flowable/flowable-engine: technical due diligence, read from its repository

The median source file here is 58 lines. 46 files exceed 1,000 lines, the largest being 5,568. Size is not a defect on its own — some problems genuinely live in one place — but these are where merge conflicts, review fatigue and single-owner knowledge concentrate, and they are the first thing that slows an inheriting engineer down.

43 files were marked deprecated over two years ago and still are, the oldest since Dec 2016. A deprecation is a promise to remove. Ask what still depends on these, and whether removing them is scheduled.

2 places in product code build SQL by formatting or joining strings rather than passing parameters. In each, what the code shows going in is a table or column name, a constant, or something the line does not show, not a request's value. Ask whether any value reaches these strings, rather than a parameter.

8 places read data with a deserialiser that executes what it reads (Java object streams). That is safe on data the system wrote itself and remote code execution on anything else. Ask where each one's input comes from.

Nothing in the service initialises an error reporter (Sentry, Rollbar, Bugsnag, Honeybadger or an APM agent). An exception in production reaches a person only if someone is reading the logs, which usually means a customer reports it first.

1 images in the deployment configuration are named without a version or as `latest`. A redeploy can change the software without a commit, a rollback has nothing to roll back to, and nobody can say from the repository what is running.

1 deployments set `replicas: 1`, and nothing (an autoscaler, a disruption budget) adds more. Every deploy and every node drain is downtime, and the availability the buyer inherits has a ceiling.