Binding store value to a component evokes all callbacks of all of store's subscribers when the component is created

[pavish]

Describe the bug

Based on the Svelte docs, the callbacks of writable store subscriptions get called on these scenarios:

• writable value changes
• when first subscriber subscribes

However, when we bind a store value to a component, the callbacks get called whenever the component is created, even when the component is not a first subscription to the store.

Reproduction

REPL Link: https://svelte.dev/repl/abb6864f83cc4b7f9a3e84cae74e8dad?version=3.46.4

When the REPL is opened, in the output console, you can notice the two logs:

"first-subscriber"
"names changed" Array(1)[ "value" ]

Try clicking on the 'Toggle' button, you can notice that the text names changed gets logged whenever Component is shown.

If we remove bind:names and pass names={$names}, it does not happen.

Logs

No response

System Info

System:
    OS: Linux 5.10 Ubuntu 20.04.3 LTS (Focal Fossa)
    CPU: (4) arm64 unknown
    Memory: 188.52 MB / 1.94 GB
    Container: Yes
    Shell: 5.0.17 - /bin/bash
  Binaries:
    Node: 14.19.0 - /usr/bin/node
    npm: 6.14.16 - /usr/bin/npm
  npmPackages:
    svelte: ^3.42.4 => 3.42.4

Severity

annoyance

[Prinzhorn]

This is a known issue

#6298
#5689

[bluwy]

Closing as duplicate of the linked issues