schema: tracecback when using schema --annotate on single line dicts

This bug was originally filed in Launchpad as [LP: #1885598](https://bugs.launchpad.net/cloud-init/+bug/1885598)

Launchpad details

affected_projects = []

assignee = None

assignee_name = None

date_closed = None

date_created = 2020-06-29T16:18:15.900486+00:00

date_fix_committed = None

date_fix_released = None

id = 1885598

importance = medium

is_complete = False

lp_url = https://bugs.launchpad.net/cloud-init/+bug/1885598

milestone = None

owner = chad.smith

owner_name = Chad Smith

private = False

status = triaged

submitter = chad.smith

submitter_name = Chad Smith

tags = ['bitsize']

duplicates = []

_Launchpad user **Chad Smith(chad.smith)** wrote on 2020-06-29T16:18:15.900486+00:00_

Annotate doesn't handle r-value dicts that begin on the same line as the l-value key.

Given the following example invalid cloudconfig (providing an int for a string value in chef), we get a traceback when trying to annotate the invalid user-data.

cat > invalid-chef-traceback.yaml < invalid-chef.yaml <
return_value = main(sys.argv)
File "/home/csmith/src/cloud-init/cloudinit/cmd/main.py", line 891, in main
retval = util.log_time(
File "/home/csmith/src/cloud-init/cloudinit/util.py", line 2285, in log_time
ret = func(*args, **kwargs)
File "/home/csmith/src/cloud-init/cloudinit/config/schema.py", line 444, in handle_schema_args
validate_cloudconfig_file(
File "/home/csmith/src/cloud-init/cloudinit/config/schema.py", line 219, in validate_cloudconfig_file
print(annotated_cloudconfig_file(
File "/home/csmith/src/cloud-init/cloudinit/config/schema.py", line 151, in annotated_cloudconfig_file
errors_by_line[schemapaths[path]].append(msg)
KeyError: 'chef.install_type'

Start in cloudinit/config/schema.py, especially annotated_cloudconfig_file and the schema command path shown in the traceback. Reproduce the issue with a single-line dict such as chef: {install_type: 1}, then verify that devel schema --annotate reports the validation error without raising a KeyError.

Written by the indexing model from the issue text.