[Instrumentation.AspNet] Fix multiple routes of same template in attribute-based routing

[tchowice]

Changes

ASP.NET instrumentation fails to extract route for attribute-based routing, if multiple HTTP methods use the same route template--a common scenario for RESTful APIs. For example:

public class WidgetsController : ApiController
{
    [Route("api/widgets/{id}")]
    public string Get(int id) {...}

    [Route("api/widgets/{id}")]
    public void Put(int id, [FromBody]string value) {...}

    [Route("api/widgets/{id}")]
    public void Delete(int id) {...}
}

In this case, the MS_Subroutes array will have multiple elements, each corresponding to a different HTTP method.

The original code only extracts the route template if there's only one element in the array. The correct thing to do is to just extract the template from the first subroute, since all subroutes have the same template.

It's not possible for MS_Subroutes array to have different templates in its elements. WebAPI would fail to route and throw an exception, if you declare multiple actions for the same method/template

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• Unit tests added/updated
• Appropriate CHANGELOG.md files updated for non-trivial changes
• Changes in public API reviewed (if applicable)

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: Kielek / name: Piotr Kiełkowicz (cf4b953, ecf7ab3, 7eac47d, 6ed976f, 6bde194)
• ✅ login: tchowice (7b8023c, 1d5b33d, 4340ca2)

[Kielek]

Please sign EasyCLA. It is hard requirement to accept any contribution to this repository.

[tchowice]

Please sign EasyCLA. It is hard requirement to accept any contribution to this repository.

Thanks. Working with my company to figure this out.

[tchowice]

Please sign EasyCLA. It is hard requirement to accept any contribution to this repository.

Thanks. Working with my company to figure this out.

[tchowice]

Please sign EasyCLA. It is hard requirement to accept any contribution to this repository.

Okay, I finally got my company to sign the CLA. Please proceed with reviewing!

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 7 days.

[ysolomchenko]

Add an entry to the Changelog

[ysolomchenko]

Update the PR title to start with [Instrumentation.AspNet]

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.73%. Comparing base (71655ce) to head (ecf7ab3).
Report is 601 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2250      +/-   ##
==========================================
+ Coverage   73.91%   76.73%   +2.81%     
==========================================
  Files         267       15     -252     
  Lines        9615      361    -9254     
==========================================
- Hits         7107      277    -6830     
+ Misses       2508       84    -2424     

Flag	Coverage Δ
unittests-Instrumentation.AspNet	76.73% <100.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...on.AspNet/Implementation/HttpRequestRouteHelper.cs	100.00% <100.00%> (ø)

... and 267 files with indirect coverage changes

[Kielek]

@tchowice. Thanks for your contribution. Merging.