jjohannes opened a new issue, #3437: URL: https://github.com/apache/logging-log4j2/issues/3437
This is about getting an error like the following when compiling with a `module-info.java` and the compiler flags `-Xlint:all` and `-Werror`: ``` > Compilation failed; see the compiler output below. log4j-api-2.24.3.jar(/org/apache/logging/log4j/message/ParameterizedMessage.class): warning: Cannot find annotation method 'replacement()' in type 'InlineMe': class file for com.google.errorprone.annotations.InlineMe not found log4j-api-2.24.3.jar(/org/apache/logging/log4j/message/ParameterizedMessage.class): warning: Cannot find annotation method 'imports()' in type 'InlineMe' log4j-api-2.24.3.jar(/org/apache/logging/log4j/status/StatusData.class): warning: Cannot find annotation method 'value()' in type 'SuppressFBWarnings': class file for edu.umd.cs.findbugs.annotations.SuppressFBWarnings not found log4j-api-2.24.3.jar(/org/apache/logging/log4j/status/StatusData.class): warning: Cannot find annotation method 'justification()' in type 'SuppressFBWarnings' log4j-api-2.24.3.jar(/org/apache/logging/log4j/util/SystemPropertiesPropertySource.class): warning: Cannot find annotation method 'value()' in type 'ServiceProvider': class file for aQute.bnd.annotation.spi.ServiceProvider not found log4j-api-2.24.3.jar(/org/apache/logging/log4j/util/SystemPropertiesPropertySource.class): warning: Cannot find annotation method 'resolution()' in type 'ServiceProvider' log4j-api-2.24.3.jar(/org/apache/logging/log4j/util/Activator.class): warning: Cannot find annotation method 'value()' in type 'Headers': class file for org.osgi.annotation.bundle.Headers not found log4j-api-2.24.3.jar(/org/apache/logging/log4j/util/Activator.class): warning: Cannot find annotation method 'name()' in type 'Header': class file for org.osgi.annotation.bundle.Header not found log4j-api-2.24.3.jar(/org/apache/logging/log4j/util/Activator.class): warning: Cannot find annotation method 'value()' in type 'Header' log4j-api-2.24.3.jar(/org/apache/logging/log4j/util/Activator.class): warning: Cannot find annotation method 'name()' in type 'Header' log4j-api-2.24.3.jar(/org/apache/logging/log4j/util/Activator.class): warning: Cannot find annotation method 'value()' in type 'Header' error: warnings found and -Werror specified 1 error 11 warnings ``` The error is triggered by using classes from Log4j that use annotations on public members from the annotation libraries indicated in the error message. There are two _layers_ of missing dependencies that cause this: 1. The annotation library's Jar file (e.g. `com.google.errorprone:error_prone_annotations:2.36.0`) is not on the Classpath/Module Path 2. The annotation library's Java Module (e.g. `com.google.errorprone.annotations`) is not defined as `require static` in the corresponding `module-info.class` of Log4j For (1) it's debatable if it can be fixed in a good way, as POM does not have a scope that resembles [Gradle's compileOnlyApi scope](https://www.baeldung.com/gradle-dependency-management#2-types-of-configuration): visible transitively but ONLY on the compile classpath. For (2) you can argue that it is a bug, because if the code of Log4j would be compiled on the Module Path (i.e. with the compiler checking the `module-info.java`) it would not compile. ### Workarounds for users (1) - Adding the missing dependencies directly as `compileOnly` (`<provided>`) to your own project. - Patching the POM metadata with a rule (possible in Gradle) (2) - Calling the compiler with additional `--add-reads` arguments - Patching the `module-info.class` itself (possible in Gradle with plugin) ### Possible improvements in Log4j (1) This was already discussed [here](https://github.com/apache/logging-log4j2/issues/3110#issuecomment-2423586754). The dependencies marked as `<provided>` [here](https://github.com/apache/logging-log4j2/blob/94d3227165f22993c126c9ec19f3ddc03abe967c/log4j-parent/pom.xml#L829-L858) would need to be switched to `<compile>`. But that has the unwanted effect that ALL users will get them as unnecessary RUNTIME dependencies. There is the option to publish additional [Gradle Metadata](https://github.com/gradle/gradle/blob/master/platforms/documentation/docs/src/docs/design/gradle-module-metadata-latest-specification.md) that supports the `compileOnlyApi` scope. If you are interested, I can make a contribution for that as I maintain the [Maven plugin for publishing such metadata with Maven](https://github.com/jjohannes/gradle-module-metadata-maven-plugin) (it's used by Jackson for example). But I can understand if you don't want to have additional complexity in your build setup. (2) Maybe you can check if the additional requires could be added to all `module-info`: ``` requires static transitive com.google.errorprone.annotations; requires static transitive com.github.spotbugs.annotations; requires static transitive biz.aQute.bnd.annotation; requires static transitive org.osgi.annotation.bundle; ``` *`requires static` works also, but conceptually `requires static transitive` feels more correct as the annotations are transitively visible. ----- All of this can also be avoided by turning of the `classfiles` line check of `javac`... I can understand if there is nothing you can/want to do at this point. Then, feel free to close this issue. Having this written down can be helpful for users who run into this in any case. If you want to do something I can help with, let me know. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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