use thiserror in third-party-licenses tool

Author: timon-schelling

Cargo.lock

@@ -13,6 +13,7 @@ desktop = ["dep:cef-dll-sys", "dep:scraper"]
 serde = { workspace = true }
 serde_json = { workspace = true }
 lzma-rust2 = { workspace = true }
+thiserror = { workspace = true }
 
 # Optional workspace dependencies
 cef-dll-sys = { workspace = true, optional = true }

tools/third-party-licenses/Cargo.toml

@@ -1,9 +1,9 @@
-use crate::{LicenceSource, LicenseEntry, Package};
+use crate::{Error, LicenceSource, LicenseEntry, Package};
 use serde::Deserialize;
 use std::fs;
 use std::hash::{Hash, Hasher};
 use std::path::PathBuf;
-use std::process::{self, Command};
+use std::process::Command;
 
 pub struct CargoLicenseSource {}
 
@@ -14,8 +14,8 @@ impl CargoLicenseSource {
 }
 
 impl LicenceSource for CargoLicenseSource {
-	fn licenses(&self) -> Vec<LicenseEntry> {
-		parse(run())
+	fn licenses(&self) -> Result<Vec<LicenseEntry>, Error> {
+		Ok(parse(run()?))
 	}
 }
 
@@ -84,23 +84,18 @@ fn parse(parsed: Output) -> Vec<LicenseEntry> {
 		.collect()
 }
 
-fn run() -> Output {
+fn run() -> Result<Output, Error> {
 	let output = Command::new("cargo")
 		.args(["about", "generate", "--format", "json", "--frozen"])
 		.current_dir(env!("CARGO_WORKSPACE_DIR"))
 		.output()
-		.unwrap_or_else(|e| {
-			eprintln!("Failed to run cargo about generate: {e}");
-			process::exit(1)
-		});
+		.map_err(|e| Error::Io(e, "Failed to run cargo about generate".into()))?;
 
 	if !output.status.success() {
-		eprintln!("cargo about generate failed:\n{}", String::from_utf8_lossy(&output.stderr));
-		process::exit(1)
+		return Err(Error::Command(format!("cargo about generate failed:\n{}", String::from_utf8_lossy(&output.stderr))));
 	}
 
-	serde_json::from_str(&String::from_utf8(output.stdout).expect("cargo about generate should return valid UTF-8")).unwrap_or_else(|e| {
-		eprintln!("Failed to parse cargo about generate JSON: {e}");
-		process::exit(1)
-	})
+	let stdout = String::from_utf8(output.stdout).map_err(|e| Error::Utf8(e, "cargo about generate returned invalid UTF-8".into()))?;
+
+	serde_json::from_str(&stdout).map_err(|e| Error::Json(e, "Failed to parse cargo about generate JSON".into()))
 }

tools/third-party-licenses/src/cargo.rs

@@ -1,11 +1,11 @@
 use lzma_rust2::XzReader;
 use scraper::{Html, Selector};
+use std::fs;
 use std::hash::Hash;
 use std::io::Read;
 use std::path::PathBuf;
-use std::{fs, process};
 
-use crate::{LicenceSource, LicenseEntry, Package};
+use crate::{Error, LicenceSource, LicenseEntry, Package};
 
 pub struct CefLicenseSource;
 
@@ -16,15 +16,15 @@ impl CefLicenseSource {
 }
 
 impl LicenceSource for CefLicenseSource {
-	fn licenses(&self) -> Vec<LicenseEntry> {
-		let html = read();
-		parse(&html)
+	fn licenses(&self) -> Result<Vec<LicenseEntry>, Error> {
+		let html = read()?;
+		Ok(parse(&html))
 	}
 }
 
 impl Hash for CefLicenseSource {
 	fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
-		read().hash(state)
+		read().unwrap().hash(state)
 	}
 }
 
@@ -64,42 +64,29 @@ fn parse(html: &str) -> Vec<LicenseEntry> {
 		.collect()
 }
 
-fn read() -> String {
+fn read() -> Result<String, Error> {
 	let cef_path = PathBuf::from(env!("CEF_PATH"));
 	let cef_credits = std::fs::read_dir(&cef_path)
-		.unwrap_or_else(|e| {
-			eprintln!("Failed to read CEF_PATH directory {}: {e}", cef_path.display());
-			process::exit(1);
-		})
+		.map_err(|e| Error::Io(e, format!("Failed to read CEF_PATH directory {}", cef_path.display())))?
 		.filter_map(|entry| entry.ok())
 		.find(|entry| {
 			let name = entry.file_name();
 			name.eq_ignore_ascii_case("credits.html") || name.eq_ignore_ascii_case("credits.html.xz")
 		})
 		.map(|entry| entry.path())
-		.unwrap_or_else(|| {
-			eprintln!("Could not find CREDITS.html or CREDITS.html.xz in {}", cef_path.display());
-			process::exit(1);
-		});
+		.ok_or_else(|| Error::CefCreditsNotFound(cef_path.clone()))?;
 
