Issue Details

Description
When importing a snippet from a separate file that contains a directive wrapping a {block} placeholder (such as reverse_proxy), Caddy v2.11 silently ignores the provided block during the import.

This bug only seems to happen if the snippet is in a separate file.

Steps to reproduce
./Caddyfile

{
  admin off
  auto_https off
}

import snippets

:8080 {
  import test {
    this_is_nonsense
  }
}

./snippets

(test) {
  reverse_proxy {
    {block}
  }
}

run

docker run --rm -p 8080:8080 -v "$PWD:/etc/caddy:ro" caddy:2.11 caddy run --config /etc/caddy/Caddyfile

Expected Behavior (Caddy v2.10)
In Caddy v2.10, the {block} is injected correctly. The parser evaluates the contents, sees the invalid this_is_nonsense subdirective inside reverse_proxy, and rightfully refuses to start:

$ docker run --rm -p 8080:8080 -v "$PWD:/etc/caddy:ro" caddy:2.10 caddy run --config /etc/caddy/Caddyfile
Error: adapting config using caddyfile: parsing caddyfile tokens for 'reverse_proxy': unrecognized subdirective this_is_nonsense

Actual Behavior (Caddy v2.11)
In Caddy v2.11, the {block} is entirely ignored. The reverse_proxy directive evaluates as empty, so Caddy happily starts up with no errors.

$ curl -i http://127.0.0.1:8080/
HTTP/1.1 503 Service Unavailable
Server: Caddy
Date: Mon, 09 Mar 2026 20:19:33 GMT
Content-Length: 0

Assistance Disclosure

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ChatGPT improved the issue description