improve n2 error display (#266)

* refactor: improve error messages for opening db failures

* update test

crates/moon/tests/test_cases/mod.rs

@@ -6202,3 +6202,29 @@ fn test_moon_doc() {
         "#]],
     );
 }
+
+#[test]
+fn test_failed_to_fill_whole_buffer() {
+    let dir = TestDir::new("hello.in");
+    check(
+        &get_stderr_on_success_with_args_and_replace_dir(&dir, ["check"]),
+        expect![[r#"
+            Finished. moon: ran 1 task, now up to date
+        "#]],
+    );
+    let moon_db_path = dir.join("./target/wasm-gc/release/check/check.moon_db");
+    if moon_db_path.exists() {
+        std::fs::remove_file(&moon_db_path).unwrap();
+    }
+    std::fs::write(&moon_db_path, "").unwrap();
+    check(
+        &get_stderr_with_args_and_replace_dir(&dir, ["check"]),
+        expect![[r#"
+            error: internal build state error: $ROOT/target/wasm-gc/release/check/check.moon_db
+
+            Caused by:
+                0: failed to open build database
+                1: failed to fill whole buffer
+        "#]],
+    );
+}

crates/moonbuild/src/fmt.rs

@@ -32,6 +32,7 @@ use n2::smallmap::SmallMap;
 use std::rc::Rc;
 
 use crate::gen::cmd_builder::CommandBuilder;
+use crate::gen::n2_errors::{N2Error, N2ErrorKind};
 
 pub fn format_package(dir: &Path) -> anyhow::Result<i32> {
     let mut errors = vec![];
@@ -213,8 +214,10 @@ pub fn gen_n2_fmt_state(
 
     let mut hashes = n2graph::Hashes::default();
     let n2_db_path = &moonbuild_opt.target_dir.join("format.db");
-    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes)
-        .with_context(|| format!("failed to process n2 db: {}", n2_db_path.display()))?;
+    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes).map_err(|e| N2Error {
+        path: n2_db_path.to_path_buf(),
+        source: N2ErrorKind::OpenDataBaseError(e),
+    })?;
 
     Ok(State {
         graph,
@@ -310,8 +313,10 @@ pub fn gen_n2_fmt_check_state(
 
     let mut hashes = n2graph::Hashes::default();
     let n2_db_path = &moonbuild_opt.target_dir.join("format.db");
-    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes)
-        .with_context(|| format!("failed to process n2 db: {}", n2_db_path.display()))?;
+    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes).map_err(|e| N2Error {
+        path: n2_db_path.to_path_buf(),
+        source: N2ErrorKind::OpenDataBaseError(e),
+    })?;
 
     Ok(State {
         graph,

crates/moonbuild/src/gen/gen_build.rs

@@ -16,12 +16,13 @@
 //
 // For inquiries, you can contact us via e-mail at [email protected].
 
-use anyhow::{bail, Context, Ok};
+use anyhow::{bail, Ok};
 use moonutil::common::TargetBackend::*;
 use moonutil::module::ModuleDB;
 use moonutil::package::{JsFormat, Package};
 
 use super::cmd_builder::CommandBuilder;
+use super::n2_errors::{N2Error, N2ErrorKind};
 use crate::gen::MiAlias;
 use std::path::{Path, PathBuf};
 use std::rc::Rc;
@@ -444,8 +445,10 @@ pub fn gen_n2_build_state(
 
     let mut hashes = n2graph::Hashes::default();
     let n2_db_path = &target_dir.join("build.moon_db");
-    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes)
-        .with_context(|| format!("failed to process n2 db: {}", n2_db_path.display()))?;
+    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes).map_err(|e| N2Error {
+        path: n2_db_path.to_path_buf(),
+        source: N2ErrorKind::OpenDataBaseError(e),
+    })?;
 
     Ok(State {
         graph,

crates/moonbuild/src/gen/gen_bundle.rs

@@ -16,7 +16,7 @@
 //
 // For inquiries, you can contact us via e-mail at [email protected].
 
