From 6344ff77e500f4d5d79ca6b0789c627cd052d236 Mon Sep 17 00:00:00 2001
From: Jan-Erik Rediger <jrediger@mozilla.com>
Date: Mon, 31 Jul 2023 20:38:47 +0200
Subject: [PATCH] uniffi_macros: Force-include the `Cargo.toml` to read

---
 uniffi_macros/src/lib.rs  | 22 ++++++++++++++++++++++
 uniffi_macros/src/util.rs | 16 ++++++++++------
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/uniffi_macros/src/lib.rs b/uniffi_macros/src/lib.rs
index ee4f600939..fcbb848713 100644
--- a/uniffi_macros/src/lib.rs
+++ b/uniffi_macros/src/lib.rs
@@ -186,9 +186,31 @@ pub fn include_scaffolding(component_name: TokenStream) -> TokenStream {
             },
             None,
         );
+
+        let toml_path = match util::manifest_path() {
+            Ok(path) => path.display().to_string(),
+            Err(_) => {
+                return quote! {
+                    compile_error!("This macro assumes the crate has a build.rs script, but $OUT_DIR is not present");
+                }.into();
+            }
+        };
+
         quote! {
             #metadata
 
+            // FIXME(HACK):
+            // Include the `Cargo.toml` file into the build.
+            // That way cargo tracks the file and other tools relying on file
+            // tracking see it as well.
+            // See https://bugzilla.mozilla.org/show_bug.cgi?id=1846223
+            // In the future we should handle that by using the `track_path::path` API,
+            // see https://github.com/rust-lang/rust/pull/84029
+            #[allow(dead_code)]
+            mod __unused {
+                const _: &[u8] = include_bytes!(#toml_path);
+            }
+
             include!(concat!(env!("OUT_DIR"), "/", #name, ".uniffi.rs"));
         }
     }.into()
diff --git a/uniffi_macros/src/util.rs b/uniffi_macros/src/util.rs
index b516666dac..2e4164b392 100644
--- a/uniffi_macros/src/util.rs
+++ b/uniffi_macros/src/util.rs
@@ -4,18 +4,24 @@
 
 use proc_macro2::{Ident, Span, TokenStream};
 use quote::{format_ident, quote, ToTokens};
+use std::path::{Path as StdPath, PathBuf};
 use syn::{
     ext::IdentExt,
     parse::{Parse, ParseStream},
     Attribute, Path, Token,
 };
 
+pub fn manifest_path() -> Result<PathBuf, String> {
+    let manifest_dir =
+        std::env::var_os("CARGO_MANIFEST_DIR").ok_or("`CARGO_MANIFEST_DIR` is not set")?;
+
+    Ok(StdPath::new(&manifest_dir).join("Cargo.toml"))
+}
+
 #[cfg(not(feature = "nightly"))]
 pub fn mod_path() -> syn::Result<String> {
     // Without the nightly feature and TokenStream::expand_expr, just return the crate name
 
-    use std::path::Path;
-
     use fs_err as fs;
     use once_cell::sync::Lazy;
     use serde::Deserialize;
@@ -38,11 +44,9 @@ pub fn mod_path() -> syn::Result<String> {
     }
 
     static LIB_CRATE_MOD_PATH: Lazy<Result<String, String>> = Lazy::new(|| {
-        let manifest_dir =
-            std::env::var_os("CARGO_MANIFEST_DIR").ok_or("`CARGO_MANIFEST_DIR` is not set")?;
+        let file = manifest_path()?;
+        let cargo_toml_bytes = fs::read(file).map_err(|e| e.to_string())?;
 
-        let cargo_toml_bytes =
-            fs::read(Path::new(&manifest_dir).join("Cargo.toml")).map_err(|e| e.to_string())?;
         let cargo_toml = toml::from_slice::<CargoToml>(&cargo_toml_bytes)
             .map_err(|e| format!("Failed to parse `Cargo.toml`: {e}"))?;