1557176 - fix kvstore Clippy warning: `if _ { .. } else { .. }` is an expression

Status: RESOLVED FIXED

(Toolkit :: Storage, enhancement)

Description

[Myk Melez [:myk] [@mykmelez]]

It's tricky to run Clippy on Rust crates in mozilla-central, but it's possible to do so for some of them via a specific sequence of cargo invocations; and when I do that for kvstore:

cargo clean && cargo check -p kvstore && touch toolkit/components/kvstore/src/lib.rs && cargo clippy -p kvstore

Then Clippy reports this warning:

warning: `if _ { .. } else { .. }` is an expression
   --> toolkit/components/kvstore/src/task.rs:135:5
    |
135 | /     let size;
136 | |
137 | |     if current_size < INCREMENTAL_RESIZE_THRESHOLD {
138 | |         size = current_size << 1;
139 | |     } else {
140 | |         size = current_size + INCREMENTAL_RESIZE_STEP;
141 | |     }
    | |_____^ help: it is more idiomatic to write: `let size = if current_size < INCREMENTAL_RESIZE_THRESHOLD { current_size << 1 } else { current_size + INCREMENTAL_RESIZE_STEP };`
    |
    = note: #[warn(clippy::useless_let_if_seq)] on by default
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_let_if_seq

Comment 1

[Nan Jiang [:nanj]]

Attachment: Bug 1557176 - Clippy fix for kvstore

Comment 2

[Nan Jiang [:nanj]]

Nice tip! Thanks!

Hmm, looks like I have to set some environment variables to run that command, it yelled at me with environment variable 'MOZ_TOPOBJDIR' not defined.

Comment 3

[Myk Melez [:myk] [@mykmelez]]

(In reply to Nan Jiang [:nanj] from comment #2)

Hmm, looks like I have to set some environment variables to run that command, it yelled at me with environment variable 'MOZ_TOPOBJDIR' not defined.

Ah, right, I forgot that I have that set by default in my environment. (Some other crates that depend on servo have additional requirements that I haven't been able to figure out how to satisfy yet.)

Comment 4

[Lina Butler [:lina]]

Nifty! I've used env MOZ_TOPOBJDIR=$HOME/Code/gecko/obj-fx-debug cargo fmt locally, too, it's nice that Clippy works now!

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a30adf37aef0
Clippy fix for kvstore r=myk

Comment 6

[Daniel Varga [:dvarga]]

https://hg.mozilla.org/mozilla-central/rev/a30adf37aef0