`URIEditor` prevents configuring URIs with encoded # sign

[AdrianDiemerDev]

I have a ConfigurationProperties class containing a property of type java.net.URI.

If I configure a value of file:///C:/some/path/with/#/in/it it (correctly) gets converted to a URI with a fragment component (which is not what I need in this case).

However, if I configure the value as a correctly encoded URI like this file:///C:/some/path/with/%23/in/it, it (incorrectly) gets converted to this URI: file:///C:/some/path/with/%2523/in/it.

I don't see a way to configure this URI so it gets bound correctly.

The reason for this is that the org.springframework.beans.propertyeditors.URIEditor tries to guess which part of the URI is correctly encoded and which isn't which is a task that's impossible to do correctly for all cases.

This has been improved upon several times in #10673, #21123, and #11743, but I think the approach is fundamentally flawed and the URIEditor should just not try to fix incorrectly encoded URIs by default.

The best workaround I could find was to use URLs instead of URIs.

[rstoyanchev]

To handle an encoded URI, the encode property should be off. This works:

String s = "file:///C:/some/path/with/%23/in/it";
URI uri = new URIEditor(false).createURI(s);
assertThat(uri.toString()).isEqualTo(s);

[AdrianDiemerDev]

Yes, I know about the constructor but that doesn't help with the ConfigurationProperties binding because the binding uses a hard coded instance of URIEditor with encode = false. I couldn't find any way to replace that instance.

But even if it is somehow possible to replace it there, I don't think interpreting RFC3986 compliant URIs erroneously should be the default. I get that the idea is to make it more tolerant to wrongly encoded URIs but I don't think that should go at the expense of supporting correct URIs.

Though, I have no idea how to change this without introducing a breaking change...

[rstoyanchev]

There is no way to change this without breaking someone else. Compatibility aside, what change did you actually have in mind?

[AdrianDiemerDev]

Well, as mentioned before, in a perfect world, I feel like a standard conform URI should always be interpreted correctly by default.

But since that would be breaking, I guess the next best option would be to allow overriding the URIEditor instance when instantiating a new org.springframework.boot.context.properties.bind.Binder as well as for the default Binder.

I don't really have a sufficient understanding of the classes involved here to outline a proposed change.

[rstoyanchev]

Have you tried something like the below?

@Bean
static CustomEditorConfigurer customEditorConfigurer() {
    CustomEditorConfigurer configurer = new CustomEditorConfigurer();
    configurer.setPropertyEditorRegistrars(new PropertyEditorRegistrar[] {
            registry -> registry.registerCustomEditor(URI.class, new URIEditor(false))
    });

    return configurer;
}

As far as I can tell, Binder uses BindConverter, which is customized through a Consumer<PropertyEditorRegistry> that's configured to copy from the BeanFactory.