DataSource url property is ignored when there is no connection pool

[nosan]

see gh-19192

Btw, I found an issue in DataSourceBuilder, the builder does not support SimpleDriverDataSource without alias aliases.addAliases("driver-class-name", "driver-class")

Here is a test to reproduce:

	@Test
	void simpleDriverDataSource() {
		this.dataSource = DataSourceBuilder.create().url("jdbc:h2:test").type(SimpleDriverDataSource.class).build();
		assertThat(this.dataSource).isInstanceOf(SimpleDriverDataSource.class);
		assertThat(this.dataSource).extracting("driver").isNotNull();
	}

`

UPDATE

My first approach was incorrect. Sorry for the inconvenience.

[snicoll]

Thanks for the PR @nosan.

I found an issue in DataSourceBuilder, the builder does not support SimpleDriverDataSource

It's not meant to at the moment. The supported connection pools are commons-dbcp2, tomcat and hikari (default).

[nosan]

Thanks for the feedback, @snicoll

It's not meant to at the moment. The supported connection pools are commons-dbcp2, tomcat and hikari (default).

Yes, I saw that when I was working on this PR.
Consider this test in DataSourceAutoConfigurationTests:

@Test
void explicitTypeSupportedDataSource() {
	this.contextRunner
			.withPropertyValues("spring.datasource.driverClassName:org.hsqldb.jdbcDriver",
					"spring.datasource.url:jdbc:hsqldb:mem:testdb",
					"spring.datasource.type:" + SimpleDriverDataSource.class.getName())
			.run(this::containsOnlySimpleDriverDataSource);
}

Actually, this test just checks that SimpleDriverDataSource will be created, and actually, it will, but still, if you try to getConnection from this DataSource you will get an exception:

java.lang.IllegalArgumentException: Driver must not be null

	at org.springframework.util.Assert.notNull(Assert.java:198)
	at org.springframework.jdbc.datasource.SimpleDriverDataSource.getConnectionFromDriver(SimpleDriverDataSource.java:139)
	at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnectionFromDriver(AbstractDriverBasedDataSource.java:205)
	at org.springframework.jdbc.datasource.AbstractDriverBasedDataSource.getConnection(AbstractDriverBasedDataSource.java:169)
	at org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfigurationTests.containsOnlySimpleDriverDataSource(DataSourceAutoConfigurationTests.java:172)

This happens because DataSourceBuilder does not add alias:

aliases.addAliases("driver-class-name", "driver-class");

P.S. I think you are right and this is not related to the initial issue.

[wilkinsona]

We should rename this when merging. Something like ExplicitDataSourceTypeOrUrlCondition.

[wilkinsona]

If possible, when merging, we should replace this comment with a descriptive test method name

[snicoll]

I was looking at this PR and I am not keen to bring support for SimpleDriverDataSource back in 2.1.x. I'd rather let it fail which is what would happen if there wasn't an embedded driver on the claspath in the first place.

With a polish that doesn't bring support for SimpleDriverDataSource it would fail as follow (rather than creating an embedded database if one is available):

Caused by: java.lang.IllegalStateException: No supported DataSource type found
 	at org.springframework.boot.jdbc.DataSourceBuilder.getType(DataSourceBuilder.java:140)
 	at org.springframework.boot.jdbc.DataSourceBuilder.build(DataSourceBuilder.java:72)
 	at org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration$Generic.dataSource(DataSourceConfiguration.java:125)

I suggest to improve that so that our failure analyzer catch that and provide a dedicated error message.

We can then add support for SimpleDriverDataSource in 2.3.x as a fallback for this scenario. Adding such support is required for r2dbc anyway.

[snicoll]

@nosan thank you for your effort on this but I am not keen to bring SimpleDriverDataSource in 2.1.x. Looking at the issue, avoiding the embedded configuration to kick in if an url is set sounds like a safer and more isolated change to me. I've just done that and I've reopened the related issue. Thanks again.