Safely call snakeyaml methods that have been changed in last versions. (

#3904)

* Safely call snakeyaml methods that have been changed in last versions.

liquibase-core/src/main/java/liquibase/parser/core/yaml/YamlParser.java

@@ -14,7 +14,7 @@ public abstract class YamlParser implements LiquibaseParser {
     public static LoaderOptions createLoaderOptions() {
         LoaderOptions options = new LoaderOptions();
         SnakeYamlUtil.setCodePointLimitSafely(options, Integer.MAX_VALUE);
-        options.setProcessComments(false);
+        SnakeYamlUtil.setProcessCommentsSafely(options, false);
         options.setAllowDuplicateKeys(false);
         options.setAllowRecursiveKeys(false);
         return options;

liquibase-core/src/main/java/liquibase/util/SnakeYamlUtil.java

@@ -3,25 +3,49 @@
 import liquibase.Scope;
 import org.yaml.snakeyaml.LoaderOptions;
 
+/**
+ * This class provides methods that are necessary because older (< 1.32) versions of SnakeYaml do not have
+ * those methods. Thus, if someone is using an older version of SnakeYaml, we do not want to interrupt Liquibase
+ * execution with an exception anymore.
+ */
 public class SnakeYamlUtil {
+
+    private static boolean showErrorMessage = true;
+
     private SnakeYamlUtil() {
 
     }
 
     /**
-     * Safely set the code point limit when configuring a new SnakeYaml instance. This method is necessary because
-     * older versions of SnakeYaml do not have the ability to set a code point limit. Thus, if someone is using an older
-     * version of SnakeYaml, we do not want to interrupt Liquibase execution with an exception.
+     * Safely set the code point limit when configuring a new SnakeYaml instance.
      */
     public static void setCodePointLimitSafely(LoaderOptions loaderOptions, int codePointLimit) {
+        safelyCallNewSnakeYamlMethod(() -> loaderOptions.setCodePointLimit(codePointLimit));
+    }
+
+    /**
+     * Safely set configuration to process comments when configuring a new SnakeYaml instance. This method
+     * had the return type changed.
+     */
+    public static void setProcessCommentsSafely(LoaderOptions loaderOptions, boolean enable) {
+        safelyCallNewSnakeYamlMethod(() -> loaderOptions.setProcessComments(enable));
+    }
+
+    /**
+     * Helper method to make sure that we display the error message only once.
+     */
+    private static void safelyCallNewSnakeYamlMethod(Runnable code) {
         try {
-            loaderOptions.setCodePointLimit(codePointLimit);
-        } catch (NoSuchMethodError e) {
-            Scope.getCurrentScope().getLog(SnakeYamlUtil.class).warning(
-                    "Failed to set code point limit for SnakeYaml, because the version of SnakeYaml being used is too old. " +
-                            "Consider upgrading to a SnakeYaml version equal to or newer than 1.32, by downloading and " +
-                            "installing a newer version of Liquibase (which includes a newer version of SnakeYaml). " +
-                            "Loading particularly large JSON and YAML documents (like snapshots) in Liquibase may fail if SnakeYaml is not upgraded.", e);
+            code.run();
+        } catch (NoSuchMethodError | BootstrapMethodError e) {
+            if (showErrorMessage) {
+                showErrorMessage = false;
+                Scope.getCurrentScope().getLog(SnakeYamlUtil.class).warning(
+                        "Failed to perform a method call for SnakeYaml because the version of SnakeYaml being used is too old. " +
+                                "Consider upgrading to a SnakeYaml version equal to or newer than 1.32, by downloading and " +
+                                "installing a newer version of Liquibase (which includes a newer version of SnakeYaml). " +
+                                "Loading particularly large JSON and YAML documents (like snapshots) in Liquibase may fail if SnakeYaml is not upgraded.", e);
+            }
         }
     }
 }