ytt fmt does not handle percentage signs

[epk]

What steps did you take:

$ cat test.yaml               
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    name: jobs-low-2
    type: jobs
  name: jobs-low-2
spec:
  progressDeadlineSeconds: 900
  revisionHistoryLimit: 10
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 0
      maxUnavailable: 25%

$ cat test.yaml | ytt fmt -f -
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    name: jobs-low-2
    type: jobs
  name: jobs-low-2
spec:
  progressDeadlineSeconds: 900
  revisionHistoryLimit: 10
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 0
      maxUnavailable: 25%!(NOVERB)

What happened:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    name: jobs-low-2
    type: jobs
  name: jobs-low-2
spec:
  progressDeadlineSeconds: 900
  revisionHistoryLimit: 10
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 0
      maxUnavailable: 25%!(NOVERB) <- ???

What did you expect:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    name: jobs-low-2
    type: jobs
  name: jobs-low-2
spec:
  progressDeadlineSeconds: 900
  revisionHistoryLimit: 10
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 0
      maxUnavailable: 25%

Anything else you would like to add:

I think we are not properly escaping % in the parser

Environment:

• ytt version (use ytt --version): ytt version 0.32.0

• OS (e.g. from /etc/os-release): macOS 11.2.3 (20D91)

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[pivotaljohn]

Thanks for reporting this bug, @epk.

To be clear, the %!(NOVERB) is output from fmt.Fprintf(). Which indicates that we're passing the raw string to that function without escaping the %, first, as @epk said.

Note that we're doing the proper handling in the template command:

$ ytt -f test.yml
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    name: jobs-low-2
    type: jobs
  name: jobs-low-2
spec:
  progressDeadlineSeconds: 900
  revisionHistoryLimit: 10
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 0
      maxUnavailable: 25%

[aaronshurley]

This feels like a reasonable good first issue to me. @pivotaljohn please correct this if I'm wrong.

We're going to move this to our Unprioritized Backlog at the moment but are open to PRs!

[cari-lynn]

Available in v0.38.0