Use the source-relative path in include_str!

Pest needs the full path with CARGO_MANIFEST_DIR to read the grammar
file, but when emitting `include_str!` the original path (relative to
the Rust source file) should be used.

generator/src/generator.rs

@@ -7,8 +7,6 @@
 // option. All files in the project carrying such notice may not be copied,
 // modified, or distributed except according to those terms.
 
-use std::path::PathBuf;
-
 use proc_macro2::{Span, TokenStream};
 use quote::{ToTokens, TokenStreamExt};
 use syn::{self, Generics, Ident};
@@ -21,7 +19,7 @@ use pest_meta::UNICODE_PROPERTY_NAMES;
 pub fn generate(
     name: Ident,
     generics: &Generics,
-    path: Option<PathBuf>,
+    path: Option<String>,
     rules: Vec<OptimizedRule>,
     defaults: Vec<&str>,
     include_grammar: bool,
@@ -31,7 +29,7 @@ pub fn generate(
     let builtins = generate_builtin_rules();
     let include_fix = if include_grammar {
         match path {
-            Some(ref path) => generate_include(&name, path.to_str().expect("non-Unicode path")),
+            Some(ref path) => generate_include(&name, path),
             None => quote!(),
         }
     } else {
@@ -167,14 +165,9 @@ fn generate_builtin_rules() -> Vec<(&'static str, TokenStream)> {
 // Needed because Cargo doesn't watch for changes in grammars.
 fn generate_include(name: &Ident, path: &str) -> TokenStream {
     let const_name = Ident::new(&format!("_PEST_GRAMMAR_{}", name), Span::call_site());
-    // Need to make this relative to the current directory since the path to the file
-    // is derived from the CARGO_MANIFEST_DIR environment variable
-    let mut current_dir = std::env::current_dir().expect("Unable to get current directory");
-    current_dir.push(path);
-    let relative_path = current_dir.to_str().expect("path contains invalid unicode");
     quote! {
         #[allow(non_upper_case_globals)]
-        const #const_name: &'static str = include_str!(#relative_path);
+        const #const_name: &'static str = include_str!(#path);
     }
 }
 
@@ -936,14 +929,11 @@ mod tests {
             expr: OptimizedExpr::Str("b".to_owned()),
         }];
         let defaults = vec!["ANY"];
-        let mut current_dir = std::env::current_dir().expect("Unable to get current directory");
-        current_dir.push("test.pest");
-        let test_path = current_dir.to_str().expect("path contains invalid unicode");
         assert_eq!(
-            generate(name, &generics, Some(PathBuf::from("test.pest")), rules, defaults, true).to_string(),
+            generate(name, &generics, Some(String::from("test.pest")), rules, defaults, true).to_string(),
             quote! {
                 #[allow(non_upper_case_globals)]
-                const _PEST_GRAMMAR_MyParser: &'static str = include_str!(#test_path);
+                const _PEST_GRAMMAR_MyParser: &'static str = include_str!("test.pest");
 
                 #[allow(dead_code, non_camel_case_types, clippy::upper_case_acronyms)]
                 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]

generator/src/lib.rs

@@ -39,19 +39,19 @@ pub fn derive_parser(input: TokenStream, include_grammar: bool) -> TokenStream {
     let (name, generics, content) = parse_derive(ast);
 
     let (data, path) = match content {
-        GrammarSource::File(ref path) => {
+        GrammarSource::File(path) => {
             let root = env::var("CARGO_MANIFEST_DIR").unwrap_or_else(|_| ".".into());
-            let path = Path::new(&root).join("src/").join(&path);
-            let file_name = match path.file_name() {
+            let full_path = Path::new(&root).join("src/").join(&path);
+            let file_name = match full_path.file_name() {
                 Some(file_name) => file_name,
                 None => panic!("grammar attribute should point to a file"),
             };
 
-            let data = match read_file(&path) {
+            let data = match read_file(&full_path) {
                 Ok(data) => data,
                 Err(error) => panic!("error opening {:?}: {}", file_name, error),
             };
-            (data, Some(path.clone()))
+            (data, Some(path))
         }
         GrammarSource::Inline(content) => (content, None),
     };