ytt converts floating point numbers to integers

[maxwell-k]

What steps did you take:

ytt appears to convert input floats to integers, for example, running the command below:

  echo 1.0 | ytt --file=-

I am passing ytt a single floating point number - 1.0 - encoded as YAML.

What happened:

The output from ytt is an integer:

1

What did you expect:

I expected the output to be a float:

1.0

Anything else you would like to add:

I understand that integer and floating point data types differ in the YAML spec. This is a simplified example from input to an application. That application behaves differently if its YAML input contains an integer or a float. In the actual use case these numbers are embedded inside more complex structures.

Environment:

Version:

% ytt --version
 ytt version 0.45.0

OS Fedora Linux 26 on AMD 64.

/etc/os-release

NAME="Fedora Linux"
VERSION="36 (Workstation Edition)"
ID=fedora
VERSION_ID=36
VERSION_CODENAME=""
PLATFORM_ID="platform:f36"
PRETTY_NAME="Fedora Linux 36 (Workstation Edition)"
ANSI_COLOR="0;38;2;60;110;180"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:36"
HOME_URL="https://fedoraproject.org/"
DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f36/system-administrators-guide/"
SUPPORT_URL="https://ask.fedoraproject.org/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=36
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=36
PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
SUPPORT_END=2023-05-16
VARIANT="Workstation Edition"
VARIANT_ID=workstation

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[100mik]

There seems to have been prior discussion on this as well on this slack thread. And is actually related to how the yaml.v2 library we use to marshal our YAML treats floating points, a user had previously created an issue related to this here.

The key thoughts that would be worth capturing here as well would be:

1. "In 1.2.2 yaml, floating regex seems to have changed again making .X optional", which should mean that the YAML value can be loaded as a float even if its missing .X
2. "So if an application is behaving in a different way when someone enters "42" or "42.0", that sounds like a bug worth fixing in the application."
   • Is the consumer of ytts output unable to differentiate between these two values in your case?

I ran a few cases real quick through ytt, to see how the language behaves if we drop the .X and ytt seems to be able to realise when a float-like representation is required.

Input:

a: #@ 1.0
b: #@ 1.1
c: #@ 1.0 + 2
d: #@ 1.0 + 1.1
e: #@ 2.0 * 2.1

Output:

a: 1
b: 1.1
c: 3
d: 2.1
e: 4.2