From 064dc5463e84e09d9bbab8864df25f33080adbd0 Mon Sep 17 00:00:00 2001
From: Taiki Endo <te316e89@gmail.com>
Date: Sun, 8 Sep 2024 17:41:41 +0900
Subject: [PATCH] codegen: Favor assert/panic over error

---
 tools/codegen/Cargo.toml  |  1 -
 tools/codegen/src/file.rs | 41 +++++++++++++++++++++------------------
 tools/codegen/src/main.rs | 21 +++++++++-----------
 3 files changed, 31 insertions(+), 32 deletions(-)

diff --git a/tools/codegen/Cargo.toml b/tools/codegen/Cargo.toml
index c1982ef..a281ab5 100644
--- a/tools/codegen/Cargo.toml
+++ b/tools/codegen/Cargo.toml
@@ -3,7 +3,6 @@ name = "futures-async-stream-internal-codegen"
 edition = "2021"
 
 [dependencies]
-anyhow = "1"
 fs-err = "2"
 globset = { version = "0.4", default-features = false }
 prettyplease = "0.2"
diff --git a/tools/codegen/src/file.rs b/tools/codegen/src/file.rs
index dbad092..2dc25d7 100644
--- a/tools/codegen/src/file.rs
+++ b/tools/codegen/src/file.rs
@@ -1,13 +1,13 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use std::{
+    io,
     path::{Path, PathBuf},
     process::Command,
     str,
     sync::LazyLock,
 };
 
-use anyhow::{bail, format_err, Context as _, Result};
 use fs_err as fs;
 use proc_macro2::TokenStream;
 
@@ -53,17 +53,18 @@ pub(crate) fn write(
     function_name: &str,
     path: impl AsRef<Path>,
     contents: TokenStream,
-) -> Result<()> {
-    write_raw(function_name, path.as_ref(), format_tokens(contents)?)
+) -> io::Result<()> {
+    write_raw(function_name, path.as_ref(), format_tokens(contents))
 }
 
-fn format_tokens(contents: TokenStream) -> Result<Vec<u8>> {
+#[track_caller]
+fn format_tokens(contents: TokenStream) -> Vec<u8> {
     let mut out = prettyplease::unparse(
-        &syn::parse2(contents.clone()).map_err(|e| format_err!("{e} in:\n---\n{contents}\n---"))?,
+        &syn::parse2(contents.clone()).unwrap_or_else(|e| panic!("{e} in:\n---\n{contents}\n---")),
     )
     .into_bytes();
     format_macros(&mut out);
-    Ok(out)
+    out
 }
 
 // Roughly format the code inside macro calls.
@@ -129,7 +130,7 @@ pub(crate) fn write_raw(
     function_name: &str,
     path: &Path,
     contents: impl AsRef<[u8]>,
-) -> Result<()> {
+) -> io::Result<()> {
     static LINGUIST_GENERATED: LazyLock<Vec<globset::GlobMatcher>> = LazyLock::new(|| {
         let gitattributes = fs::read_to_string(workspace_root().join(".gitattributes")).unwrap();
         let mut linguist_generated = vec![];
@@ -157,19 +158,21 @@ pub(crate) fn write_raw(
     Ok(())
 }
 
-pub(crate) fn git_ls_files(dir: &Path, filters: &[&str]) -> Result<Vec<(String, PathBuf)>> {
+#[track_caller]
+pub(crate) fn git_ls_files(dir: &Path, filters: &[&str]) -> Vec<(String, PathBuf)> {
     let mut cmd = Command::new("git");
     cmd.arg("ls-files").args(filters).current_dir(dir);
-    let output = cmd.output().with_context(|| format!("could not execute process `{cmd:?}`"))?;
-    if !output.status.success() {
-        bail!(
-            "process didn't exit successfully: `{cmd:?}`:\n\nSTDOUT:\n{0}\n{1}\n{0}\n\nSTDERR:\n{0}\n{2}\n{0}\n",
-            "-".repeat(60),
-            String::from_utf8_lossy(&output.stdout),
-            String::from_utf8_lossy(&output.stderr),
-        );
-    }
-    Ok(str::from_utf8(&output.stdout)?
+    let output =
+        cmd.output().unwrap_or_else(|e| panic!("could not execute process `{cmd:?}`: {e}"));
+    assert!(
+        output.status.success(),
+        "process didn't exit successfully: `{cmd:?}`:\n\nSTDOUT:\n{0}\n{1}\n{0}\n\nSTDERR:\n{0}\n{2}\n{0}\n",
+        "-".repeat(60),
+        String::from_utf8_lossy(&output.stdout),
+        String::from_utf8_lossy(&output.stderr),
+    );
+    str::from_utf8(&output.stdout)
+        .unwrap()
         .lines()
         .map(str::trim)
         .filter_map(|f| {
@@ -182,5 +185,5 @@ pub(crate) fn git_ls_files(dir: &Path, filters: &[&str]) -> Result<Vec<(String,
             }
             Some((f.to_owned(), p))
         })
-        .collect())
+        .collect()
 }
diff --git a/tools/codegen/src/main.rs b/tools/codegen/src/main.rs
index cc350b3..3b92043 100644
--- a/tools/codegen/src/main.rs
+++ b/tools/codegen/src/main.rs
@@ -10,30 +10,29 @@ use std::{
     path::Path,
 };
 
-use anyhow::Result;
 use fs_err as fs;
 use quote::{format_ident, quote, ToTokens};
 use syn::visit_mut::{self, VisitMut};
 
 use crate::file::*;
 
-fn main() -> Result<()> {
-    gen_assert_impl()?;
-    Ok(())
+fn main() {
+    gen_assert_impl();
 }
 
-fn gen_assert_impl() -> Result<()> {
+fn gen_assert_impl() {
     const NOT_SEND: &[&str] = &[];
     const NOT_SYNC: &[&str] = &[];
     const NOT_UNPIN: &[&str] = &[];
+    // TODO: we can revert 477aa991a925fa5d6c5c11815cb4c6e16574a025 as fixed in https://github.com/rust-lang/rust/pull/125392
     // const NOT_UNWIND_SAFE: &[&str] = &["future::ResumeTy"];
     // const NOT_REF_UNWIND_SAFE: &[&str] = &["future::ResumeTy"];
 
     let workspace_root = &workspace_root();
     let out_dir = &workspace_root.join("src/gen");
-    fs::create_dir_all(out_dir)?;
+    fs::create_dir_all(out_dir).unwrap();
 
-    let files: BTreeSet<String> = git_ls_files(&workspace_root.join("src"), &["*.rs"])?
+    let files: BTreeSet<String> = git_ls_files(&workspace_root.join("src"), &["*.rs"])
         .into_iter()
         .filter_map(|(file_name, path)| {
             // Assertions are only needed for the library's public APIs.
@@ -48,8 +47,8 @@ fn gen_assert_impl() -> Result<()> {
     let mut visited_types = HashSet::new();
     let mut use_generics_helpers = false;
     for f in &files {
-        let s = fs::read_to_string(f)?;
-        let mut ast = syn::parse_file(&s)?;
+        let s = fs::read_to_string(f).unwrap();
+        let mut ast = syn::parse_file(&s).unwrap();
 
         let module = if f.ends_with("lib.rs") {
             vec![]
@@ -293,9 +292,7 @@ fn gen_assert_impl() -> Result<()> {
             #tokens
         };
     });
-    write(function_name!(), out_dir.join("assert_impl.rs"), out)?;
-
-    Ok(())
+    write(function_name!(), out_dir.join("assert_impl.rs"), out).unwrap();
 }
 
 #[must_use]