feat: make BuildError newtype (#326)

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### Description

This is a preparation for supporting warnings and error tracing. We need add some fields on `BuildError`.

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### Test Plan

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---

crates/rolldown_error/src/error.rs

@@ -0,0 +1,55 @@
+use std::{
+  borrow::Cow,
+  path::{Path, PathBuf},
+};
+
+use miette::Diagnostic;
+use thiserror::Error;
+
+use crate::error_kind::{
+  external_entry::ExternalEntry, unresolved_entry::UnresolvedEntry,
+  unresolved_import::UnresolvedImport, ErrorKind,
+};
+
+type StaticStr = Cow<'static, str>;
+
+#[derive(Error, Debug, Diagnostic)]
+#[error(transparent)]
+#[diagnostic(transparent)]
+pub struct BuildError(ErrorKind);
+
+impl BuildError {
+  pub fn new_with_kind(kind: ErrorKind) -> Self {
+    Self(kind)
+  }
+
+  // --- Aligned with rollup
+  pub fn entry_cannot_be_external(unresolved_id: impl AsRef<Path>) -> Self {
+    Self::new_with_kind(ErrorKind::ExternalEntry(
+      ExternalEntry { id: unresolved_id.as_ref().to_path_buf() }.into(),
+    ))
+  }
+
+  pub fn unresolved_entry(unresolved_id: impl AsRef<Path>) -> Self {
+    Self::new_with_kind(ErrorKind::UnresolvedEntry(
+      UnresolvedEntry { unresolved_id: unresolved_id.as_ref().to_path_buf() }.into(),
+    ))
+  }
+
+  pub fn unresolved_import(specifier: impl Into<StaticStr>, importer: impl Into<PathBuf>) -> Self {
+    Self::new_with_kind(ErrorKind::UnresolvedImport(
+      UnresolvedImport { specifier: specifier.into(), importer: importer.into() }.into(),
+    ))
+  }
+
+  // --- rolldown specific
+  pub fn napi_error(status: String, reason: String) -> Self {
+    Self::new_with_kind(ErrorKind::Napi { status, reason })
+  }
+}
+
+impl From<std::io::Error> for BuildError {
+  fn from(e: std::io::Error) -> Self {
+    Self::new_with_kind(ErrorKind::Io(Box::new(e)))
+  }
+}

crates/rolldown_error/src/error_kind/mod.rs

@@ -0,0 +1,40 @@
+use std::borrow::Cow;
+
+pub mod external_entry;
+// pub mod impl_to_diagnostic;
+pub mod unresolved_entry;
+pub mod unresolved_import;
+
+use miette::Diagnostic;
+use thiserror::Error;
+
+use self::{
+  external_entry::ExternalEntry, unresolved_entry::UnresolvedEntry,
+  unresolved_import::UnresolvedImport,
+};
+
+type StaticStr = Cow<'static, str>;
+
+#[derive(Error, Debug, Diagnostic)]
+pub enum ErrorKind {
+  #[diagnostic(transparent)]
+  #[error(transparent)]
+  UnresolvedEntry(Box<UnresolvedEntry>),
+
+  #[diagnostic(transparent)]
+  #[error(transparent)]
+  ExternalEntry(Box<ExternalEntry>),
+
+  #[diagnostic(transparent)]
+  #[error(transparent)]
+  UnresolvedImport(Box<UnresolvedImport>),
+
+  #[diagnostic(code = "IO_ERROR")]
+  #[error(transparent)]
+  Io(Box<std::io::Error>),
+
+  // TODO: probably should remove this error
+  #[diagnostic(code = "NAPI_ERROR")]
+  #[error("Napi error: {status}: {reason}")]
+  Napi { status: String, reason: String },
+}

crates/rolldown_error/src/lib.rs

@@ -1,5 +1,5 @@
 mod error;
-// mod error_code;
+mod error_kind;
 mod utils;
 
 use std::path::Path;