With or without trailing slash will be matched to different endpoints

[ZSSVE]

Describe the bug

Hi, during our upgrade of Sanic from 19.9.0 to a higher one at 21.9.3, we ran into a seemly behavior change for path routing.

A clear and concise description of what the bug is, make sure to paste any exceptions and tracebacks.

With two GET endpoints

1. /test/
2. /test/< name>

In Sanic 19.9.0,

• curl 'http://127.0.0.1:8000/test/' will be routed to endpoint 1

In Sanic 21.9.3,

• curl 'http://127.0.0.1:8000/test/' will be routed to endpoint 2 with empty string as parameter

In both Sanic 19.9.0 and 21.9.3, curl 'http://127.0.0.1:8000/test' resolves to endpoint 1, expectedly.

Code snippet
Relevant source code, make sure to remove what is not necessary.

from sanic import Sanic
from sanic.response import text

app = Sanic("MyHelloWorldApp")

@app.get("/test/")
async def hello_test(request):
    return text("Hey test")

@app.get("/test/<name>")
async def hello_test_name(request, name):
    return text("Hello, " + name)


if __name__ == "__main__":
    app.run("localhost", 8000)

Expected behavior
A clear and concise description of what you expected to happen.

This backward incompatibility does not seem to be documented.

Environment (please complete the following information):

• OS: [e.g. iOS] big sur
• Version [e.g. 0.8.3] 21.9.3

Additional context
Add any other context about the problem here.

We'll appreciate helps on a way to keep the old behavior for a smooth transition.

[Tronic]

This will be mostly fixed in the next release, with the parameters no longer matching empty strings by default. I recommend always setting Sanic("yourapp", strict_slashes=True) to avoid such issues with all Sanic versions.

[ZSSVE]

This will be mostly fixed in the next release, with the parameters no longer matching empty strings by default. I recommend always setting Sanic("yourapp", strict_slashes=True) to avoid such issues with all Sanic versions.

Thank you for the reply! Since in pre-21.3 version, both /test/ and /test seem to route to the endpoint without parameter (hello_test), we might have existing callers using both. Just adding strict_slashes=True may break some of the callers. One way we are thinking about temporarily is to set strict_slashes=True and add a pair of routes (with and without trailing slash) for all our endpoints, but we are unsure if there are other subtle differences from the pre-21.3 behavior.

[ashleysommer]

Yeah, this was a regression (or unintended change in behavior) in v21.3, caused by the introduction of the new Router, it was not corrected until recently. As @Tronic said, this will revert to the pre-21.3 behavior in the next release (v22.3), and you will not need to add strict_slashes=True.

[Tronic]

Closing as duplicate of #2391 #2384 #2239

PR fixing the regression: sanic-org/sanic-routing#58
An open issue with relevant discussion: sanic-org/sanic-guide#92