Allow compiling eframe with `--no-default-features` (#2728)

* Check that we can compile eframe with --no-default-features

* Allow compiling eframe with `--no-default-features`

This is useful for libraries that depend on `eframe::Frame`
but don't care what renderer eframe is using.

4 files changed, 48 insertions, 11 deletions

diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 738a2d63..a8d77527 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -47,24 +47,30 @@ jobs:
         with:
           crate: cargo-cranky
 
-      - name: Check all features
+      - name: check --all-features
         uses: actions-rs/cargo@v1
         with:
           command: check
           args: --locked --all-features --all-targets
 
-      - name: Check default features
+      - name: check default features
         uses: actions-rs/cargo@v1
         with:
           command: check
           args: --locked --all-targets
 
-      - name: Check no default features
+      - name: check --no-default-features
         uses: actions-rs/cargo@v1
         with:
           command: check
           args: --locked --no-default-features --lib --all-targets
 
+      - name: check eframe --no-default-features
+        uses: actions-rs/cargo@v1
+        with:
+          command: check
+          args: --locked --no-default-features --lib --all-targets -p eframe
+
       - name: Test doc-tests
         uses: actions-rs/cargo@v1
         with:
diff --git a/crates/eframe/CHANGELOG.md b/crates/eframe/CHANGELOG.md
index b492cf7f..46e1ddd4 100644
--- a/crates/eframe/CHANGELOG.md
+++ b/crates/eframe/CHANGELOG.md
@@ -5,6 +5,7 @@ NOTE: [`egui-winit`](../egui-winit/CHANGELOG.md), [`egui_glium`](../egui_glium/C
 
 
 ## Unreleased
+* Allow compiling with `--no-default-features` ([#2728](https://github.com/emilk/egui/pull/2728)).
 
 
 ## 0.21.1 - 2023-02-12
diff --git a/crates/eframe/src/epi.rs b/crates/eframe/src/epi.rs
index 1c9cb021..31127c02 100644
--- a/crates/eframe/src/epi.rs
+++ b/crates/eframe/src/epi.rs
@@ -10,9 +10,11 @@
 use std::any::Any;
 
 #[cfg(not(target_arch = "wasm32"))]
+#[cfg(any(feature = "glow", feature = "wgpu"))]
 pub use crate::native::run::UserEvent;
 
 #[cfg(not(target_arch = "wasm32"))]
+#[cfg(any(feature = "glow", feature = "wgpu"))]
 pub use winit::event_loop::EventLoopBuilder;
 
 /// Hook into the building of an event loop before it is run
@@ -20,6 +22,7 @@ pub use winit::event_loop::EventLoopBuilder;
 /// You can configure any platform specific details required on top of the default configuration
 /// done by `EFrame`.
 #[cfg(not(target_arch = "wasm32"))]
+#[cfg(any(feature = "glow", feature = "wgpu"))]
 pub type EventLoopBuilderHook = Box<dyn FnOnce(&mut EventLoopBuilder<UserEvent>)>;
 
 /// This is how your app is created.
@@ -317,6 +320,7 @@ pub struct NativeOptions {
     pub hardware_acceleration: HardwareAcceleration,
 
     /// What rendering backend to use.
+    #[cfg(any(feature = "glow", feature = "wgpu"))]
     pub renderer: Renderer,
 
     /// Only used if the `dark-light` feature is enabled:
@@ -355,6 +359,7 @@ pub struct NativeOptions {
     /// event loop before it is run.
     ///
     /// Note: A [`NativeOptions`] clone will not include any `event_loop_builder` hook.
+    #[cfg(any(feature = "glow", feature = "wgpu"))]
     pub event_loop_builder: Option<EventLoopBuilderHook>,
 
