[BUG] Dispatch actions fail when modal has been updated with client.views.update

[Aze331]

The deno-slack versions

"deno-slack-sdk/": "https://deno.land/x/[email protected]/",
"deno-slack-api/": "https://deno.land/x/[email protected]/"

Deno runtime version

deno 2.2.3 (stable, release, x86_64-pc-windows-msvc)
v8 13.4.114.11-rusty
typescript 5.7.3

OS info
Microsoft Windows [Version 10.0.19045.5487]

Describe the bug

When a modal is opened using client.views.open, the modal displays correctly. However, after the modal is updated via client.views.update to include interactive elements (with dispatch_action: true), these elements do not trigger any block action events when interacted with. Although the updated modal renders without errors, user interactions (e.g. selecting a user in a users select element) produce no event payloads, and Slack logs no detailed errors.

Steps to reproduce

1. Create a basic Slack app using the deno-slack-sdk.
2. Open a modal using client.views.open and output the returned view ID and hash.
3. Update the modal view via client.views.update, ensuring that interactive elements (with dispatch_action: true) are present in the updated view.
4. Interact with one of the interactive elements in the updated modal.
5. Observe that no block action payload is received by the handler—the UI briefly shows a loading spinner, then displays an error icon—while no error messages or logs are produced by Slack.

Expected result

Interactive elements in the updated modal should trigger block action events, and the registered action handlers (via addBlockActionsHandler or addViewSubmissionHandler) should receive the interactive payload.

Actual result

After the modal is updated with client.views.update, interactive elements do not dispatch any events. The modal appears unresponsive to user interactions even though all interactive properties (e.g. dispatch_action: true) are present. No error messages or payload logs are received from Slack.

import { DefineFunction, Schema, SlackFunction } from "deno-slack-sdk/mod.ts";

// Function to open a modal
export const FetchFunctionDefinition = DefineFunction({
  callback_id: "fetch-modal",
  title: "Fetch modal",
  source_file: "functions/fetch_modal.ts",
  input_parameters: {
    properties: { interactivity: { type: Schema.slack.types.interactivity } },
    required: ["interactivity"],
  },
  output_parameters: {
    properties: {
      view_id: { type: Schema.types.string },
      hash: { type: Schema.types.string },
    },
    required: ["view_id", "hash"],
  },
});

export default SlackFunction(
  FetchFunctionDefinition,
  async ({ inputs, client }) => {
    const { interactivity: { interactivity_pointer: trigger_id } } = inputs;
    const resp = await client.views.open({
      trigger_id,
      view: {
        type: "modal",
        callback_id: "fetch_modal",
        title: { type: "plain_text", text: "Fetching information" },
        blocks: [{
          type: "section",
          text: {
            type: "plain_text",
            text: "Fetching information. Please wait...",
          },
        }],
      },
    });
    return {
      outputs: { view_id: resp.view.id, hash: resp.view.hash },
    };
  },
);

// Function to update the modal with an interactive element that uses dispatch_action
export const UpdateFunctionDefinition = DefineFunction({
  callback_id: "update-modal",
  title: "Update modal",
  source_file: "functions/update_modal.ts",
  input_parameters: {
    properties: {
      view_id: { type: Schema.types.string },
      hash: { type: Schema.types.string },
    },
    required: ["view_id", "hash"],
  },
});

export default SlackFunction(
  UpdateFunctionDefinition,
  async ({ inputs, client }) => {
    const { view_id: viewId, hash } = inputs;
    await client.views.update({
      view_id: viewId,
      hash: hash,
      view: {
        type: "modal",
        callback_id: "update_modal",
        submit: { type: "plain_text", text: "Update" },
        close: { type: "plain_text", text: "Close" },
        title: { type: "plain_text", text: "Update" },
        blocks: [
          {
            type: "section",
            block_id: "role_block",
            text: { type: "mrkdwn", text: "Select a user:" },
            accessory: {
              type: "users_select",
              action_id: "role_action",
              dispatch_action: true,
            },
          },
        ],
      },
    });
    return { completed: false };
  },
)
.addBlockActionsHandler(["role_action"], async ({ action }) => {
  console.log("Incoming action handler invocation", action);
});

[Aze331]

For context, the intended workflow is to use an initial modal step to capture an interaction payload and open a placeholder modal to avoid timing out. In a subsequent step, values are fetched from a datastore (or similar source) and then used to update the modal view with pre-filled input values. Up to that point, everything works fine and the view is updated as expected. However, once the modal is updated via client.views.update, any interaction with the updated input elements (e.g., user selects) fails to trigger any response.

I reviewed the documentation and couldn’t find any specific notes on this behavior. I suspect that updating the view on its own—without a fresh user interaction—might be causing Slack to “use up” the initial interactivity payload, leading to subsequent dispatch actions not being recognized.

[misscoded]

Hi @Aze331 - thanks for bringing this to our attention! The team's been out this week for a conference, so give us some time to look into reproducing this and we'll get back to you with a proper response. 🙂