Add regression test for ambiguous router matching #5235
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Prior to 1.3, the router had ambiguous matching for prefix routes if a route with a better prefix match existed for another hostname. The router would add the better prefix match to the set of reduced candidates, but not match it because of the hostname mismatch. After failing to match any candidates in the reduced set, the router would then proceed checking a larger candidate set, selecting the first match. Because the larger candidate set was effectively sorted by creation date, a route with a shorter, matching prefix would match instead of a more specific prefix created later. 2683b86 fixed this issue in most cases by adding the longest path length to route sorting criteria. It was originally designed to fix a different issue, and as such did not test this case. There are some remaining edge cases. For example: If created in the following order, versions prior to 1.3 would match "example.com/a/b/c" to the first route, whereas 1.3+ matches the second: "hosts":{"example.com"} "paths":{"/a"} "hosts":{"example.com"} "paths":{"/a/b"} "hosts":{"example.net"} "paths":{"/a/b/c"} 1.3+ will, however, still match the first route in this set of routes: "hosts":{"example.com"} "paths":{"/a", "/long/long/path"} "hosts":{"example.com"} "paths":{"/a/b"} "hosts":{"example.net"} "paths":{"/a/b/c"} Manually setting regex_priority on problem is still the recommended means of making the second route match in the second set.
bungle
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Nov 20, 2019
hutchic
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Nov 21, 2019
Prior to 1.3, the router had ambiguous matching for prefix routes if a route with a better prefix match existed for another hostname. The router would add the better prefix match to the set of reduced candidates, but not match it because of the hostname mismatch. After failing to match any candidates in the reduced set, the router would then proceed checking a larger candidate set, selecting the first match. Because the larger candidate set was effectively sorted by creation date, a route with a shorter, matching prefix would match instead of a more specific prefix created later. 2683b86 fixed this issue in most cases by adding the longest path length to route sorting criteria. It was originally designed to fix a different issue, and as such did not test this case. There are some remaining edge cases. For example: If created in the following order, versions prior to 1.3 would match "example.com/a/b/c" to the first route, whereas 1.3+ matches the second: "hosts":{"example.com"} "paths":{"/a"} "hosts":{"example.com"} "paths":{"/a/b"} "hosts":{"example.net"} "paths":{"/a/b/c"} 1.3+ will, however, still match the first route in this set of routes: "hosts":{"example.com"} "paths":{"/a", "/long/long/path"} "hosts":{"example.com"} "paths":{"/a/b"} "hosts":{"example.net"} "paths":{"/a/b/c"} Manually setting regex_priority on problem is still the recommended means of making the second route match in the second set.
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Summary
Add regression test for an ambiguous router match case involving matching prefixes on non-matching hostnames. 2683b86 fixed this issue, but was designed to address a different issue, and did not have tests for this case.
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