-use anyhow::{bail, Context};
+use anyhow::bail;
 use indexmap::IndexMap;
 use moonutil::module::ModuleDB;
 use moonutil::package::Package;
@@ -29,6 +29,7 @@ use std::rc::Rc;
 use moonutil::common::{MoonbuildOpt, MooncOpt, MOON_PKG_JSON};
 
 use super::cmd_builder::CommandBuilder;
+use super::n2_errors::{N2Error, N2ErrorKind};
 use crate::gen::MiAlias;
 
 #[derive(Debug)]
@@ -307,8 +308,10 @@ pub fn gen_n2_bundle_state(
 
     let mut hashes = n2graph::Hashes::default();
     let n2_db_path = &target_dir.join("build.moon_db");
-    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes)
-        .with_context(|| format!("failed to process n2 db: {}", n2_db_path.display()))?;
+    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes).map_err(|e| N2Error {
+        path: n2_db_path.to_path_buf(),
+        source: N2ErrorKind::OpenDataBaseError(e),
+    })?;
 
     Ok(State {
         graph,

crates/moonbuild/src/gen/gen_check.rs

@@ -17,8 +17,9 @@
 // For inquiries, you can contact us via e-mail at [email protected].
 
 use super::cmd_builder::CommandBuilder;
+use super::n2_errors::{N2Error, N2ErrorKind};
 use crate::gen::MiAlias;
-use anyhow::{bail, Context};
+use anyhow::bail;
 use indexmap::map::IndexMap;
 use moonutil::module::ModuleDB;
 use moonutil::package::Package;
@@ -368,8 +369,10 @@ pub fn gen_n2_check_state(
 
     let mut hashes = n2graph::Hashes::default();
     let n2_db_path = &target_dir.join("check.moon_db");
-    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes)
-        .with_context(|| format!("failed to process n2 db: {}", n2_db_path.display()))?;
+    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes).map_err(|e| N2Error {
+        path: n2_db_path.to_path_buf(),
+        source: N2ErrorKind::OpenDataBaseError(e),
+    })?;
 
     let default = graph.get_start_nodes();
 

crates/moonbuild/src/gen/gen_runtest.rs

@@ -16,7 +16,7 @@
 //
 // For inquiries, you can contact us via e-mail at [email protected].
 
-use anyhow::{bail, Context, Ok};
+use anyhow::{bail, Ok};
 use colored::Colorize;
 use moonutil::common::{DriverKind, GeneratedTestDriver, MOONBITLANG_CORE};
 use moonutil::module::ModuleDB;
@@ -32,6 +32,7 @@ use n2::graph::{self as n2graph, Build, BuildIns, BuildOuts, FileLoc};
 use n2::load::State;
 use n2::smallmap::SmallMap;
 
+use crate::gen::n2_errors::{N2Error, N2ErrorKind};
 use crate::gen::MiAlias;
 
 #[derive(Debug)]
@@ -918,8 +919,10 @@ pub fn gen_n2_runtest_state(
 
     let mut hashes = n2graph::Hashes::default();
     let n2_db_path = &moonbuild_opt.target_dir.join("build.moon_db");
-    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes)
-        .with_context(|| format!("failed to process n2 db: {}", n2_db_path.display()))?;
+    let db = n2::db::open(n2_db_path, &mut graph, &mut hashes).map_err(|e| N2Error {
+        path: n2_db_path.to_path_buf(),
+        source: N2ErrorKind::OpenDataBaseError(e),
+    })?;
 
     Ok(State {
         graph,

crates/moonbuild/src/gen/mod.rs

@@ -21,6 +21,7 @@ pub mod gen_build;
 pub mod gen_bundle;
 pub mod gen_check;
 pub mod gen_runtest;
+pub mod n2_errors;
 pub mod util;
 
 // WORKAROUND for do not test coverage on coverage library itself

crates/moonbuild/src/gen/n2_errors.rs

@@ -0,0 +1,33 @@
+// moon: The build system and package manager for MoonBit.
+// Copyright (C) 2024 International Digital Economy Academy
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+// For inquiries, you can contact us via e-mail at [email protected].
+
+use std::path::PathBuf;
+
+#[derive(Debug, thiserror::Error)]
+#[error("internal build state error: {path}")]
+pub struct N2Error {
+    pub path: PathBuf,
+    #[source]
+    pub(crate) source: N2ErrorKind,
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum N2ErrorKind {
+    #[error("failed to open build database")]
+    OpenDataBaseError(#[from] anyhow::Error),
+}