From 1ecc6bb473df7b38f1a6717811bf38ee629a2ce7 Mon Sep 17 00:00:00 2001
From: Grant Elbert <grant.elbert@smartthings.com>
Date: Sat, 19 Jun 2021 23:34:38 -0500
Subject: [PATCH] parser: force proc macro fallback

Incorate https://github.com/alexcrichton/proc-macro2/pull/220 to fix the
case where a binary which is built with `panic = "abort"` aborts when
calling into cbdingen functionality.

https://github.com/eqrion/cbindgen/issues/569

Signed-off-by: Grant Elbert <grant.elbert@smartthings.com>
---
 src/bindgen/parser.rs                    |  2 ++
 tests/basic_cbindgen_wrapper/.gitignore  |  1 +
 tests/basic_cbindgen_wrapper/Cargo.toml  | 13 ++++++++++
 tests/basic_cbindgen_wrapper/src/main.rs | 23 ++++++++++++++++++
 tests/panic_abort_strategy.rs            | 31 ++++++++++++++++++++++++
 5 files changed, 70 insertions(+)
 create mode 100644 tests/basic_cbindgen_wrapper/.gitignore
 create mode 100644 tests/basic_cbindgen_wrapper/Cargo.toml
 create mode 100644 tests/basic_cbindgen_wrapper/src/main.rs
 create mode 100644 tests/panic_abort_strategy.rs

diff --git a/src/bindgen/parser.rs b/src/bindgen/parser.rs
index 2f4d980d4..103542d9a 100644
--- a/src/bindgen/parser.rs
+++ b/src/bindgen/parser.rs
@@ -206,6 +206,7 @@ impl<'a> Parser<'a> {
                         self.config.parse.expand.profile,
                     )
                     .map_err(|x| Error::CargoExpand(pkg.name.clone(), x))?;
+                proc_macro2::fallback::force();
                 let i = syn::parse_file(&s).map_err(|x| Error::ParseSyntaxError {
                     crate_name: pkg.name.clone(),
                     src_path: "".to_owned(),
@@ -243,6 +244,7 @@ impl<'a> Parser<'a> {
                         src_path: mod_path.to_str().unwrap().to_owned(),
                     })?;
 
+                proc_macro2::fallback::force();
                 let i = syn::parse_file(&s).map_err(|x| Error::ParseSyntaxError {
                     crate_name: pkg.name.clone(),
                     src_path: mod_path.to_string_lossy().into(),
diff --git a/tests/basic_cbindgen_wrapper/.gitignore b/tests/basic_cbindgen_wrapper/.gitignore
new file mode 100644
index 000000000..03314f77b
--- /dev/null
+++ b/tests/basic_cbindgen_wrapper/.gitignore
@@ -0,0 +1 @@
+Cargo.lock
diff --git a/tests/basic_cbindgen_wrapper/Cargo.toml b/tests/basic_cbindgen_wrapper/Cargo.toml
new file mode 100644
index 000000000..0487e2bd1
--- /dev/null
+++ b/tests/basic_cbindgen_wrapper/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+name = "panic_abort"
+version = "0.1.0"
+edition = "2018"
+
+[profile.dev]
+panic = "abort"
+
+[profile.release]
+panic = "abort"
+
+[dependencies]
+cbindgen = { path = "../.." }
diff --git a/tests/basic_cbindgen_wrapper/src/main.rs b/tests/basic_cbindgen_wrapper/src/main.rs
new file mode 100644
index 000000000..73e86e179
--- /dev/null
+++ b/tests/basic_cbindgen_wrapper/src/main.rs
@@ -0,0 +1,23 @@
+use std::{env, process};
+
+fn exit_with_usage(exe_name: impl AsRef<str>) -> ! {
+    eprintln!("Usage: {} MANIFEST_PATH PKG_NAME", exe_name.as_ref());
+    process::exit(1);
+}
+
+/// A cbindgen wrapper whose return status can be leveraged by tests. Of note is that it is built
+/// with `panic = "abort"` with respect to https://github.com/alexcrichton/proc-macro2/pull/220.
+pub fn main() {
+    let opts = env::args().collect::<Vec<String>>();
+    if opts.len() < 3 {
+        exit_with_usage(&opts[0]);
+    }
+    let crate_dir = &opts[1];
+    let pkg_name = &opts[2];
+
+    cbindgen::Builder::new()
+        .with_crate(crate_dir)
+        .with_parse_expand(&vec![pkg_name])
+        .generate()
+        .expect("Unable to generate bindings");
+}
diff --git a/tests/panic_abort_strategy.rs b/tests/panic_abort_strategy.rs
new file mode 100644
index 000000000..4faa824a3
--- /dev/null
+++ b/tests/panic_abort_strategy.rs
@@ -0,0 +1,31 @@
+use std::{env, path::PathBuf, process::Command};
+
+#[test]
+fn test_panic_abort_strategy() {
+    // Validates cbindgen's incorporation of https://github.com/alexcrichton/proc-macro2/issues/218.
+    //
+    // Run a binary whose profile specifies `panic = "abort"` and where the binary proceeds to
+    // call into cbindgen's generation functionality. Prior to the incorporation of the above this
+    // would result in the binary aborting.
+    let cargo = env::var("CARGO").unwrap_or_else(|_| String::from("cargo"));
+    let mut cmd = Command::new(cargo);
+
+    let tests_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap()).join("tests");
+    let wrapper_manifest_path = tests_dir.join("basic_cbindgen_wrapper").join("Cargo.toml");
+    let arg_manifest_dir = tests_dir.join("rust").join("expand_dep");
+
+    cmd.arg("run");
+    cmd.arg("--manifest-path");
+    cmd.arg(wrapper_manifest_path.as_path().to_str().unwrap());
+    cmd.arg("--");
+    cmd.arg(arg_manifest_dir.as_path().to_str().unwrap());
+    cmd.arg("expand-dep");
+
+    let output = cmd.output().expect("Failed to run cargo command");
+
+    assert!(
+        output.status.success(),
+        "Cargo run failed: {}",
+        String::from_utf8_lossy(&output.stderr)
+    );
+}