 	let decompress_xz = cef_credits.extension().map(|ext| ext.eq_ignore_ascii_case("xz")).unwrap_or(false);
 
 	if decompress_xz {
-		let file = fs::File::open(&cef_credits).unwrap_or_else(|e| {
-			eprintln!("Failed to open CEF credits file {}: {e}", cef_credits.display());
-			process::exit(1);
-		});
+		let file = fs::File::open(&cef_credits).map_err(|e| Error::Io(e, format!("Failed to open CEF credits file {}", cef_credits.display())))?;
 		let mut reader = XzReader::new(file, false);
 		let mut html = String::new();
-		reader.read_to_string(&mut html).unwrap_or_else(|e| {
-			eprintln!("Failed to decompress CEF credits file {}: {e}", cef_credits.display());
-			process::exit(1);
-		});
-		html
+		reader
+			.read_to_string(&mut html)
+			.map_err(|e| Error::Io(e, format!("Failed to decompress CEF credits file {}", cef_credits.display())))?;
+		Ok(html)
 	} else {
-		fs::read_to_string(&cef_credits).unwrap_or_else(|e| {
-			eprintln!("Failed to read CEF credits file {}: {e}", cef_credits.display());
-			process::exit(1);
-		})
+		fs::read_to_string(&cef_credits).map_err(|e| Error::Io(e, format!("Failed to read CEF credits file {}", cef_credits.display())))
 	}
 }

tools/third-party-licenses/src/cef.rs

@@ -1,7 +1,7 @@
 use std::collections::HashMap;
+use std::fs;
 use std::hash::{DefaultHasher, Hash, Hasher};
 use std::path::PathBuf;
-use std::{fs, process};
 
 mod cargo;
 #[cfg(feature = "desktop")]
@@ -13,8 +13,27 @@ use crate::cargo::CargoLicenseSource;
 use crate::cef::CefLicenseSource;
 use crate::npm::NpmLicenseSource;
 
+#[derive(Debug, thiserror::Error)]
+pub enum Error {
+	#[error("{1}: {0}")]
+	Io(#[source] std::io::Error, String),
+
+	#[error("{1}: {0}")]
+	Json(#[source] serde_json::Error, String),
+
+	#[error("{1}: {0}")]
+	Utf8(#[source] std::string::FromUtf8Error, String),
+
+	#[error("{0}")]
+	Command(String),
+
+	#[cfg(feature = "desktop")]
+	#[error("Could not find CREDITS.html or CREDITS.html.xz in {0}")]
+	CefCreditsNotFound(PathBuf),
+}
+
 pub trait LicenceSource: std::hash::Hash {
-	fn licenses(&self) -> Vec<LicenseEntry>;
+	fn licenses(&self) -> Result<Vec<LicenseEntry>, Error>;
 }
 
 pub struct LicenseEntry {
@@ -39,6 +58,13 @@ struct Run<'a> {
 }
 
 fn main() {
+	if let Err(e) = run() {
+		eprintln!("Error: {e}");
+		std::process::exit(1);
+	}
+}
+
+fn run() -> Result<(), Error> {
 	let manifest_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
 	let workspace_dir = PathBuf::from(env!("CARGO_WORKSPACE_DIR"));
 
@@ -71,32 +97,26 @@ fn main() {
 
 	if current_hash == fs::read_to_string(&current_hash_path).unwrap_or_default() {
 		eprintln!("No changes in licenses detected, skipping generation.");
-		return;
+		return Ok(());
 	}
 	eprintln!("Changes in licenses detected, generating new license file.");
 
 	let licenses = merge_filter_dedup_and_sort(vec![
-		cargo_source.licenses(),
-		npm_source.licenses(),
+		cargo_source.licenses()?,
+		npm_source.licenses()?,
 		#[cfg(feature = "desktop")]
-		cef_source.licenses(),
+		cef_source.licenses()?,
 	]);
 	let formatted = format_credits(&licenses);
 
 	#[cfg(feature = "desktop")]
-	let output = compress(&formatted);
+	let output = compress(&formatted)?;
 	#[cfg(not(feature = "desktop"))]
 	let output = formatted.as_bytes().to_vec();
 	if let Some(parent) = output_path.parent() {
-		fs::create_dir_all(parent).unwrap_or_else(|e| {
-			eprintln!("Failed to create directory {}: {e}", parent.display());
-			std::process::exit(1);
-		});
+		fs::create_dir_all(parent).map_err(|e| Error::Io(e, format!("Failed to create directory {}", parent.display())))?;
 	}
-	fs::write(&output_path, &output).unwrap_or_else(|e| {
-		eprintln!("Failed to write {}: {e}", &output_path.display());
-		std::process::exit(1);
-	});
+	fs::write(&output_path, &output).map_err(|e| Error::Io(e, format!("Failed to write {}", output_path.display())))?;
 	run.output = &output;
 
 	let hash = {
@@ -105,10 +125,9 @@ fn main() {
 		format!("{:016x}", hasher.finish())
 	};
 
