Missing DEF_VERSION produces obscure error message

[tallica]

Steps to reproduce

Create meta definition with missing DEF_VERSION and build it

ruby-build-essentials.def:

DEF_TYPE="meta"
DEF_NAME="ruby-build-essentials"
DEF_REQUIREMENTS="libffi libressl readline yaml"
DEF_CLEAN_USELESS=NO

build log:

$ s build ruby-build-essentials
  Requested Build of: ruby-build-essentials
  Installing: Ruby-build-essentials, version: , with requirements: libffi libressl readline yaml
    libffi (5 of 5 remaining)
     → Config: /Users/michal/.sofin/logs/sofin-libffi.config -> /Users/michal/.sofin/logs/sofin-libffi.config.result
    libressl (4 of 5 remaining)
     → Config: /Users/michal/.sofin/logs/sofin-libressl.config -> /Users/michal/.sofin/logs/sofin-libressl.config.result
    readline (3 of 5 remaining)
     → Config: /Users/michal/.sofin/logs/sofin-readline.config -> /Users/michal/.sofin/logs/sofin-readline.config.result
    yaml (2 of 5 remaining)
     → Config: /Users/michal/.sofin/logs/sofin-yaml.config -> /Users/michal/.sofin/logs/sofin-yaml.config.result
    ruby-build-essentials (1 of 5)
     » Meta bundle detected.
  » Task crashed!
      error: Failed with an empty _verfile!