Try switching to thiserror for the library part (Variant #2)

.github/workflows/ci.yml

@@ -4,7 +4,6 @@ on:
   push:
     branches: [ "main" ]
   pull_request:
-    branches: [ "main" ]
 
 env:
   CARGO_TERM_COLOR: always

Cargo.toml

@@ -12,7 +12,15 @@ categories = ["command-line-utilities"]
 exclude = ["/tools/"]
 
 [features]
-bin = ["dep:clap", "dep:clap_complete", "dep:ctrlc", "dep:shadow-rs", "dep:sysinfo", "dep:winresource"]
+bin = [
+    "dep:anyhow",
+    "dep:clap",
+    "dep:clap_complete",
+    "dep:ctrlc",
+    "dep:shadow-rs",
+    "dep:sysinfo",
+    "dep:winresource"
+]
 capi = []
 
 [profile.release]
@@ -24,14 +32,15 @@ name = "keepawake"
 required-features = ["bin"]
 
 [dependencies]
-anyhow = "1.0.65"
+anyhow = { version = "1.0.65", optional = true }
 cfg-if = "1.0.0"
 clap = { version = "4.0.2", features = ["derive"], optional = true }
 clap_complete = { version = "4.0.2", optional = true }
 ctrlc = { version = "3.2.3", features = ["termination"], optional = true }
 derive_builder = "0.12.0"
 shadow-rs = { version = "0.26.1", optional = true }
 sysinfo = { version = "0.30.5", optional = true }
+thiserror = "1.0.56"
 
 [target.'cfg(windows)'.dependencies.windows]
 version = "0.52.0"

src/lib.rs

@@ -3,7 +3,7 @@
 //! # Examples
 //!
 //! ```
-//! # fn try_main() -> anyhow::Result<()> {
+//! # fn try_main() -> keepawake::Result<()> {
 //! let _awake = keepawake::Builder::default()
 //!     .display(true)
 //!     .reason("Video playback")
@@ -16,7 +16,7 @@
 //! ```
 //!
 //! ```
-//! # fn try_main() -> anyhow::Result<()> {
+//! # fn try_main() -> keepawake::Result<()> {
 //! let _awake = keepawake::Builder::default()
 //!     .display(true)
 //!     .idle(true)
@@ -27,14 +27,30 @@
 //! # try_main();
 //! ```
 
-use anyhow::Result;
 use derive_builder::Builder;
+use thiserror::Error;
 
 mod sys;
 
 #[cfg(feature = "capi")]
 pub mod capi;
 
+/// A system error whose actual type varies by target.
+pub use sys::Error as SystemError;
+
+/// Error type.
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("builder: {0}")]
+    Builder(#[from] BuilderError),
+
+    #[error("system: {0}")]
+    System(#[from] SystemError),
+}
+
+/// A specialized [`Result`](std::result::Result) type for this crate.
+pub type Result<T, E = Error> = std::result::Result<T, E>;
+
 #[derive(Builder, Debug)]
 #[builder(public, name = "Builder", build_fn(private))]
 #[allow(dead_code)] // Some fields are unused on some platforms

src/sys/linux.rs

@@ -7,11 +7,12 @@
 //! [ScreenSaver]: https://people.freedesktop.org/~hadess/idle-inhibition-spec/re01.html
 //! [systemd Inhibitor Locks]:(https://www.freedesktop.org/wiki/Software/systemd/inhibit/
 
-use anyhow::Result;
 use zbus::{blocking::Connection, dbus_proxy};
 
 use crate::Options;
 
+pub type Error = zbus::Error;
+
 #[dbus_proxy(
     interface = "org.freedesktop.login1.Manager",
     default_service = "org.freedesktop.login1",
@@ -51,7 +52,7 @@ pub struct KeepAwake {
 }
 
 impl KeepAwake {
-    pub fn new(options: Options) -> Result<Self> {
+    pub fn new(options: Options) -> Result<Self, zbus::Error> {
         let mut awake = Self {
             options,
 

src/sys/macos.rs

@@ -4,7 +4,8 @@
 //!
 //! [`IOPMAssertionCreateWithName`]: https://developer.apple.com/documentation/iokit/1557134-iopmassertioncreatewithname
 
-use anyhow::{anyhow, Result};
+use std::error;
+
 use apple_sys::IOKit::{
     kIOPMAssertionLevelOn, kIOReturnSuccess, CFStringRef, IOPMAssertionCreateWithName,
     IOPMAssertionRelease,
@@ -13,6 +14,8 @@ use core_foundation::{base::TCFType, string::CFString};
 
 use crate::Options;
 
+pub type Error = Box<dyn error::Error + Send + Sync>;
+
 #[allow(non_upper_case_globals)]
 const kIOPMAssertionTypePreventUserIdleSystemSleep: &str = "PreventUserIdleSystemSleep";
 
@@ -31,7 +34,7 @@ pub struct KeepAwake {
 }
 
 impl KeepAwake {
-    pub fn new(options: Options) -> Result<Self> {
+    pub fn new(options: Options) -> Result<Self, Error> {
         let mut awake = Self {
             options,
             display_assertion: 0,
@@ -42,7 +45,7 @@ impl KeepAwake {
         Ok(awake)
     }
 
-    fn set(&mut self) -> Result<()> {
+    fn set(&mut self) -> Result<(), Error> {
         if self.options.display {
             unsafe {
                 let result = IOPMAssertionCreateWithName(
@@ -55,7 +58,7 @@ impl KeepAwake {
                 );
                 if result != kIOReturnSuccess as i32 {
                     // TODO Better error?
-                    return Err(anyhow!("IO error: {:#x}", result));
+                    return Err(format!("IO error: {:#x}", result).into());
                 }
             }
         }
@@ -70,7 +73,7 @@ impl KeepAwake {
                     &mut self.idle_assertion,
                 );
                 if result != kIOReturnSuccess as i32 {
-                    return Err(anyhow!("IO error: {:#x}", result));
+                    return Err(format!("IO error: {:#x}", result).into());
                 }
             }
         }
@@ -85,7 +88,7 @@ impl KeepAwake {
                     &mut self.sleep_assertion,
                 );
                 if result != kIOReturnSuccess as i32 {
-                    return Err(anyhow!("IO error: {:#x}", result));
+                    return Err(format!("IO error: {:#x}", result).into());
                 }
             }
         }

src/sys/windows.rs

@@ -7,7 +7,6 @@
 //! [`SetThreadExecutionState`]: https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-setthreadexecutionstate
 //! [`PowerSetRequest`]: https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-powersetrequest
 
-use anyhow::Result;
 use windows::core::Error as WindowsError;
 use windows::Win32::System::Power::{
     SetThreadExecutionState, ES_AWAYMODE_REQUIRED, ES_CONTINUOUS, ES_DISPLAY_REQUIRED,
@@ -16,13 +15,15 @@ use windows::Win32::System::Power::{
 
 use crate::Options;
 
+pub type Error = WindowsError;
+
 pub struct KeepAwake {
     options: Options,
     previous: EXECUTION_STATE,
 }
 
 impl KeepAwake {
-    pub fn new(options: Options) -> Result<Self> {
+    pub fn new(options: Options) -> Result<Self, Error> {
         let mut awake = KeepAwake {
             options,
             previous: Default::default(),
@@ -31,7 +32,7 @@ impl KeepAwake {
         Ok(awake)
     }
 
-    fn set(&mut self) -> Result<(), WindowsError> {
+    fn set(&mut self) -> Result<(), Error> {
         let mut esflags = ES_CONTINUOUS;
 
         if self.options.display {