Add support for SnakeYaml to parse timestamps correctly when timezone…

… is set or not (#5626)

* - Create a new SnakeYaml construct for timestamp to be able to handle timezones.
- Tests added.

* - Create a new SnakeYaml construct for timestamp to be able to handle timezones.
- Tests added.

* Update CustomConstructYamlTimeStamp to consistently return a given date as a String.

liquibase-standard/src/main/java/liquibase/parser/core/yaml/CustomConstructYamlTimestamp.java

@@ -0,0 +1,83 @@
+package liquibase.parser.core.yaml;
+
+import org.yaml.snakeyaml.constructor.SafeConstructor;
+import org.yaml.snakeyaml.error.YAMLException;
+import org.yaml.snakeyaml.nodes.Node;
+import org.yaml.snakeyaml.nodes.ScalarNode;
+
+import java.util.Calendar;
+import java.util.TimeZone;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class CustomConstructYamlTimestamp extends SafeConstructor.ConstructYamlTimestamp {
+    private final static Pattern TIMESTAMP_REGEXP = Pattern.compile(
+            "^([0-9][0-9][0-9][0-9])-([0-9][0-9]?)-([0-9][0-9]?)(?:(?:[Tt]|[ \t]+)([0-9][0-9]?):([0-9][0-9]):([0-9][0-9])(?:\\.([0-9]*))?(?:[ \t]*(?:Z|([-+][0-9][0-9]?)(?::([0-9][0-9])?)?))?)?$");
+    private final static Pattern YMD_REGEXP =
+            Pattern.compile("^([0-9][0-9][0-9][0-9])-([0-9][0-9]?)-([0-9][0-9]?)$");
+
+    private Calendar calendar;
+
+    @Override
+    public Object construct(Node node) {
+        ScalarNode scalar = (ScalarNode) node;
+        String nodeValue = scalar.getValue();
+        Matcher match = YMD_REGEXP.matcher(nodeValue);
+        if (match.matches()) {
+            String year_s = match.group(1);
+            String month_s = match.group(2);
+            String day_s = match.group(3);
+            calendar = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
+            calendar.clear();
+            calendar.set(Calendar.YEAR, Integer.parseInt(year_s));
+            // Java's months are zero-based...
+            calendar.set(Calendar.MONTH, Integer.parseInt(month_s) - 1); // x
+            calendar.set(Calendar.DAY_OF_MONTH, Integer.parseInt(day_s));
+            return calendar.getTime();
+        } else {
+            match = TIMESTAMP_REGEXP.matcher(nodeValue);
+            if (!match.matches()) {
+                throw new YAMLException("Unexpected timestamp: " + nodeValue);
+            }
+            String year_s = match.group(1);
+            String month_s = match.group(2);
+            String day_s = match.group(3);
+            String hour_s = match.group(4);
+            String min_s = match.group(5);
+            // seconds and milliseconds
+            String seconds = match.group(6);
+            String millis = match.group(7);
+            if (millis != null) {
+                seconds = seconds + "." + millis;
+            }
+            double fractions = Double.parseDouble(seconds);
+            int sec_s = (int) Math.round(Math.floor(fractions));
+            int usec = (int) Math.round((fractions - sec_s) * 1000);
+            // timezone
+            String timezoneh_s = match.group(8);
+            String timezonem_s = match.group(9);
+            TimeZone timeZone = null;
+            if (timezoneh_s != null) {
+                String time = timezonem_s != null ? ":" + timezonem_s : "00";
+                timeZone = TimeZone.getTimeZone("GMT" + timezoneh_s + time);
+                calendar = Calendar.getInstance(timeZone);
+                ;
+            } else {
+                calendar = Calendar.getInstance();
+            }
+            calendar.set(Calendar.YEAR, Integer.parseInt(year_s));
+            // Java's months are zero-based...
+            calendar.set(Calendar.MONTH, Integer.parseInt(month_s) - 1);
+            calendar.set(Calendar.DAY_OF_MONTH, Integer.parseInt(day_s));
+            calendar.set(Calendar.HOUR_OF_DAY, Integer.parseInt(hour_s));
+            calendar.set(Calendar.MINUTE, Integer.parseInt(min_s));
+            calendar.set(Calendar.SECOND, sec_s);
+            calendar.set(Calendar.MILLISECOND, usec);
+            if (timeZone == null) {
+                return new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(calendar.getTime());
+            } else {
+                return calendar.getTime().toString();
+            }
+        }
+    }
+}

