokens" value="LNOT"/>
         <property name="maximumNumber" value="0"/>
-        <property name="maximumDepth" value="1"/>
+        <property name="maximumDepth" value="2"/>
         <message
             key="descendant.token.max"
             value="Do not negate boolean expressions with '!', but check explicitly with '== false' as it is more explicit"/>

client/benchmark/src/main/java/org/elasticsearch/client/benchmark/metrics/MetricsCalculator.java

@@ -37,7 +37,7 @@ private static Map<String, List<Sample>> groupByOperation(Collection<Sample> sam
         Map<String, List<Sample>> samplesPerOperation = new HashMap<>();
 
         for (Sample sample : samples) {
-            if (!samplesPerOperation.containsKey(sample.getOperation())) {
+            if (samplesPerOperation.containsKey(sample.getOperation()) == false) {
                 samplesPerOperation.put(sample.getOperation(), new ArrayList<>());
             }
             samplesPerOperation.get(sample.getOperation()).add(sample);

client/rest-high-level/src/main/java/org/elasticsearch/client/IngestRequestConverters.java

@@ -78,7 +78,7 @@ static Request deletePipeline(DeletePipelineRequest deletePipelineRequest) {
 
     static Request simulatePipeline(SimulatePipelineRequest simulatePipelineRequest) throws IOException {
         RequestConverters.EndpointBuilder builder = new RequestConverters.EndpointBuilder().addPathPartAsIs("_ingest/pipeline");
-        if (simulatePipelineRequest.getId() != null && !simulatePipelineRequest.getId().isEmpty()) {
+        if (simulatePipelineRequest.getId() != null && simulatePipelineRequest.getId().isEmpty() == false) {
             builder.addPathPart(simulatePipelineRequest.getId());
         }
         builder.addPathPartAsIs("_simulate");

client/rest-high-level/src/main/java/org/elasticsearch/client/ccr/GetAutoFollowPatternResponse.java

@@ -158,7 +158,7 @@ public String getFollowIndexNamePattern() {
         public boolean equals(Object o) {
             if (this == o) return true;
             if (o == null || getClass() != o.getClass()) return false;
-            if (!super.equals(o)) return false;
+            if (super.equals(o) == false) return false;
             Pattern pattern = (Pattern) o;
             return Objects.equals(remoteCluster, pattern.remoteCluster) &&
                 Objects.equals(leaderIndexPatterns, pattern.leaderIndexPatterns) &&

client/rest-high-level/src/main/java/org/elasticsearch/client/ccr/PutAutoFollowPatternRequest.java

@@ -81,7 +81,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
-        if (!super.equals(o)) return false;
+        if (super.equals(o) == false) return false;
         PutAutoFollowPatternRequest that = (PutAutoFollowPatternRequest) o;
         return Objects.equals(name, that.name) &&
             Objects.equals(remoteCluster, that.remoteCluster) &&

client/rest-high-level/src/main/java/org/elasticsearch/client/ccr/PutFollowRequest.java

@@ -79,7 +79,7 @@ public ActiveShardCount waitForActiveShards() {
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
-        if (!super.equals(o)) return false;
+        if (super.equals(o) == false) return false;
         PutFollowRequest that = (PutFollowRequest) o;
         return Objects.equals(waitForActiveShards, that.waitForActiveShards) &&
             Objects.equals(remoteCluster, that.remoteCluster) &&

client/rest-high-level/src/main/java/org/elasticsearch/client/ccr/ResumeFollowRequest.java

@@ -50,7 +50,7 @@ public String getFollowerIndex() {
     public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;
-        if (!super.equals(o)) return false;
+        if (super.equals(o) == false) return false;
         ResumeFollowRequest that = (ResumeFollowRequest) o;
         return Objects.equals(followerIndex, that.followerIndex);
     }

client/rest-high-level/src/main/java/org/elasticsearch/client/core/MultiTermVectorsResponse.java

@@ -64,7 +64,7 @@ public List<TermVectorsResponse> getTermVectorsResponses() {
     @Override
     public boolean equals(Object obj) {
         if (this == obj) return true;
-        if (!(obj instanceof MultiTermVectorsResponse)) return false;
+        if ((obj instanceof MultiTermVectorsResponse) == false) return false;
         MultiTermVectorsResponse other = (MultiTermVectorsResponse) obj;
         return Objects.equals(responses, other.responses);
     }

client/rest-high-level/src/main/java/org/elasticsearch/client/core/TermVectorsResponse.java

@@ -23,14 +23,15 @@
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.xcontent.ConstructingObjectParser;
 import org.elasticsearch.common.xcontent.XContentParser;
-import static org.elasticsearch.common.xcontent.ConstructingObjectParser.constructorArg;
-import static org.elasticsearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
 
 import java.util.Collections;
-import java.util.List;
 import java.util.Comparator;
+import java.util.List;
 import java.util.Objects;
 
