Till Rohrmann created FLINK-3441:
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Summary: Revisit quickstarts exclusion policy
Key: FLINK-3441
URL: https://issues.apache.org/jira/browse/FLINK-3441
Project: Flink
Issue Type: Improvement
Components: Quickstarts
Affects Versions: 1.0.0
Reporter: Till Rohrmann
Priority: Minor
Flink provides quickstart projects to quickly set up a Flink project. In order
to decrease the size of the resulting jar, the predefined {{pom.xml}} file
contains a list of excluded dependencies.
The problem with this approach is two-fold: First of all, the list seems to be
rather arbitrary. Why excluding {{org.apache.commons:commons-math}} but not
{{org.apache.commons:commons-math3}}? It seems as if this list would have to be
kept up to date with every changing dependency of Flink.
Secondly and the more severe problem is the following: The exclusions assume
that Flink always provides a compatible version for an excluded dependency.
However, since the exclusions are not bound to a specific version, this won't
necessarily be true. For example, {{snappy-java}} is excluded from the user job
jar, because Flink with Hadoop {{2.3.0}} comes with {{snappy-java:1.0.5}}.
However, the {{kafka-clients:0.9.0}} which comes with the
{{flink-connector-kafka-0.9}} dependency has a transitive dependency on
{{snappy-java:1.1.1.7}}. Consequently, this dependency will be excluded from
the user job jar per default. If version {{1.1.1.7}} is not compatible to
{{snappy-java:1.0.5}}, then the program will crash at runtime. This will be
very hard to understand for the user because it is a very subtle bug since the
exclusions also affect the transitive dependencies.
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