UriTemplate redundantly percent encodes literal part

[bodewig]

When using UriTemplate with a literal part using reserved characters the part is percent encoded twice. For example

new UriTemplate("https://example.org/foo and bar/{baz}").expand("xyzzy")

yields https://example.org/foo%2520and%2520bar/xyzzy rather than the expected https://example.org/foo%20and%20bar/xyzzy. I think this happens because UriTemplate.expand first constructs and expands a Spring Framework UriTemplate from the literal part (which adds percent encoding), builds a UriComponentsBuilder from the result and later calls build with no arguments on this UriComponentsBuilder which adds another layer of percent encoding. I think it would be possible to percent encode all variable values beforehand and then invoke build(false) instead, but I haven't checked all code paths.

Note that when using UriTemplate with a properly percent-encoded literal part to begin with, things become even worse because of spring-projects/spring-framework#24094.

new UriTemplate("https://example.org/foo%20and%20bar/{baz}").expand("xyzzy")

yields https://example.org/foo%252520and%252520bar/xyzzy.

[odrotbohm]

I followed @rstoyanchev's advice from spring-projects/spring-framework#24094 and avoid Spring's UriTemplate entirely. Also backported to 1.0.x via #1130.

[gregturn]

Possibly related to #593. If so, and if resolved, there’s a great test case we’ll be a me to add there to avoid regressions.

[odrotbohm]

I revisited encoding related tickets and am just polishing up a fix for #593.

[bodewig]

Great, many thanks @odrotbohm !