pyyaml yaml.load returns str instead of dict

Question

Using pyyaml and python3, the following in-memory yaml string loads without error but yaml.full_load() returns a str and not a dict. Is this expected behavior? Thanks.

main:
  orgs:
    &org1 org1:
      categories:
        - one
        - two
        - three
    &org2 org2:
      categories:
        - one
        - two
  people:
    - userid: user1
      org: *org1
      roles:
        - roleA
        - roleB
    - userid: user2
      org: *org2
      roles:
        - roleA

print("MAIN_YAML = " + os.getenv("MAIN_YAML"))

try:
    MAIN_YAML = yaml.full_load(os.getenv("MAIN_YAML"))
    print("PARSED SUCCESSFULLY")
    print(isinstance(MAIN_YAML, dict))
    print(type(MAIN_YAML))
except (yaml.YAMLError, yaml.YAMLLoadWarning) as e:
    print(e)

MAIN_YAML = main:orgs:&org1org1:categories:-one-two-three&org2org2:categories:-one-twopeople:-userid:user1org:*org1roles:-roleA-roleB-userid:user2org:*org2roles:-roleA
PARSED SUCCESSFULLY
False
<class 'str'>

Here's the shell script that creates the one-liner:

tr -d '\n\t' < main.yaml > temp.yaml
tr -d ' ' < temp.yaml > main_squeezed.yaml
MAIN_YAML=$(cat main_squeezed.yaml)

Answer 1

It appears you're loading it from an environment variable which doesn't have the YAML file "as is" (with newline characters).

It works when the string has the newline characters included:

>>> s = """main:
...   orgs:
...     &org1 org1:
...       categories:
...         - one
...         - two
...         - three
...     &org2 org2:
...       categories:
...         - one
...         - two
...   people:
...     - userid: user1
...       org: *org1
...       roles:
...         - roleA
...         - roleB
...     - userid: user2
...       org: *org2
...       roles:
...         - roleA"""
>>>
>>> import yaml
>>> yaml.full_load(s)
{'main': {'orgs': {'org1': {'categories': ['one', 'two', 'three']}, 'org2': {'categories': ['one', 'two']}}, 'people': [{'userid': 'user1', 'org': 'org1', 'roles': ['roleA', 'roleB']}, {'userid': 'user2', 'org': 'org2', 'roles': ['roleA']}]}}

It doesn't work when the string is one line of text:

>>> t = s.replace('\n', '').replace(' ', '')  # same thing, but one line
>>> yaml.full_load(t)
'main:orgs:&org1org1:categories:-one-two-three&org2org2:categories:-one-twopeople:-userid:user1org:*org1roles:-roleA-roleB-userid:user2org:*org2roles:-roleA'