SONARJAVA-4606 New rule: use String.isEmpty() instead of String.length() == 0

.cirrus.yml

@@ -148,7 +148,7 @@
       orchestrator_LATEST_RELEASE_cache:
         <<: *ORCHESTRATOR_CACHE_ELEMENTS_DEFINITION
     - env:
-        SQ_VERSION: DEV
+        SQ_VERSION: DEV[10.8]
       orchestrator_DEV_cache:
         <<: *ORCHESTRATOR_CACHE_ELEMENTS_DEFINITION
 
@@ -269,7 +269,7 @@
     actual_artifacts:
       path: "${CIRRUS_WORKING_DIR}/its/autoscan/target/actual/**/*"
 
 promote_task:
   depends_on:
     - build
     - test_analyze

its/autoscan/src/test/resources/autoscan/diffs/diff_S7158.json

@@ -0,0 +1,6 @@
+{
+  "ruleKey": "S7158",
+  "hasTruePositives": true,
+  "falseNegatives": 0,
+  "falsePositives": 0
+}

its/ruling/src/test/resources/commons-beanutils/java-S7158.json

@@ -0,0 +1,46 @@
+{
+"commons-beanutils:commons-beanutils:src/main/java/org/apache/commons/beanutils2/BeanPropertyValueChangeClosure.java": [
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+],
+"commons-beanutils:commons-beanutils:src/main/java/org/apache/commons/beanutils2/BeanPropertyValueEqualsPredicate.java": [
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+],
+"commons-beanutils:commons-beanutils:src/main/java/org/apache/commons/beanutils2/BeanToPropertyValueTransformer.java": [
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+],
+"commons-beanutils:commons-beanutils:src/main/java/org/apache/commons/beanutils2/JDBCDynaClass.java": [
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+"commons-beanutils:commons-beanutils:src/main/java/org/apache/commons/beanutils2/MappedPropertyDescriptor.java": [
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+],
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+],
+"commons-beanutils:commons-beanutils:src/main/java/org/apache/commons/beanutils2/converters/CharacterConverter.java": [
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+],
+"commons-beanutils:commons-beanutils:src/main/java/org/apache/commons/beanutils2/converters/DateTimeConverter.java": [
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+],
+"commons-beanutils:commons-beanutils:src/main/java/org/apache/commons/beanutils2/converters/NumberConverter.java": [
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+]
+}

its/ruling/src/test/resources/eclipse-jetty-similar-to-main/java-S7158.json

@@ -0,0 +1,72 @@
+{
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+"org.eclipse.jetty:jetty-project:jetty-http/src/main/java/org/eclipse/jetty/http/pathmap/ServletPathSpec.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/Cookies.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/CustomRequestLog.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/PushBuilderImpl.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/RequestLogWriter.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/ResourceService.java": [
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+388
+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/Response.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/handler/ContextHandler.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/handler/jmx/AbstractHandlerMBean.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/session/DefaultSessionIdManager.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/test/java/org/eclipse/jetty/server/ConnectorTimeoutTest.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/test/java/org/eclipse/jetty/server/HttpConnectionTest.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/test/java/org/eclipse/jetty/server/HttpServerTestBase.java": [
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+1652,
+1667
+]
+}

its/ruling/src/test/resources/eclipse-jetty/java-S7158.json

@@ -0,0 +1,161 @@
+{
+"org.eclipse.jetty:jetty-project:jetty-http/src/main/java/org/eclipse/jetty/http/HttpCookie.java": [
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+298,
+315,
+317,
+382,
+396,
+400,
+508
+],
+"org.eclipse.jetty:jetty-project:jetty-http/src/main/java/org/eclipse/jetty/http/pathmap/PathMappings.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-http/src/main/java/org/eclipse/jetty/http/pathmap/ServletPathSpec.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-io/src/main/java/org/eclipse/jetty/io/AbstractEndPoint.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/Cookies.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/CustomRequestLog.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/PushBuilderImpl.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/RequestLogWriter.java": [
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+],
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/Response.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/handler/ContextHandler.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/main/java/org/eclipse/jetty/server/handler/jmx/AbstractHandlerMBean.java": [
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+],
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+"org.eclipse.jetty:jetty-project:jetty-server/src/test/java/org/eclipse/jetty/server/ConnectorTimeoutTest.java": [
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+"org.eclipse.jetty:jetty-project:jetty-server/src/test/java/org/eclipse/jetty/server/DumpHandler.java": [
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+],
+"org.eclipse.jetty:jetty-project:jetty-server/src/test/java/org/eclipse/jetty/server/ssl/SSLCloseTest.java": [
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+}

its/ruling/src/test/resources/guava/java-S7158.json

@@ -0,0 +1,28 @@
+{
+"com.google.guava:guava:src/com/google/common/base/Splitter.java": [
+176
+],
+"com.google.guava:guava:src/com/google/common/base/Strings.java": [
+78
+],
+"com.google.guava:guava:src/com/google/common/io/Files.java": [
+730
+],
+"com.google.guava:guava:src/com/google/common/net/InetAddresses.java": [
+233,
+247,
+250
+],
+"com.google.guava:guava:src/com/google/common/net/InternetDomainName.java": [
+259
+],
+"com.google.guava:guava:src/com/google/common/primitives/ParseRequest.java": [
+36
+],
+"com.google.guava:guava:src/com/google/common/primitives/UnsignedLongs.java": [
+304
+],
+"com.google.guava:guava:src/com/google/thirdparty/publicsuffix/TrieParser.java": [
+85
+]
+}

its/ruling/src/test/resources/sonar-server/java-S7158.json

@@ -0,0 +1,5 @@
+{
+"org.sonarsource.sonarqube:sonar-server:src/main/java/org/sonar/server/user/UserUpdater.java": [
+325
+]
+}

java-checks-test-sources/default/src/main/java/checks/StringIsEmptyCheckSample.java

@@ -0,0 +1,54 @@
+package checks;
+
+public class StringIsEmptyCheckSample {
+  public boolean sample(String s, String t) {
+    boolean b;
+
+    // test `length() == 0` and equivalent code
+    b = s.length() == 0; // Noncompliant
+    b = s.length() <= 0; // Noncompliant
+    b = s.length() < 1; // Noncompliant
+
+    // test `length() != 0` and equivalent code
+    b = s.length() != 0; // Noncompliant
+    b = s.length() > 0; // Noncompliant
+    b = s.length() >= 1; // Noncompliant
+
+    // reversed order
+    b = 0 == s.length(); // Noncompliant
+    b = 0 >= s.length(); // Noncompliant
+    b = 1 > s.length(); // Noncompliant
+    b = 0 != s.length(); // Noncompliant
+    b = 0 < s.length(); // Noncompliant
+    b = 1 <= s.length(); // Noncompliant
+
+    // extra parentheses
+    b = (s.length()) == 0; // Noncompliant
+
+    // chained method calls
+    b = s.toUpperCase().length() == 0; // Noncompliant
+
+    // problem in a nested expression
+    b = "abc".equals(s) || s.length() == 0; // Noncompliant
+
+    b = s.length() == 1;
+    b = s.length() > 3;
+    b = s.length() <= 10;
+    b = 2 < s.length();
+
+    b = s.trim().length() >= 8;
+
+    b = s.length() == t.length();
+
+    b = s.isEmpty();
+    b = !s.isEmpty();
+
+    b = 1 < 0;
+
+    // StringBuilder does not have `isEmpty()`
+    StringBuilder stringBuilder = new StringBuilder();
+    b = stringBuilder.length() == 0;
+
+    return b;
+  }
+}