createCommitOnBranch error example

demo.sh

#!/usr/bin/env sh
set -euo pipefail

# This is an example of intentionally generating an error message from the
# `createCommitOnBranch` mutation by passing an out of date `expectedHeadOid`
# value. Run this inside a git repository configured with a github remote.
# Ensure TOKEN is set to a Personal Access Token with write access to the given
# github repo.
#
# (This script assumes jq is installed for pretty-printing the response JSON)
#
# For more info on using the mutation see the documentation at:
#  - https://docs.github.com/en/graphql/reference/mutations#createcommitonbranch
#  - https://docs.github.com/en/graphql/reference/input-objects#createcommitonbranchinput

remote=`git remote |head -1`
repoNwo=`git remote get-url $remote | sed 's/.*://;s/\.git//'`
branch=`git rev-parse --abbrev-ref HEAD`
contents=`echo -e 'Hello, GraphQL!\n' | base64`

# note, we are *intentionally* telling the API to append a commit to the branch
# only if the tip is a value that we know it is not.  Assuming this clone is up to
# date with the remote this will always fail with a descriptive error.
expectedHeadOid=`git rev-parse HEAD~`

curl https://api.github.com/graphql --silent \
     \ # echo HTTP status to demonstrate how GraphQL
     \ # uses HTTP a mere RPC transport, response is 200 OK
     \ # no matter what errors happen.
     --write-out '%{stderr}HTTP status: %{response_code}\n\n'
     -H "Authorization: bearer $TOKEN" \
     --data @- <<GRAPHQL | jq
{
  "query": "mutation (\$input: CreateCommitOnBranchInput!) {
    createCommitOnBranch(input: \$input) { 
      commit { 
        url 
      } 
    } 
  }",
  "variables": {
    "input": {
      "branch": {
        "repositoryNameWithOwner": "$repoNwo",
        "branchName": "$branch"
      },
      "message": { "headline": "Hello from GraphQL! 😍" },
      "fileChanges": {
        "additions": [
          {
            "path": "GraphQL.md",
            "contents": "$contents"
          }
        ]
      },
      "expectedHeadOid": "$expectedHeadOid"
    }
  }
}
GRAPHQL

output.yaml

# $ ./demo.sh
# HTTP status: 200
{
  "data": {
    "createCommitOnBranch": null
  },
  "errors": [
    {
      "type": "STALE_DATA",
      "path": [
        "createCommitOnBranch"
      ],
      "locations": [
        {
          "line": 1,
          "column": 52
        }
      ],
      "message": "Expected branch to point to \"f786b7e2e0ec290972a2ada6858217ba16305933\" but it did not.  Pull and try again."
    }
  ]
}