"Don't build unnecessary jars" causes built-with-aspect failure

[tpasternak]

Description of the bug:

intellij/aspect/intellij_info_impl.bzl

Lines 789 to 802 in 78303d5

	for jar in java_outputs:
	if jar.ijar:
	jar_artifacts.append(jar.ijar)
	elif jar.class_jar and not should_optimize_building_jars:
	jar_artifacts.append(jar.class_jar)
	if hasattr(jar, "source_jars") and jar.source_jars:
	source_jar_artifacts.extend(_list_or_depset_to_list(jar.source_jars))
	elif hasattr(jar, "source_jar") and jar.source_jar:
	source_jar_artifacts.append(jar.source_jar)
	if should_optimize_building_jars:
	if len(source_jar_artifacts) == 0 or len(jar_artifacts) == 0:
	jar_artifacts.extend([jar.class_jar for jar in java_outputs.jars if jar.class_jar])

In line 789 we assume that java_outputs is an iterable (it is a List), while in the other place, in line 801 we assume it has an attribute named jars. Hence, it is impossible to import even this repository (bazelbuild/intellij). It results in

Error: 'list' value has no field or method 'jars'

[tpasternak]

cc @nkoroste

[nkoroste]

Related to #5515
The fix should be simple

[tpasternak]

Yeah, but how it was working for you? Will it work if we just change java_outputs.jars to java_outputs?

[nkoroste]

Honestly I don't remember anymore, this PR took so long to get it. All existing and new tests are passing in this public repo on this PR.

Did you inspect the output of java_outputs in the passing and failing case? Curious to see how it looks like and why you guys are only hitting it internally if I'm understanding it right.

[tpasternak]

so java_outputs is just a list. Is it possible that in your case the condition if len(source_jar_artifacts) == 0 or len(jar_artifacts) == 0: is never satisfied?

[nkoroste]

so java_outputs is just a list. Is it possible that in your case the condition if len(source_jar_artifacts) == 0 or len(jar_artifacts) == 0: is never satisfied?

Yep that could be it.

p.s. thanks for the fix!