validate_re() does not correctly match numbers in some cases

[Brian Mathis]

I'm seeing this issue with the current version of stdlib.  When getting numeric data from hiera, or performing math on a variable, validate_re() fails when using the following regex:
    '[0-9]+'

Here are some test cases:

Getting data from hiera

    # Hiera data:
    # ---
    # testvalue: 1234

    FAIL:
        $myvar = hiera('testvalue')
        validate_re( $myvar, '[0-9]+' )

Performing math
    OK:
       $var = 1000
       validate_re( $var, '[0-9+]' )

    FAIL:
       $var2 = 2000 + 1
       validate_re( $var2, '[0-9+]' )

I've had to resort to quoting variables in validate_re, like this:

    OK:

        $var3 = 3000 + 1
        validate_re( "${var3}", '[0-9+]' )

However puppet-lint complains about having only a variable inside double-quotes, so I'm considering solving this with the very ugly:
    validate_re( "X${var3}", 'X[0-9+]' )

Is anyone else seeing this issue?

I have opened a ticket:

    https://tickets.puppetlabs.com/browse/MODULES-865

❧ Brian Mathis

@orev

[jcbollinger]

On Monday, May 19, 2014 6:45:56 PM UTC-5, Brian Mathis wrote:

I'm seeing this issue with the current version of stdlib.  When getting numeric data from hiera, or performing math on a variable, validate_re() fails when using the following regex:
    '[0-9]+'

Fascinating.

 

Here are some test cases:

Getting data from hiera

    # Hiera data:
    # ---
    # testvalue: 1234

    FAIL:
        $myvar = hiera('testvalue')
        validate_re( $myvar, '[0-9]+' )

Performing math
    OK:
       $var = 1000
       validate_re( $var, '[0-9+]' )

    FAIL:
       $var2 = 2000 + 1
       validate_re( $var2, '[0-9+]' )

I've had to resort to quoting variables in validate_re, like this:

    OK:

        $var3 = 3000 + 1
        validate_re( "${var3}", '[0-9+]' )

However puppet-lint complains about having only a variable inside double-quotes, so I'm considering solving this with the very ugly:
    validate_re( "X${var3}", 'X[0-9+]' )

Yet your solution using "${var3}" is perfectly good thing to do to convert a variable of uncertain type to a string.  I'd tell puppet-lint to go play in a clothes dryer.

Alternatively, you could try this instead:

if not is_integer(${var3}) or (${var3} < 0) {
  validate_re( ${var3}, '[0-9]+')
}


John

[Brian Mathis]

I have decided to exclude these files from that puppet-lint test, so I can use double-quotes only.  However, if validate_re() is expecting to only operate on a string, it should be doing this internally and not forcing it upon the user to make an explicit cast to a string.  This is a bug in validate_re(), even though there is a workaround.

❧ Brian Mathis

@orev

[Felix Frank]

On 05/20/2014 07:16 PM, Brian Mathis wrote:
> This is a bug in validate_re(), even though there is a workaround.

Arguably so.

One could also argue, on the other hand, that regular expressions are
matched by *strings* and nothing else. Sure, we've been spoiled by bash
and perl which don't give damn and implicitly convert to string every
chance they get. But that isn't a universal truth. Point in fact

irb(main):001:0> puts "it works!" if 5 =~ /[0-9]+/
=> nil

I agree that it *is* inconvenient to check for two cases "is numeric" or
"contains a number" when logically the former implies the latter. I also
think that implicit string conversion would be a beneficial feature for
validate_re. But it is not necessarily a bug.

Cheers,
Felix

[Brian Mathis]

If validate_re() is only effective on strings, then, in a dynamically typed language such as ruby/puppet, it better make sure it's casting to a string inside the function.  Forcing the use of quotes is a workaround for something that it should be doing and creates inconsistency in the interface.  Forcing the user to be aware of the internals of the function in order to use it defeats the point of using functions.

One of the big problems here is that sometimes it works and sometimes it doesn't for the same data, depending on where you got it and what you did with it, which is clearly a bug.  I'm not sure how else you can define a bug other than "actual behavior does not match expected behavior", when the expectation is merely that the function performs in a predictable way.

❧ Brian Mathis

@orev

[Robin Bowes]

I thought hiera always returns strings? ie. $myvar = hiera('testvalue') should return a string, and validate_re( $myvar, '[0-9]+' ) should work just fine?

Regardless, this is inconsistent:

OK:
       $var = 1000
       validate_re( $var, '[0-9+]' )

FAIL:
       $var2 = 2000 + 1
       validate_re( $var2, '[0-9+]' )

In the first case, the number is cast as a string. In the second, it is not.

The inconsistency makes this a bug, IMHO.

R.

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