Manual triggering of DAG with object Param having empty default value fails

[vikmary]

Apache Airflow version

2.10.5

If "Other Airflow 2 version" selected, which one?

No response

What happened?

If a DAG contains "object" Param having valid empty dictionary {} as default, then the manual triggering for it doesn't succeed. In this case, If I push "Trigger" button in UI, it just doesn't react.

What you think should happen instead?

The DAG should trigger with Param having {} value.

How to reproduce

from airflow import DAG                                                                                                                                                                                                                                   
from airflow.operators.dummy import DummyOperator                                                                                                                                                                                                         
from airflow.models import Param                                                                                                                                                                                                                          
                                                                                                                              
with DAG(                                                                                                                                                                                                                                                 
    "run-test",                                                                                                                                                                                                                                           
    params={                                                                                                                                                                                                                                              
        "object_param": Param({}, type="object", description="Object field"),                                                                                                                                                                                                                                                
    },                                                                                                                                                                                                                                                    
    schedule=None,                                                                                                                                                                                                                                        
    catchup=False,                                                                                                                                                                                                                                        
 ) as dag:                                                                                                                                                                                                                                                 
    DummyOperator(task_id="dummy_task")   

Operating System

Ubuntu 22.04.4 LTS

Versions of Apache Airflow Providers

apache-airflow-providers-common-compat==1.3.0
apache-airflow-providers-common-io==1.5.0
apache-airflow-providers-common-sql==1.21.0
apache-airflow-providers-fab==1.5.2
apache-airflow-providers-ftp==3.12.0
apache-airflow-providers-http==5.0.0
apache-airflow-providers-imap==3.8.0
apache-airflow-providers-smtp==1.9.0
apache-airflow-providers-sqlite==4.0.0

Deployment

Virtualenv installation

Deployment details

Installation and setup script

#!/bin/bash

set -ex

AIRFLOW_HOME=~/airflow
ENV_NAME=airflow-env

function install_python {
    apt-get update
    apt-get -y install python3.10 python3.10-venv
}

function create_virtualenv {
    python3.10 -m venv $ENV_NAME
    source $ENV_NAME/bin/activate
    pip install --upgrade pip
    pip install apache-airflow==2.10.5 --constraint "https://raw.githubusercontent.com/apache/airflow/constraints-2.10.5/constraints-3.10.txt"
}

function configure_airflow {
    export AIRFLOW_HOME=$AIRFLOW_HOME
    export AIRFLOW__CORE__DAGS_FOLDER=./pipelines
    export AIRFLOW__CORE__LOAD_EXAMPLES=False
    export AIRFLOW__DATABASE__LOAD_DEFAULT_CONNECTIONS=False
    airflow config list > "${AIRFLOW_HOME}/airflow.cfg"
}

mkdir -p $AIRFLOW_HOME
cd $AIRFLOW_HOME

install_python
create_virtualenv
configure_airflow

airflow standalone

Anything else?

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[boring-cyborg]

Thanks for opening your first issue here! Be sure to follow the issue template! If you are willing to raise PR to address this issue please do so, no need to wait for approval.

[vikmary]

If I change parameter to

    params={                                                                                                                                                                                                                                              
        "object_param": Param(None, type=["null", "object"], description="Object field"),                                                                                                                                                                                                                                                
    }, 

or to

    params={                                                                                                                                                                                                                                              
        "object_param": Param({"a": "1"}, type="object", description="Object field"),                                                                                                                                                                                                                                                
    }, 

then it works.

But the version from the issue text worked ok in earlier Airflow versions.

[vikmary]

Might be connected to #45313

[vikmary]

@jscheffl Do you possibly see a fix?

[vikmary]

{} and None are not the same. So in case of no overriding I would expect

    params={                                                                                                                                                                                                                                              
        "object_param": Param(None, type=["null", "object"], description="Object field"),                                                                                                                                                                                                                                                
    }, 

to result in object_param equaling None and

    params={                                                                                                                                                                                                                                              
        "object_param": Param({}, type=["null", "object"], description="Object field"),                                                                                                                                                                                                                                                
    }, 

or

        "object_param": Param({}, type="object", description="Object field"),                                                                                                                                                                                                                                                
    }, 

to result in object_param equaling empty dictionary {}.

[vikmary]

FYI: reversing changes made by PR above to airflow/www/templates/airflow/trigger.html fixes my case. But I'm not sure whether this is the best fix possible

[jscheffl]

I would assume the case with {} is fixed in next version via #46872
Feel free to patch locally and test.

[vikmary]

It does fix it, a big thank you!