fix garbage coordinates when map matched route has uturn

[kevinkreiser]

fixes #2442

[kevinkreiser]

as @dnesbitt61 mentioned the match index can be -1 but only in the case that we dont need to trim. sadly the trimming datastructure is a pair and so you have to specify both first and second. in this case, one of them doesnt need to be set. to get around this i assign one at a time and rely on the default initializer to intialize the pair with false and an invalid lat lon etc

[danpat]

We should follow up on this with a test - if we can dream up how to make one. It's proved troublesome.

[kevinkreiser]

so the request that exposes this ends up showing this at the important part of the code:

(gdb) p *prev_segment
$9 = {edgeid = {value = 397962009178}, source = 0, target = 1, first_match_idx = -1, 
  last_match_idx = -1, discontinuity = false}
(gdb) p *segment
$10 = {edgeid = {value = 985399450202}, source = 0, target = 0.974345565, 
  first_match_idx = -1, last_match_idx = 25, discontinuity = false}
(gdb) p *next_segment
$11 = {edgeid = {value = 1357316774490}, source = 0.0256544352, target = 1, 
  first_match_idx = 25, last_match_idx = -1, discontinuity = false}

basically it turns onto an edge and then just before reaching the end of the edge it turns around and leaves the edge.

so i made a test case for this:

TEST(Standalone, UturnTrimmingAsan) {
  const std::string ascii_map = R"(
A--1--2--B
         |
         |
D--3--4--C--5--6--E
                                )";

  const gurka::ways ways = {
      {"AB", {{"highway", "primary"}}},
      {"BC", {{"highway", "primary"}}},
      {"DCE", {{"highway", "primary"}}},
  };

  const auto layout = gurka::detail::map_to_coordinates(ascii_map, 10);
  auto map = gurka::buildtiles(layout, ways, {}, {}, "test/data/uturn_asan");

  auto result =
      gurka::match(map, {"2", "6", "3"}, "through", "auto", R"({"penalize_immediate_uturn":false})");
}

But it doesnt expose the same problem..

[purew]

Shouldn't the result be checked?