Enabled required features from examples automatically #636

DaAlbrecht · 2025-10-06T19:49:47Z

Objective

Enable the required features from examples automatically. If all examples should be built/checked, enable --all-features.

Testing

❯ bevy run --example web_asset -v
debug: running: `cargo metadata --format-version 1`
debug: enabling required_features: ["https"], for example: web_asset
debug: running: `cargo run --example web_asset --features https --profile dev`
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.14s

❯ bevy build --example web_asset -v
debug: running: `cargo metadata --format-version 1`
debug: enabling required_features: ["https"], for example: web_asset
debug: running: `cargo build --example web_asset --features https --profile dev`
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.14s

Note

Building and lining all examples does not work until #629

Closes #622

alice-i-cecile · 2025-10-06T19:53:58Z

Yay! That's very nice.

BD103

I haven't had a chance to look over the code yet, but could you please add some basic docs on this feature? I don't want to diverge from Cargo without documenting it :)

DaAlbrecht · 2025-10-06T20:13:13Z

I haven't had a chance to look over the code yet, but could you please add some basic docs on this feature? I don't want to diverge from Cargo without documenting it :)

yea good point! Alice mentioned she would like a yes/no prompt i think that would be self documenting and no longer silently diverge from cargo what do you think?

BD103 · 2025-10-07T00:58:25Z

yea good point! Alice mentioned she would like a yes/no prompt i think that would be self documenting and no longer silently diverge from cargo what do you think?

While I think a prompt would be good with users who are unaware of the feature, I think it would also be really annoying for users who are aware and actively want the example's required features to be enabled. Maybe a good alternative would be switching the enabling required_features log message from debug!() to info!()?

But I also don't think that replaces having documentation on our website. A user shouldn't have to install the CLI or read the changelog to see all the features supported by a program. I can draft up something if you want me to!

DaAlbrecht · 2025-10-07T17:25:35Z

I can draft up something if you want me to!

I added a section but I always appreciate your docs/writing style, so feel free to delete it ^^

BD103

Very good, the implementation is especially clean after #622 was merged!

BD103 · 2026-02-10T03:27:30Z

src/commands/build/mod.rs

+        args.cargo_args
+            .feature_args
+            .features
+            .push("--all-features".to_owned());
+
+        info!("automatically added `--all-features` to build examples with all features enabled");


I'm not sure we should always enable --all-features when --examples is passed. When I run cargo build --examples --all-features in Bevy's repo, it fails with a compile error. That's not a great user experience, especially when the primary use of this feature will be by Bevy devs.

In @alice-i-cecile's original comment when I asked how to deal with --examples and --all-targets, she said:

Based on the design proposed in the linked issue, I would build these with --all-features (uh, except where mutually incompatible features exist) and diverge from cargo. Or at least warn users that they probably want to enable all the features and try again.

I think we either need to be more intelligent with how we handle mutually incompatible features, or just cut this for now. The alternative is Bevy devs being unable to compile the Bevy workspace with bevy build --examples, having to switch to cargo build --examples, which I don't think is acceptable.

If we update this, make sure to also update the section in examples.md and lint/mod.rs.

BD103 · 2026-02-10T03:29:42Z

docs/src/cli/index.md

 - [**Build and running Bevy Web Apps**](web.md)
 - [**Linter Integration**](linter.md)
+- [**Enabling required features for examples**](examples.md)


Suggested change

- [**Build and running Bevy Web Apps**](web.md)

- [**Linter Integration**](linter.md)

- [**Enabling required features for examples**](examples.md)

- [**Build and Running Bevy Web Apps**](web.md)

- [**Linter Integration**](linter.md)

- [**Enabling Required Features for Examples**](examples.md)

(Nit) Let's make all of these title case

BD103 · 2026-02-10T03:38:35Z

docs/src/cli/examples.md

+```sh
+# Run the `web_asset` example from https://github.com/bevyengine/bevy that requires the feature `https`.
+bevy run --example web_asset
+info: enabling required_features: ["https"], for example: web_asset
+
+# Build the `web_asset` example in the web.
+bevy build --example web_asset web
+info: enabling required_features: ["https"], for example: web_asset
+```


Suggested change

```sh

# Run the `web_asset` example from https://github.com/bevyengine/bevy that requires the feature `https`.

bevy run --example web_asset

info: enabling required_features: ["https"], for example: web_asset

# Build the `web_asset` example in the web.

bevy build --example web_asset web

info: enabling required_features: ["https"], for example: web_asset

```

Take Bevy's `web_asset` example, for instance. It requires the `https` feature in `Cargo.toml`:

```toml

[[example]]

name = "web_asset"

path = "examples/asset/web_asset.rs"

required-features = ["https"]

```

Running `cargo build --example web_asset` will fail with Cargo complaining that the `https` feature was not enabled. The Bevy CLI differs by automatically enabling the feature for you:

```sh

# The CLI will automatically add `--feature https`, as that feature is required to run the example.

bevy run --example web_asset

# It also works when building for the web.

bevy build --example web_asset web

```

I think it would be good to show how required features are specified in Cargo.toml :)

feat: enabled required features from examples by default

b884403

DaAlbrecht added A-Run Related to the bevy run command A-Build Related to the bevy build command D-Straightforward Simple bug fixes and API improvements, docs, test and examples S-Needs-Review The PR needs to be reviewed before it can be merged labels Oct 6, 2025

alice-i-cecile mentioned this pull request Oct 6, 2025

Automatically enable required-features rust-lang/cargo#4663

Open

feat: log enabling --all-features to build all examples

f21dc30

alice-i-cecile approved these changes Oct 6, 2025

View reviewed changes

BD103 reviewed Oct 6, 2025

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DaAlbrecht and others added 3 commits October 7, 2025 19:01

feat: switch from debug level to info

0a1a9bf

doc: add section to mdbook

5d06df4

Merge branch 'main' into set-features-for-examples-622

f31d3f4

DaAlbrecht and others added 2 commits November 9, 2025 10:18

Merge branch 'main' into set-features-for-examples-622

91e3205

Merge branch 'main' into set-features-for-examples-622

f86a10e

BD103 reviewed Feb 10, 2026

View reviewed changes

BD103 added S-Waiting-on-Author The author needs to make changes or address concerns before this can be merged and removed S-Needs-Review The PR needs to be reviewed before it can be merged labels Feb 10, 2026

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Enabled required features from examples automatically #636

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Objective

Testing

Note

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