Fix parameters handling when using an incrementer

This commit changes the way job parameters are handled
when the job defines an incrementer.

Before this commit, additional parameters were overriding
the ones of the previous execution. This commit changes that
by ignoring additional parameters and warning the user about
this incorrect usage of the framework.

Resolves #4910

Author: fmbenhassine

spring-batch-core/src/main/java/org/springframework/batch/core/launch/JobOperator.java

@@ -73,7 +73,9 @@ default Long start(String jobName, Properties parameters)
 	}
 
 	/**
-	 * Start a new instance of a job with the specified parameters.
+	 * Start a new instance of a job with the specified parameters. If the job defines a
+	 * {@link JobParametersIncrementer}, then the incrementer will be used to calculate
+	 * the next parameters in the sequence and the provided parameters will be ignored.
 	 * @param job the {@link Job} to start
 	 * @param jobParameters the {@link JobParameters} to start the job with
 	 * @return the {@link JobExecution} that was started
@@ -90,7 +92,7 @@ default Long start(String jobName, Properties parameters)
 	default JobExecution start(Job job, JobParameters jobParameters)
 			throws NoSuchJobException, JobInstanceAlreadyCompleteException, JobExecutionAlreadyRunningException,
 			JobRestartException, JobParametersInvalidException {
-		return run(job, jobParameters);
+		throw new UnsupportedOperationException();
 	}
 
 	/**
@@ -179,20 +181,15 @@ Long startNextInstance(String jobName) throws NoSuchJobException, JobParametersN
 	 * method (or a similar one) at the same time.
 	 * @param job the job to launch
 	 * @return the {@link JobExecution} created when the job is launched
-	 * @throws NoSuchJobException if there is no such job definition available
-	 * @throws JobParametersNotFoundException if the parameters cannot be found
-	 * @throws JobParametersInvalidException thrown if some of the job parameters are
-	 * invalid.
 	 * @throws UnexpectedJobExecutionException if an unexpected condition arises
 	 * @throws JobRestartException thrown if a job is restarted illegally.
 	 * @throws JobExecutionAlreadyRunningException thrown if attempting to restart a job
 	 * that is already executing.
 	 * @throws JobInstanceAlreadyCompleteException thrown if attempting to restart a
 	 * completed job.
 	 */
-	JobExecution startNextInstance(Job job) throws NoSuchJobException, JobParametersNotFoundException,
-			JobRestartException, JobExecutionAlreadyRunningException, JobInstanceAlreadyCompleteException,
-			UnexpectedJobExecutionException, JobParametersInvalidException;
+	JobExecution startNextInstance(Job job) throws JobRestartException, JobExecutionAlreadyRunningException,
+			JobInstanceAlreadyCompleteException, UnexpectedJobExecutionException;
 
 	/**
 	 * Send a stop signal to the {@link JobExecution} with the supplied id. The signal is

spring-batch-core/src/main/java/org/springframework/batch/core/launch/support/SimpleJobOperator.java

@@ -165,6 +165,39 @@ public Long start(String jobName, Properties parameters)
 
 	}
 
+	/**
+	 * Start a new instance of a job with the specified parameters. If the job defines a
+	 * {@link JobParametersIncrementer}, then the incrementer will be used to calculate
+	 * the next parameters in the sequence and the provided parameters will be ignored.
+	 * @param job the {@link Job} to start
+	 * @param jobParameters the {@link JobParameters} to start the job with
+	 * @return the {@link JobExecution} that was started
+	 * @throws NoSuchJobException if the given {@link Job} is not registered
+	 * @throws JobParametersInvalidException thrown if any of the job parameters are
+	 * @throws JobExecutionAlreadyRunningException if the JobInstance identified by the
+	 * properties already has an execution running. invalid.
+	 * @throws JobRestartException if the execution would be a re-start, but a re-start is
+	 * either not allowed or not needed.
+	 * @throws JobInstanceAlreadyCompleteException if the job has been run before with the
+	 * same parameters and completed successfully
+	 * @throws IllegalArgumentException if the job or job parameters are null.
+	 */
+	public JobExecution start(Job job, JobParameters jobParameters)
+			throws NoSuchJobException, JobInstanceAlreadyCompleteException, JobExecutionAlreadyRunningException,
+			JobRestartException, JobParametersInvalidException {
+		Assert.notNull(job, "The Job must not be null.");
+		Assert.notNull(jobParameters, "The JobParameters must not be null.");
+		if (job.getJobParametersIncrementer() != null) {
+			if (logger.isWarnEnabled()) {
+				logger.warn(String.format(
+						"Attempting to launch the job %s which defines an incrementer with additional parameters={%s}. Those parameters will be ignored.",
+						job.getName(), jobParameters));
+			}
+			startNextInstance(job);
+		}
+		return run(job, jobParameters);
+	}
+
 	@SuppressWarnings("removal")
 	@Override
 	@Deprecated(since = "6.0", forRemoval = true)
@@ -228,8 +261,7 @@ public Long startNextInstance(String jobName)
 	}
 
 	@Override
-	public JobExecution startNextInstance(Job job)
-			throws NoSuchJobException, UnexpectedJobExecutionException, JobParametersInvalidException {
+	public JobExecution startNextInstance(Job job) throws UnexpectedJobExecutionException {
 		Assert.notNull(job, "Job must not be null");
 		Assert.notNull(job.getJobParametersIncrementer(),
 				"No job parameters incrementer found for job=" + job.getName());
@@ -271,6 +303,9 @@ public JobExecution startNextInstance(Job job)
 					String.format(ILLEGAL_STATE_MSG, "job instance already complete", job.getName(), nextParameters),
 					e);
 		}
+		catch (JobParametersInvalidException e) {
+			throw new UnexpectedJobExecutionException("Invalid job parameters " + nextParameters, e);
+		}
 
 	}
 

spring-batch-core/src/test/java/org/springframework/batch/core/launch/support/TaskExecutorJobOperatorTests.java

@@ -182,6 +182,12 @@ void testStartNewInstanceAlreadyExists() {
 		assertThrows(JobInstanceAlreadyExistsException.class, () -> jobOperator.start("foo", properties));
 	}
 
+	@Test
+	void testStartWithIncrementer() throws Exception {
+		jobOperator.start(job, new JobParameters());
+		verify(jobRepository).getLastJobInstance("foo");
+	}
+
 	@Test
 	void testResumeSunnyDay() throws Exception {
 		jobParameters = new JobParameters();