please preserve leading whitespace after the ytt inline-code token

[dreftymac]

Overview

• indentation_preserve_request
• ytt version 0.45.0

Problem

• ytt processing does not preserve leading whitespace for #@ expressions
• ytt appears to remove all whitespace after the #@ when evaluating ytt-enhanced YAML

Example

• consider the following well-formed ytt YAML document
• we use a ytt function to output a variable
• we use ytt #@ expressions to specify inline python/starlark code inside the function
• we define a multiline string variable str_multiline
• we then assign the function result to yaml data output

## -------------------------------------------------------------------
## begin_ ytt.functions

#@ def feature_request_preserve_indentation():
  #@ str_multiline = ('''
  #@  charlie_info:
  #@    charlie_one:    111
  #@    charlie_two:    222
  #@    charlie_three:  333
  #@  delta_info:
  #@    delta_one:      111
  #@    delta_two:      222
  #@    delta_three:    333
  #@  echo_info:
  #@    echo_one:       111
  #@    echo_two:       222
  #@    echo_three:     333
  #@ ''')
  #@ return(str_multiline)
#@ end

## -------------------------------------------------------------------
## begin_ yaml data output

dataroot:
  demo_string: #@ feature_request_preserve_indentation()

Results

• we do not want the undesirable result BEFORE
• instead, we want the desirable result AFTER

Non desired result -- BEFORE

dataroot:
  demo_string: |2

    charlie_info:
    charlie_one:    111
    charlie_two:    222
    charlie_three:  333
    delta_info:
    delta_one:      111
    delta_two:      222
    delta_three:    333
    echo_info:
    echo_one:       111
    echo_two:       222
    echo_three:     333

Yes desired result -- AFTER

dataroot:
  demo_string: |
    charlie_info:
      charlie_one:    111
      charlie_two:    222
      charlie_three:  333
    delta_info:
      delta_one:      111
      delta_two:      222
      delta_three:    333
    echo_info:
      echo_one:       111
      echo_two:       222
      echo_three:     333

Feature request

• please allow ytt code regions to preserve leading whitespace that appears after the #@ token

Rationale

• sometimes whitespace is significant (as in this example where the #@ token is used for a multiline string variable
• the current parsing strategy seems to assume that leading whitespace after the #@ token is not relevant
• this assumption (if correct) limits the kind of code one can deploy using ytt

---

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[github-actions]

This issue is being marked as stale due to a long period of inactivity and will be closed in 5 days if there is no response.

[vmunishwar]

Sorry for the late reply. Thanks for adding this issue. We are able to reproduce this issue. We will analyze this further and get back to you soon.
Thanks for reaching out!