-	fs::write(&current_hash_path, hash).unwrap_or_else(|e| {
-		eprintln!("Failed to write hash file {}: {e}", current_hash_path.display());
-		process::exit(1);
-	});
+	fs::write(&current_hash_path, hash).map_err(|e| Error::Io(e, format!("Failed to write hash file {}", current_hash_path.display())))?;
+
+	Ok(())
 }
 
 fn format_credits(licenses: &Vec<LicenseEntry>) -> String {
@@ -210,20 +229,11 @@ fn dedup_by_licence_text(vec: Vec<LicenseEntry>) -> Vec<LicenseEntry> {
 }
 
 #[cfg(feature = "desktop")]
-fn compress(content: &str) -> Vec<u8> {
+fn compress(content: &str) -> Result<Vec<u8>, Error> {
 	use std::io::Write;
 	let mut buf = Vec::new();
-	let mut writer = lzma_rust2::XzWriter::new(&mut buf, lzma_rust2::XzOptions::default()).unwrap_or_else(|e| {
-		eprintln!("Failed to create XZ writer: {e}");
-		std::process::exit(1);
-	});
-	writer.write_all(content.as_bytes()).unwrap_or_else(|e| {
-		eprintln!("Failed to write compressed credits: {e}");
-		std::process::exit(1);
-	});
-	writer.finish().unwrap_or_else(|e| {
-		eprintln!("Failed to finish XZ compression: {e}");
-		std::process::exit(1);
-	});
-	buf
+	let mut writer = lzma_rust2::XzWriter::new(&mut buf, lzma_rust2::XzOptions::default()).map_err(|e| Error::Io(e, "Failed to create XZ writer".into()))?;
+	writer.write_all(content.as_bytes()).map_err(|e| Error::Io(e, "Failed to write compressed credits".into()))?;
+	writer.finish().map_err(|e| Error::Io(e, "Failed to finish XZ compression".into()))?;
+	Ok(buf)
 }

tools/third-party-licenses/src/main.rs

@@ -1,10 +1,9 @@
 use std::collections::HashMap;
 use std::fs;
 use std::path::PathBuf;
-use std::process;
 use std::process::Command;
 
-use crate::{LicenceSource, LicenseEntry, Package};
+use crate::{Error, LicenceSource, LicenseEntry, Package};
 
 pub struct NpmLicenseSource {
 	dir: PathBuf,
@@ -16,8 +15,8 @@ impl NpmLicenseSource {
 }
 
 impl LicenceSource for NpmLicenseSource {
-	fn licenses(&self) -> Vec<LicenseEntry> {
-		parse(run(&self.dir))
+	fn licenses(&self) -> Result<Vec<LicenseEntry>, Error> {
+		Ok(parse(run(&self.dir)?))
 	}
 }
 
@@ -66,28 +65,21 @@ fn parse(parsed: Output) -> Vec<LicenseEntry> {
 		.collect()
 }
 
-fn run(dir: &std::path::Path) -> Output {
+fn run(dir: &std::path::Path) -> Result<Output, Error> {
 	#[cfg(not(target_os = "windows"))]
 	let mut cmd = Command::new("npx");
 	#[cfg(target_os = "windows")]
 	let mut cmd = Command::new("npx.cmd");
 	cmd.args(["license-checker-rseidelsohn", "--production", "--json"]);
 	cmd.current_dir(dir);
 
-	let output = cmd.output().unwrap_or_else(|e| {
-		eprintln!("Failed to run npx license-checker-rseidelsohn: {e}");
-		process::exit(1);
-	});
+	let output = cmd.output().map_err(|e| Error::Io(e, "Failed to run npx license-checker-rseidelsohn".into()))?;
 
 	if !output.status.success() {
-		eprintln!("npx license-checker-rseidelsohn failed:\n{}", String::from_utf8_lossy(&output.stderr));
-		process::exit(1);
+		return Err(Error::Command(format!("npx license-checker-rseidelsohn failed:\n{}", String::from_utf8_lossy(&output.stderr))));
 	}
 
-	let json_str = String::from_utf8(output.stdout).expect("Invalid UTF-8 from license-checker");
+	let json_str = String::from_utf8(output.stdout).map_err(|e| Error::Utf8(e, "Invalid UTF-8 from license-checker".into()))?;
 
-	serde_json::from_str(&json_str).unwrap_or_else(|e| {
-		eprintln!("Failed to parse license-checker JSON: {e}");
-		process::exit(1)
-	})
+	serde_json::from_str(&json_str).map_err(|e| Error::Json(e, "Failed to parse license-checker JSON".into()))
 }