liquibase-standard/src/main/java/liquibase/parser/core/yaml/YamlChangeLogParser.java

@@ -13,8 +13,10 @@
 import liquibase.resource.Resource;
 import liquibase.resource.ResourceAccessor;
 import liquibase.util.FileUtil;
+import org.yaml.snakeyaml.LoaderOptions;
 import org.yaml.snakeyaml.Yaml;
 import org.yaml.snakeyaml.constructor.SafeConstructor;
+import org.yaml.snakeyaml.nodes.Tag;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -25,7 +27,7 @@ public class YamlChangeLogParser extends YamlParser implements ChangeLogParser {
 
     @Override
     public DatabaseChangeLog parse(String physicalChangeLogLocation, ChangeLogParameters changeLogParameters, ResourceAccessor resourceAccessor) throws ChangeLogParseException {
-        Yaml yaml = new Yaml(new SafeConstructor(createLoaderOptions()));
+        Yaml yaml = new Yaml(new CustomSafeConstructor(createLoaderOptions()));
 
         try {
             Resource changelog = resourceAccessor.get(physicalChangeLogLocation);
@@ -183,4 +185,16 @@ protected void replaceParameters(Object obj, ChangeLogParameters changeLogParame
             }
         }
     }
+
+    static class CustomSafeConstructor extends SafeConstructor {
+        /**
+         * Create an instance
+         *
+         * @param loaderOptions - the configuration options
+         */
+        public CustomSafeConstructor(LoaderOptions loaderOptions) {
+            super(loaderOptions);
+            this.yamlConstructors.put(Tag.TIMESTAMP, new CustomConstructYamlTimestamp());
+        }
+    }
 }

liquibase-standard/src/test/groovy/liquibase/parser/core/yaml/CustomConstructYamlTimestampTest.groovy

@@ -0,0 +1,31 @@
+package liquibase.parser.core.yaml
+
+import org.yaml.snakeyaml.DumperOptions
+import org.yaml.snakeyaml.nodes.ScalarNode
+import org.yaml.snakeyaml.nodes.Tag
+import spock.lang.Specification
+
+class CustomConstructYamlTimestampTest extends Specification {
+    def "validate timestamp is parsed correctly without specifying a timezone"() {
+        given:
+         def node = new ScalarNode(new Tag("tag:yaml.org,2002:timestamp"), "2018-03-09 08:41:31.000", null, null, DumperOptions.ScalarStyle.createStyle(new Character('\'' as char)))
+        def customConstructYamlTimestamp = new CustomConstructYamlTimestamp()
+        when:
+        def returnedValue = customConstructYamlTimestamp.construct(node)
+
+        then:
+        returnedValue.toString() == "2018-03-09 08:41:31"
+    }
+
+    def "validate timestamp is parsed correctly specifying a timezone"() {
+        given:
+        TimeZone.setDefault(TimeZone.getTimeZone("PST"))
+        def node = new ScalarNode(new Tag("tag:yaml.org,2002:timestamp"), "2018-03-09 08:41:31.000+08:00", null, null, DumperOptions.ScalarStyle.createStyle(new Character('\'' as char)))
+        def customConstructYamlTimestamp = new CustomConstructYamlTimestamp()
+        when:
+        def returnedValue = customConstructYamlTimestamp.construct(node)
+
+        then:
+        returnedValue.toString() == "Thu Mar 08 16:41:31 PST 2018"
+    }
+}