[ActivityTrigger] parameter named "data" causes error on local startup

[dlyall-maine]

Here's the method:

    [FunctionName(nameof(DoActivity))]
    public static async Task<string> DoActivity([ActivityTrigger]string data, ILogger log)
    {
        log.LogInformation($"hashing {data}");

        return data.GetHashCode().ToString();
    }

Here's the error that appears in the console window:

[7/20/2019 6:01:27 PM] Microsoft.Azure.WebJobs.Host: Error indexing method 'DoActivity'. Microsoft.Azure.WebJobs.Host: Can't bind parameter 'data' to type 'System.String'.
[7/20/2019 6:01:27 PM] Error indexing method 'DoActivity'
[7/20/2019 6:01:27 PM] Microsoft.Azure.WebJobs.Host: Error indexing method 'DoActivity'. Microsoft.Azure.WebJobs.Host: Can't bind parameter 'data' to type 'System.String'.

When parameter "data" is renamed to, say, "info" the error goes away.

[ColbyTresness]

@jeffhollan

[alexis-franche]

Had the exact same issue with the parameter named "data" in Python 3.8, changed it to something else and it worked. Thank you.

[kwaazaar]

So I've just been troubleshooting this same issue, researching different kind of reasons. But not expecting the parameter name to be the issue! This really needs a fix or a compile (or runtime) error, guys! 😢

[johankson]

Spent a day troubleshooting this... It's never where you think it is.... Please just add a better error message.

[aressler38]

@cgillum

[cgillum]

Removing Jeff from the assignment. @anirudhgarg @mathewc what's the right way to triage this issue? It's an error message generated by the Functions host (not sure if it's Functions or WebJobs) that's impacting Durable Functions customers.

Related: Azure/azure-functions-durable-extension#1062.

[mathewc]

@cgillum The fact that your binding has a "data" member as part of the BindingContract shouldn't cause the trigger parameter to fail binding. I just tried to repro with QueueTrigger which has a contract member DequeueCount here. I'm able to use that name for the trigger binding no problem:

public void ProcessMessage([QueueTrigger("test")] string dequeueCount, ILogger logger)

Perhaps there is something unique with the Durable extension. Does it only happen in Functions, or outside of functions as well? Would be good to debug a minimal repro locally to find out exactly why/where your binding is failing indexing.

[kerrpeter]

I had a similar issue with a HttpTrigger function, and posting a object. If the object had a property the same name as the object variable name, it raised this error - very weird

eg here we have post variable of type SaveContactPref call contactPref
public async Task<IActionResult> SaveUserContactPref([HttpTrigger(AuthorizationLevel.Anonymous, "post", Route = null)] SaveContactPref contactPref, ClaimsPrincipal claimIdentity)
If the SaveContactPref has a property called "ContactPref", this error is raised. If I rename the property, its all ok

[csfinlayson]

4 years after the initial issue was raised this still exists and like other commenters I wasted time chasing this bug. Echo others in saying please mention that "data" is reserved in documentation and/or provide a more meaningful error message.

[recumbented]

I can't understand that this issue still exists.
I strongly hope fix shortly.

[kevinhillinger]

2024, issue hasn't been documented. Came across this today with durable functions chaining. luckily this issue existed so that I knew to change the name of the parameter, otherwise I would have been spinning my wheels.

[gimmi]

Same problem for me.

That issue is embarassing...