I set up an optional copy artifact step for a specific build, which is determined by a build parameter (e.g. $SOURCE_BUILD_NO).

The expectation was to leave the parameter empty if I didn't want to copy anything, as it couldn't have copied anything, and move on, just like when entering a build number for a non-existing build.

That resulted in a build failure.

FATAL: For input string: "$SOURCE_BUILD_NO"
java.lang.NumberFormatException: For input string: "$SOURCE_BUILD_NO"

Workarounds:

• Entering the build number of a non-existing build or build without artifacts, e.g. -5.
• Using conditional build step plugin.