Fix json rendering of large osm ids

CHANGELOG.md

@@ -78,6 +78,7 @@
       - FIXED: Ensure required file check in osrm-routed is correctly enforced. [#6655](https://github.com/Project-OSRM/osrm-backend/pull/6655)
       - FIXED: Correct HTTP docs to reflect summary output dependency on steps parameter. [#6655](https://github.com/Project-OSRM/osrm-backend/pull/6655)
       - ADDED: Extract prerelease/build information from package semver [#6839](https://github.com/Project-OSRM/osrm-backend/pull/6839)
+      - FIXED: Fix json rendering problem for large osm ids [#7096](https://github.com/Project-OSRM/osrm-backend/pull/7096)
     - Profiles:
       - FIXED: Bicycle and foot profiles now don't route on proposed ways [#6615](https://github.com/Project-OSRM/osrm-backend/pull/6615)
       - ADDED: Add optional support of cargo bike exclusion and width to bicyle profile [#7044](https://github.com/Project-OSRM/osrm-backend/pull/7044)

include/util/json_renderer.hpp

@@ -54,7 +54,10 @@ template <typename Out> struct Renderer
         // `fmt::memory_buffer` stores first 500 bytes in the object itself(i.e. on stack in this
         // case) and then grows using heap if needed
         fmt::memory_buffer buffer;
-        fmt::format_to(std::back_inserter(buffer), FMT_COMPILE("{:.10g}"), number.value);
+        if (static_cast<std::uint64_t>(number.value) == number.value)
+            fmt::format_to(std::back_inserter(buffer), FMT_COMPILE("{}"), static_cast<std::uint64_t>(number.value));
+        else
+            fmt::format_to(std::back_inserter(buffer), FMT_COMPILE("{:.10g}"), number.value);
 
         write(buffer.data(), buffer.size());
     }

unit_tests/util/json_render.cpp

@@ -87,8 +87,13 @@ BOOST_AUTO_TEST_CASE(test_json_issue_6531)
     BOOST_CHECK_EQUAL(output, "0.1234567892");
 
     output.clear();
-    renderer(123456789123456789.);
-    BOOST_CHECK_EQUAL(output, "1.234567891e+17");
+    renderer(12345678912345678.);
+    BOOST_CHECK_EQUAL(output, "12345678912345678");
+
+    // handle large osm ids
+    output.clear();
+    renderer(1000396615812);
+    BOOST_CHECK_EQUAL(output, "1000396615812");
 }
 
 BOOST_AUTO_TEST_SUITE_END()