Prettyplease default, rustfmt opt-in via config

.github/workflows/ci.yml

@@ -19,8 +19,6 @@ jobs:
           components: rustfmt
       - run: cargo run -- expand --manifest-path tests/Cargo.toml > expand.rs
       - run: diff tests/lib.expand.rs expand.rs
-      - run: cargo run --features prettyplease -- expand --manifest-path tests/Cargo.toml > expand.rs
-      - run: diff tests/lib.expand.rs expand.rs
 
   build:
     name: Rust ${{matrix.rust}}
@@ -28,17 +26,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        rust: [nightly, beta, stable, 1.58.0]
+        rust: [nightly, beta, stable, 1.60.0]
     steps:
       - uses: actions/checkout@v3
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{matrix.rust}}
       - run: cargo check
-      - run: cargo check --features prettyplease
       - run: cargo update
       - run: cargo check
-      - run: cargo check --features prettyplease
       - run: cargo test
 
   clippy:

Cargo.toml

@@ -12,12 +12,16 @@ license = "MIT OR Apache-2.0"
 readme = "README.md"
 repository = "https://github.com/dtolnay/cargo-expand"
 
+[features]
+default = ["prettyplease"]
+prettyplease = []
+
 [dependencies]
 atty = "0.2"
 bat = { version = "0.21", default-features = false, features = ["paging", "regex-fancy"] }
 cargo-subcommand-metadata = "0.1"
 clap = { version = "3.2.5", default-features = false, features = ["deprecated", "derive", "std", "suggestions"] }
-prettyplease = { version = "0.1.13", optional = true, features = ["verbatim"] }
+prettyplease = { version = "0.1.13", features = ["verbatim"] }
 proc-macro2 = "1.0"
 quote = { version = "1.0", default-features = false }
 serde = { version = "1.0", features = ["derive"] }

build.rs

@@ -4,12 +4,10 @@ use std::path::PathBuf;
 
 fn main() {
     let mut version = env!("CARGO_PKG_VERSION").to_owned();
-    if cfg!(feature = "prettyplease") {
-        if let Ok(prettyplease_version) = env::var("DEP_PRETTYPLEASE01_VERSION") {
-            // TODO: Make this appear only if `--version --verbose` is used.
-            version.push_str(" + prettyplease ");
-            version.push_str(&prettyplease_version);
-        }
+    if let Ok(prettyplease_version) = env::var("DEP_PRETTYPLEASE01_VERSION") {
+        // TODO: Make this appear only if `--version --verbose` is used.
+        version.push_str(" + prettyplease ");
+        version.push_str(&prettyplease_version);
     }
 
     let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());

src/config.rs

@@ -16,6 +16,11 @@ pub struct Config {
     pub color: Option<String>,
     #[serde(default)]
     pub pager: bool,
+    /// Format using rustfmt instead of prettyplease. This is significantly
+    /// slower, and less reliable on macro-generated code, but produces more
+    /// aesthetic formatting when it works.
+    #[serde(default)]
+    pub rustfmt: bool,
 }
 
 pub fn deserialize() -> Config {

src/main.rs

@@ -33,13 +33,11 @@ use std::env;
 use std::ffi::OsString;
 use std::fs;
 use std::io::{self, BufRead, Write};
-#[cfg(feature = "prettyplease")]
 use std::panic::{self, PanicInfo, UnwindSafe};
 use std::path::{Path, PathBuf};
 use std::process::{self, Command, Stdio};
 use std::ptr;
 use std::str::FromStr;
-#[cfg(feature = "prettyplease")]
 use std::thread::Result as ThreadResult;
 use termcolor::{Color::Green, ColorChoice, ColorSpec, StandardStream, WriteColor};
 
@@ -139,7 +137,6 @@ fn cargo_expand() -> Result<i32> {
         return Ok(0);
     }
 
-    let mut rustfmt = None;
     if let Some(item) = &args.item {
         if args.ugly {
             let _ = writeln!(
@@ -149,20 +146,18 @@ fn cargo_expand() -> Result<i32> {
             );
             return Ok(1);
         }
-        if !cfg!(feature = "prettyplease") {
-            rustfmt = which_rustfmt();
-            if rustfmt.is_none() {
-                let _ = writeln!(
-                    io::stderr(),
-                    "ERROR: cannot expand single item ({}) without rustfmt.",
-                    item,
-                );
-                let _ = writeln!(
-                    io::stderr(),
-                    "Install rustfmt by running `rustup component add rustfmt --toolchain nightly`.",
-                );
-                return Ok(1);
-            }
+    }
+
+    let mut rustfmt = None;
+    if config.rustfmt {
+        rustfmt = which_rustfmt();
+        if rustfmt.is_none() {
+            let _ = io::stderr().write_all(
+                b"ERROR: cargo-expand configuration sets rustfmt=true, but \
+                rustfmt is not found. Install rustfmt by running `rustup \
+                component add rustfmt --toolchain nightly`.\n",
+            );
+            return Ok(1);
         }
     }
 
@@ -221,13 +216,7 @@ fn cargo_expand() -> Result<i32> {
                     return Ok(1);
                 }
             }
-            #[cfg(feature = "prettyplease")]
-            // This is behind a feature because it's probably not mature enough
-            // to use in panic=abort mode yet. I'll remove the feature and do
-            // this by default when prettyplease is further along, or when
-            // cfg(panic = "unwind") is stabilized, whichever comes first.
-            // Tracking issue: https://github.com/rust-lang/rust/issues/77443
-            {
+            if !config.rustfmt {
                 if let Ok(formatted) = ignore_panic(|| prettyplease::unparse(&syntax_tree)) {
                     stage = Stage::Formatted(formatted);
                 }
@@ -506,7 +495,6 @@ fn ignore_cargo_err(line: &str) -> bool {
     false
 }
 
-#[cfg(feature = "prettyplease")]
 fn ignore_panic<F, T>(f: F) -> ThreadResult<T>
 where
     F: UnwindSafe + FnOnce() -> T,