[yew-devel] [RFC PATCH] store: use try_borrow and expect_throw for better error messages

[Dominik Csapak]

high level question/comment:

AFAIU you want to add proper error messages to the borrows here,
so wouldn't it be enough to use 'try_borrow().expect("some error")' ?

or does the UnrwapThrowExt trait something additional that we want/need which
I'm overlooking?

E.g. in PDM we have a global panic hook that displays the panic (and i think stack trace)

and the default panic hook logs it into the console
(which also happens for uncaught exceptions)

On 5/5/25 15:28, Shannon Sterz wrote:
> this makes use of the `UnwrapThrowExt` trait to improve error messages
> when acquring store locks. taking such locks in async functions can
> sometimes lead to bugs that can be unreliably reproduced, this should
> provide more information about the source of the error compared to
> just panicking.
> 
> Signed-off-by: Shannon Sterz <s.sterz at proxmox.com>
> ---
> 
> alternatively we could return the error here directly (or wrap it) and
> let the call site handle such errors. however, that would require
> breaking this public api, so i decided against this for now.
> 
>   src/state/store.rs | 13 +++++++++++--
>   1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/src/state/store.rs b/src/state/store.rs
> index bde7d9da..b071182c 100644
> --- a/src/state/store.rs
> +++ b/src/state/store.rs
> @@ -10,6 +10,8 @@ use yew::html::IntoEventCallback;
>   use yew::prelude::*;
>   use yew::virtual_dom::Key;
> 
> +use wasm_bindgen::UnwrapThrowExt;
> +
>   use crate::props::{
>       ExtractKeyFn, ExtractPrimaryKey, FilterFn, IntoFilterFn, IntoSorterFn, SorterFn,
>   };
> @@ -130,7 +132,10 @@ impl<T: 'static> Store<T> {
>       /// Panics if the value is currently mutably locked.
>       pub fn read(&self) -> StoreReadGuard<T> {
>           StoreReadGuard {
> -            state: self.inner.borrow(),
> +            state: self
> +                .inner
> +                .try_borrow()
> +                .expect_throw("Could not acquire read lock on store!"),
>           }
>       }
> 
> @@ -142,7 +147,11 @@ impl<T: 'static> Store<T> {
>       /// When the returned [StoreWriteGuard] is dropped, the store listeners
>       /// are notified. To prevent that use [StoreWriteGuard::skip_update]
>       pub fn write(&self) -> StoreWriteGuard<T> {
> -        let state = self.inner.borrow_mut();
> +        let state = self
> +            .inner
> +            .try_borrow_mut()
> +            .expect_throw("Could not acquire write lock on store!");
> +
>           StoreWriteGuard {
>               state,
>               update: true,
> --
> 2.39.5
> 
> 
> 
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