     #[cfg(feature = "glow")]
@@ -381,9 +386,13 @@ impl Clone for NativeOptions {
     fn clone(&self) -> Self {
         Self {
             icon_data: self.icon_data.clone(),
+
+            #[cfg(any(feature = "glow", feature = "wgpu"))]
             event_loop_builder: None, // Skip any builder callbacks if cloning
+
             #[cfg(feature = "wgpu")]
             wgpu_options: self.wgpu_options.clone(),
+
             ..*self
         }
     }
@@ -397,8 +406,10 @@ impl Default for NativeOptions {
             maximized: false,
             decorated: true,
             fullscreen: false,
+
             #[cfg(target_os = "macos")]
             fullsize_content: false,
+
             drag_and_drop_support: true,
             icon_data: None,
             initial_window_pos: None,
@@ -413,14 +424,22 @@ impl Default for NativeOptions {
             depth_buffer: 0,
             stencil_buffer: 0,
             hardware_acceleration: HardwareAcceleration::Preferred,
+
+            #[cfg(any(feature = "glow", feature = "wgpu"))]
             renderer: Renderer::default(),
+
             follow_system_theme: cfg!(target_os = "macos") || cfg!(target_os = "windows"),
             default_theme: Theme::Dark,
             run_and_return: true,
+
+            #[cfg(any(feature = "glow", feature = "wgpu"))]
             event_loop_builder: None,
+
             #[cfg(feature = "glow")]
             shader_version: None,
+
             centered: false,
+
             #[cfg(feature = "wgpu")]
             wgpu_options: egui_wgpu::WgpuConfiguration::default(),
         }
@@ -559,6 +578,7 @@ pub enum WebGlContextOption {
 /// What rendering backend to use.
 ///
 /// You need to enable the "glow" and "wgpu" features to have a choice.
+#[cfg(any(feature = "glow", feature = "wgpu"))]
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 #[cfg_attr(feature = "serde", serde(rename_all = "snake_case"))]
@@ -572,6 +592,7 @@ pub enum Renderer {
     Wgpu,
 }
 
+#[cfg(any(feature = "glow", feature = "wgpu"))]
 impl Default for Renderer {
     fn default() -> Self {
         #[cfg(feature = "glow")]
@@ -587,6 +608,7 @@ impl Default for Renderer {
     }
 }
 
+#[cfg(any(feature = "glow", feature = "wgpu"))]
 impl std::fmt::Display for Renderer {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
@@ -599,6 +621,7 @@ impl std::fmt::Display for Renderer {
     }
 }
 
+#[cfg(any(feature = "glow", feature = "wgpu"))]
 impl std::str::FromStr for Renderer {
     type Err = String;
 
@@ -811,6 +834,7 @@ impl Frame {
     }
 
     /// for integrations only: call once per frame
+    #[cfg(any(feature = "glow", feature = "wgpu"))]
     pub(crate) fn take_app_output(&mut self) -> backend::AppOutput {
         std::mem::take(&mut self.output)
     }
diff --git a/crates/eframe/src/lib.rs b/crates/eframe/src/lib.rs
index de031d2a..a2181c58 100644
--- a/crates/eframe/src/lib.rs
+++ b/crates/eframe/src/lib.rs
@@ -137,6 +137,7 @@ pub async fn start_web(
 // When compiling natively
 
 #[cfg(not(target_arch = "wasm32"))]
+#[cfg(any(feature = "glow", feature = "wgpu"))]
 mod native;
 
 /// This is how you start a native (desktop) app.
@@ -179,6 +180,7 @@ mod native;
 /// This function can fail if we fail to set up a graphics context.
 #[cfg(not(target_arch = "wasm32"))]
 #[allow(clippy::needless_pass_by_value)]
+#[cfg(any(feature = "glow", feature = "wgpu"))]
 pub fn run_native(
     app_name: &str,
     native_options: NativeOptions,
@@ -233,24 +235,28 @@ pub type Result<T> = std::result::Result<T, Error>;
 
 // ---------------------------------------------------------------------------
 
-/// Profiling macro for feature "puffin"
 #[cfg(not(target_arch = "wasm32"))]
-macro_rules! profile_function {
+#[cfg(any(feature = "glow", feature = "wgpu"))]
+mod profiling_scopes {
+    /// Profiling macro for feature "puffin"
+    macro_rules! profile_function {
     ($($arg: tt)*) => {
         #[cfg(feature = "puffin")]
         puffin::profile_function!($($arg)*);
     };
 }
-#[cfg(not(target_arch = "wasm32"))]
-pub(crate) use profile_function;
+    pub(crate) use profile_function;
 
-/// Profiling macro for feature "puffin"
-#[cfg(not(target_arch = "wasm32"))]
-macro_rules! profile_scope {
+    /// Profiling macro for feature "puffin"
+    macro_rules! profile_scope {
     ($($arg: tt)*) => {
         #[cfg(feature = "puffin")]
         puffin::profile_scope!($($arg)*);
     };
 }
+    pub(crate) use profile_scope;
+}
+
 #[cfg(not(target_arch = "wasm32"))]
-pub(crate) use profile_scope;
+#[cfg(any(feature = "glow", feature = "wgpu"))]
+pub(crate) use profiling_scopes::*;