JOptCommandLinePropertySource selects property names in an inconsistent way [SPR-17639]

[spring-projects-issues]

chludwig-haufe opened SPR-17639 and commented

I recently had to build a Spring Boot command line application whose application context depends on command line options. I specified the qualified property names (i.e., "<prefix>.<prop-name>" as option alias names using the OptionParser#addAll(List<String>) method of JOpt's fluent interface. I injected a customized StandardEnvironment with a JOptCommandLinePropertySource based on the parsed command line arguments into the SpringApplication. To my surprise, however, some of the properties were never bound to the corresponding @ConfigurationProperties object.

I found that this was caused by the implementation of JOptCommandLinePropertySource#getPropertyNames(): A comment in the source code claims "only the longest name is used for enumerating". However, the implementation always returns the last element of OptionSpec#options(). This is, in general, not the longest option name, because OptionSpec#options()

• first clusters the option names into short and long options and
• then sorts these groups lexicographically, respectively.

For some options, JOptCommandLinePropertySource#getPropertyNames() therefore contained the qualified alias name required for binding the property to the @ConfigurationProperties object, while for other options it contained the unqualified option alias. Admittedly, the documentation of JOptCommandLinePropertySource never specifies which property names are enumerated; but I can't see a scenario where the current behavior is useful.

This ticket's reference URL points to a JUnit class that demonstrates this behavior. The test class also includes alternative property name selection strategies that would work better in my scenario. (I wonder why JOptCommandLinePropertySource#getPropertyNames() needs to filter the option alias names in the first place.)

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Affects: 5.0.11, 5.1.3, 5.1.4

Reference URL: https://github.com/chludwig-haufe/JOptCommandLinePropertySource-Issues/blob/master/src/test/java/com/haufe/bugreports/spring/wrongpropertynamedemo/JOptCommandLinePropertySourceTests.java

[spring-projects-issues]

Stéphane Nicoll commented

Thanks for the report but this issue tracker does not manage Spring Boot issues at all. Spring Boot has its own issue tracker: https://github.com/spring-projects/spring-boot

[spring-projects-issues]

chludwig-haufe commented

Hu? AFAIK, JOptCommandLinePropertySource is a class of Spring Framework, not Spring Boot. I don't think the Spring Boot authors could do anything about it.

[spring-projects-issues]

Stéphane Nicoll commented

Apologizes, I mixed up with our support in spring-boot-cli.