swagger generate PHP client

[lexo13]

java -jar swagger-codegen-cli-2.2.3.jar generate -i ./api-docs-gh-pages/swagger.json -l php -o ./mes_classes

[main] INFO io.swagger.codegen.AbstractGenerator - writing file /home/franck/temp/./arfarf/SwaggerClient-php/docs/Model/TrackedOrderProduct.md
Exception in thread "main" java.lang.RuntimeException: Could not generate api file for 'AnalyticsOptimisations'
at io.swagger.codegen.DefaultGenerator.generateApis(DefaultGenerator.java:495)
at io.swagger.codegen.DefaultGenerator.generate(DefaultGenerator.java:700)
at io.swagger.codegen.cmd.Generate.run(Generate.java:285)
at io.swagger.codegen.SwaggerCodegen.main(SwaggerCodegen.java:35)
Caused by: java.lang.NullPointerException
at java.util.TreeMap.put(TreeMap.java:563)
at java.util.TreeSet.add(TreeSet.java:255)
at java.util.AbstractCollection.addAll(AbstractCollection.java:344)
at java.util.TreeSet.addAll(TreeSet.java:312)
at io.swagger.codegen.DefaultGenerator.processOperations(DefaultGenerator.java:897)
at io.swagger.codegen.DefaultGenerator.generateApis(DefaultGenerator.java:412)