Logger in BEF is not working after initial Bazel builds start

[plaird]

This started as a logback issue, but now it is something different. I think what is happening is once we start invoking Bazel commands, and hook stdout and stderr for that, our logging to outer Eclipse no longer works.

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We revamped the logging for the feature. But on my machine, file logging is not working correctly. I tried a bunch of different things, but in the end I found a clue that suggests a load ordering problem.

I have added this check to our Eclipse logging facade:

bazel-eclipse/plugin-core/src/main/java/com/salesforce/bazel/eclipse/EclipseLoggerFacade.java#L153

And it indicates the logback is indeed in the classpath, but for some reason my log factory was initialized too early or in a different plugin such that logback was not found:

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.

com.salesforce.bazel.eclipse.core: EclipseLoggerFacade could not configure file (INFO, DEBUG) logging. LoggerFactory is of type [class org.slf4j.helpers.NOPLoggerFactory] but needed [ch.qos.logback.classic.LoggerContext] to configure the file log. The class ch.qos.logback.classic.LoggerContext is NOW available in the classpath, which means there was a startup loading issue. The class wasn't there when logging was initialized. See bazel-eclipse/docs/dev/logging.md for more details.

[plaird]

I am also seeing this error on startup from the Gradle plugin only when the BEF is installed:

An internal error occurred during: "Loading available Gradle versions".
Class ch.qos.logback.classic.LoggerContext does not implement the requested interface org.slf4j.ILoggerFactory

[plaird]

I suspect these issues happen when M2Eclipse is also installed. I see this at startup in my Eclipse that is affected when BEF is not installed:

org.eclipse.m2e.logback.configuration: The org.eclipse.m2e.logback.configuration bundle was activated before the state location was initialized. Will retry after the state location is initialized.
org.eclipse.m2e.logback.configuration: Logback config file: /Users/plaird/eclipse-workspace-2018-09b/.metadata/.plugins/org.eclipse.m2e.logback.configuration/logback.1.9.1.20180912-1601.xml
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [bundleresource://517.fwk1850777594:1/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [bundleresource://517.fwk1850777594:2/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [ch.qos.logback.classic.util.ContextSelectorStaticBinder]
org.eclipse.m2e.logback.configuration: Initializing logback

I have ripped out all external logging libs from BEF for the short term until we have time to investigate.
0da5faf

[plaird]

This was resolved by doing what we can to log to the Eclipse platform logger, but we now have a /tmp/bef.log (on Unix) which is a log file fully under our control. We send all log lines there in addition to the platform logger.