java.util.UnknownFormatConversionException: Conversion = '.' in GTFS GraphQL API when an invalid combination of street modes is specified

[miklcct]

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Expected behavior

The error message is descriptive.

Observed behavior

The GraphQL error says java.util.UnknownFormatConversionException: Conversion = '.'

The log says

java.util.UnknownFormatConversionException: Conversion = '.'
        at java.base/java.util.Formatter.parse(Formatter.java:2852)
        at java.base/java.util.Formatter.format(Formatter.java:2774)
        at java.base/java.util.Formatter.format(Formatter.java:2728)
        at java.base/java.lang.String.formatted(String.java:4452)
        at org.opentripplanner.apis.gtfs.mapping.routerequest.ModePreferencesMapper.getStreetMode(ModePreferencesMapper.java:111)
        at org.opentripplanner.apis.gtfs.mapping.routerequest.ModePreferencesMapper.setModes(ModePreferencesMapper.java:35)
        at org.opentripplanner.apis.gtfs.mapping.routerequest.RouteRequestMapper.toR

Version of OTP used (exact commit hash or JAR name)

2.7.0-SNAPSHOT

Data sets in use (links to GTFS and OSM PBF files)

irrelevant

Command line used to start OTP

irrelevant

Router config and graph build config JSON

Just need to enable the GraphQL API

Steps to reproduce the problem

Send a route request containing 3 street modes (which aren't supported) for the access.