+import static org.elasticsearch.common.xcontent.ConstructingObjectParser.constructorArg;
+import static org.elasticsearch.common.xcontent.ConstructingObjectParser.optionalConstructorArg;
+
 public class TermVectorsResponse {
     private final String index;
     private final String type;
@@ -142,7 +143,7 @@ public List<TermVector> getTermVectorsList(){
     @Override
     public boolean equals(Object obj) {
         if (this == obj) return true;
-        if (!(obj instanceof TermVectorsResponse)) return false;
+        if ((obj instanceof TermVectorsResponse) == false) return false;
         TermVectorsResponse other = (TermVectorsResponse) obj;
         return index.equals(other.index)
             && type.equals(other.type)
@@ -219,7 +220,7 @@ public FieldStatistics getFieldStatistics() {
         @Override
         public boolean equals(Object obj) {
             if (this == obj) return true;
-            if (!(obj instanceof TermVector)) return false;
+            if ((obj instanceof TermVector) == false) return false;
             TermVector other = (TermVector) obj;
             return fieldName.equals(other.fieldName)
                 && Objects.equals(fieldStatistics, other.fieldStatistics)
@@ -283,7 +284,7 @@ public long getSumTotalTermFreq() {
             @Override
             public boolean equals(Object obj) {
                 if (this == obj) return true;
-                if (!(obj instanceof FieldStatistics)) return false;
+                if ((obj instanceof FieldStatistics) == false) return false;
                 FieldStatistics other = (FieldStatistics) obj;
                 return docCount == other.docCount
                     && sumDocFreq == other.sumDocFreq
@@ -390,7 +391,7 @@ public List<Token> getTokens() {
             @Override
             public boolean equals(Object obj) {
                 if (this == obj) return true;
-                if (!(obj instanceof Term)) return false;
+                if ((obj instanceof Term) == false) return false;
                 Term other = (Term) obj;
                 return term.equals(other.term)
                     && termFreq == other.termFreq
@@ -472,7 +473,7 @@ public String getPayload() {
             @Override
             public boolean equals(Object obj) {
                 if (this == obj) return true;
-                if (!(obj instanceof Token)) return false;
+                if ((obj instanceof Token) == false) return false;
                 Token other = (Token) obj;
                 return Objects.equals(startOffset, other.startOffset)
                     && Objects.equals(endOffset,other.endOffset)

client/rest-high-level/src/main/java/org/elasticsearch/client/graph/Connection.java

@@ -34,7 +34,7 @@
 import static org.elasticsearch.common.xcontent.ConstructingObjectParser.constructorArg;
 
 /**
- * A Connection links exactly two {@link Vertex} objects. The basis of a 
+ * A Connection links exactly two {@link Vertex} objects. The basis of a
  * connection is one or more documents have been found that contain
  * this pair of terms and the strength of the connection is recorded
  * as a weight.
@@ -75,13 +75,13 @@ public double getWeight() {
     }
 
     /**
-     * @return the number of documents in the sampled set that contained this 
+     * @return the number of documents in the sampled set that contained this
      * pair of {@link Vertex} objects.
      */
     public long getDocCount() {
         return docCount;
     }
-    
+
     @Override
     public boolean equals(Object obj) {
         if (this == obj)
@@ -107,7 +107,7 @@ public int hashCode() {
     private static final ParseField TARGET = new ParseField("target");
     private static final ParseField WEIGHT = new ParseField("weight");
     private static final ParseField DOC_COUNT = new ParseField("doc_count");
-    
+
 
     void toXContent(XContentBuilder builder, Params params, ObjectIntHashMap<Vertex> vertexNumbers) throws IOException {
         builder.field(SOURCE.getPreferredName(), vertexNumbers.get(from));
@@ -131,10 +131,10 @@ static class UnresolvedConnection {
             this.weight = weight;
             this.docCount = docCount;
         }
-        public Connection resolve(List<Vertex> vertices) {            
+        public Connection resolve(List<Vertex> vertices) {
             return new Connection(vertices.get(fromIndex), vertices.get(toIndex), weight, docCount);
         }
-        
+
         private static final ConstructingObjectParser<UnresolvedConnection, Void> PARSER = new ConstructingObjectParser<>(
                 "ConnectionParser", true,
                 args -> {
@@ -150,13 +150,13 @@ public Connection resolve(List<Vertex> vertices) {
             PARSER.declareInt(constructorArg(), TARGET);
             PARSER.declareDouble(constructorArg(), WEIGHT);
             PARSER.declareLong(constructorArg(), DOC_COUNT);
-        }        
+        }
         static UnresolvedConnection fromXContent(XContentParser parser) throws IOException {
             return PARSER.apply(parser, null);
-        }         
+        }
     }
-       
-    
+
+
     /**
      * An identifier (implements hashcode and equals) that represents a
      * unique key for a {@link Connection}
@@ -179,9 +179,9 @@ public boolean equals(Object o) {
 
             ConnectionId vertexId = (ConnectionId) o;
 
-            if (source != null ? !source.equals(vertexId.source) : vertexId.source != null)
+            if (source != null ? source.equals(vertexId.source) == false : vertexId.source != null)
                 return false;
-            if (target != null ? !target.equals(vertexId.target) : vertexId.target != null)
+            if (target != null ? target.equals(vertexId.target) == false : vertexId.target != null)
                 return false;
 
             return true;
@@ -206,5 +206,5 @@ public VertexId getTarget() {
         public String toString() {
             return getSource() + "->" + getTarget();
         }
-    }    
+    }
 }