Issue #7748 - Backport of allow override of path mapping behavior in ServletContextHandler

[gregw]

backport and fix to 9.4 for #7748

[joakime]

[INFO] --- license-maven-plugin:4.1:check (check-java-headers) @ jetty-project ---
[INFO] Checking licenses...
[WARNING] Missing header in: /home/jenkins/agent/workspace/jetty.project_PR-7834/jetty-servlet/src/test/java/org/eclipse/jetty/servlet/RegressionServletTest.java
[WARNING] Missing header in: /home/jenkins/agent/workspace/jetty.project_PR-7834/jetty-servlet/src/test/java/org/eclipse/jetty/servlet/RegexServletTest.java

Keep in mind that Jetty 9.4.x has the old EPL 1.0 license headers.

[lachlan-roberts]

What is the reason for this change?
This change is not present in 10 & 11.

[gregw]

@lachlan-roberts my intention is to move this change forward into 10 & 11.
I believe it is needed to make the methods getPathMatch and getPathInfo symmetric.

Specifically I would expect either pathMatch==/test && pathInfo==/info or pathMatch==/test/info && pathInfo==null, but never pathMatch==/test && pathInfo==null, since that loses information. Currently we get the later behavior!

So I have added the following test.

    @Test
public void testPathInfo()
    {
        RegexPathSpec spec = new RegexPathSpec("^/test(/.*)?$");
        assertTrue(spec.matches("/test/info"));
        assertThat(spec.getPathMatch("/test/info"), equalTo("/test"));
        assertThat(spec.getPathInfo("/test/info"), equalTo("/info"));

        spec = new RegexPathSpec("^/[Tt]est(/.*)?$");
        assertTrue(spec.matches("/test/info"));
        assertThat(spec.getPathMatch("/test/info"), equalTo("/test/info"));
        assertThat(spec.getPathInfo("/test/info"), nullValue());
    }

Note that this issue was not apparent in 10 & 11, because they do not use these methods to set the servletPath and pathInfo, but rather work it out differently (I'll check exactly why when I port this change forward).

[joakime]

The UriTemplatePathSpec has the same issue with the difference in behavior.

Example path spec ... /{first}/static/{other}

[gregw]

I just did a force push to squash this to 1 commit so I can start work on porting forward to 10, 11 etc.
yeah I know I always say don't do force pushes.... do as I say and not as I do :)

[gregw]

@joakime @lachlan-roberts review please