exec and Bash vars, false-postive "single quoted string containing a variable found on line"

[andreashaerter]

puppet-lint detects Bash vars in single quoted strings and reports "single quoted string containing a variable found on line".

The following example shows the problem:

class foobar() {
  # wrong behavior
  # puppet-lint detects the Bash var ${FOOBAR} and reports
  # "ERROR: single quoted string containing a variable found on line"
  exec{ 'wrong single quoted string containing a variable':
    command   => 'set -e; set -u;
                  FOOBAR=\'this is a Bash var\';
                  echo "Bash: ${FOOBAR}";',
    path      => [ '/usr/local/bin', '/sbin', '/bin', '/usr/sbin', '/usr/bin' ],
    provider  => 'shell',
    logoutput => true,
  }
}

I don't know any Ruby nor the puppet-lint internals. And I see that the basic problem is: Bash uses the same variable syntax as Puppet. So searching for Puppet vars in exec command/onlyif/unless will find Bash vars.

Therefore the only quick idea I got to solve/soften this problem is to adjust the "single quoted string containing a variable found on line" error check:

1. If a var in a single quoted string was found, check if the string belongs to an exec's command/onlyif/unless.
2. If so, check if the found variable is defined in Puppet:
   • If so, report an ERROR
   • If not, report NO error (assuming it is a non-var var belonging to the exec command's shell code).

As puppet-lint is able to detect 'top-scope variable being used without an explicit namespace' there already seems to be some intelligence regarding Puppet vars in strings. Maybe a comparable procedure is able to solve the false-positive-bash-var errors.

[rharrison10]

I am also seeing this issue with the command parameter for cron resources.

[matthewianmorgan]

Unfortunately this isn't as simple as the description suggests.

A class that I have defined has a parameter that may take bash variables. So simply ignoring command, onlyif and unless statements won't do the complete job.

[stevenpost]

Since this issue is still open and a similar one was closed, I'll add my comments here, even though it is a rather old ticket.
The pull request in [1] changes this from an error to a warning.
Also it's not just exec statements where these occur.
I use the file_line type from stdlib to manage some variables in configuration files (which are actually bash scripts executed within init scripts), sometimes these will contain bash variables and thus need to be treated as literal strings. I imagine people managing their yum repo configs are also affected.

[1] #189

[xarses]

I created pull #234 changing @andreashaerter example around to use double quotes should work now

class foobar() {
  # wrong behavior
  # puppet-lint detects the Bash var ${FOOBAR} and reports
  # "ERROR: single quoted string containing a variable found on line"
  exec{ 'wrong single quoted string containing a variable':
    command   => "set -e; set -u;
                  FOOBAR=\'this is a Bash var\';
                  echo \"Bash: \${FOOBAR}\";",
    path      => [ '/usr/local/bin', '/sbin', '/bin', '/usr/sbin', '/usr/bin' ],
    provider  => 'shell',
    logoutput => true,
  }
}

[rodjek]

#234 has been merged into master, you will now be able to do what @xarses has suggested above.