fix: remove macro dependencies (#45)

- Remove proc_macro_hack
- Remove dotenv_codegen_impl

CHANGELOG.md

@@ -10,6 +10,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 ## Changed
 
 - Minimum Supported Rust Version is now 1.56.1
+- Removed internal `dotenv_codegen_impl` crate and `proc_macro_hack` dependency
 
 ## [0.15.6] - 2022-10-17
 

Cargo.toml

@@ -1,3 +1,3 @@
 [workspace]
 
-members = ["dotenv", "dotenv_codegen", "dotenv_codegen_impl"]
+members = ["dotenv", "dotenv_codegen"]

README.md

@@ -16,8 +16,7 @@ This library loads environment variables from a _.env_ file. This is convenient
 
 1. [`dotenvy`](https://crates.io/crates/dotenvy) crate - A well-maintained fork of the `dotenv` crate.
 2. [`dotenvy_macro`](https://crates.io/crates/dotenvy_codegen) crate - A macro for compile time dotenv inspection. This is a fork of `dotenv_codegen`.
-3. [`dotenvy_codgen_impl`](https://crates.io/crates/dotenvy_codegen_impl) crate - Internal implementation for dotenvy_codegen.
-4. `dotenvy` CLI tool for running a command using the environment from a _.env_ file (currently Unix only)
+3. `dotenvy` CLI tool for running a command using the environment from a _.env_ file (currently Unix only)
 
 ## Usage
 

dotenv/README.md

@@ -16,8 +16,7 @@ This library loads environment variables from a _.env_ file. This is convenient
 
 1. [`dotenvy`](https://crates.io/crates/dotenvy) crate - A well-maintained fork of the `dotenv` crate.
 2. [`dotenvy_macro`](https://crates.io/crates/dotenvy_codegen) crate - A macro for compile time dotenv inspection. This is a fork of `dotenv_codegen`.
-3. [`dotenvy_codgen_impl`](https://crates.io/crates/dotenvy_codegen_impl) crate - Internal implementation for dotenvy_codegen.
-4. `dotenvy` CLI tool for running a command using the environment from a _.env_ file (currently Unix only)
+3. `dotenvy` CLI tool for running a command using the environment from a _.env_ file (currently Unix only)
 
 ## Usage
 

dotenv_codegen/Cargo.toml

@@ -1,5 +1,7 @@
-[package]
+[lib]
+proc-macro = true
 
+[package]
 name = "dotenvy_macro"
 version = "0.15.1"
 authors = [
@@ -20,5 +22,7 @@ edition = "2018"
 rust-version = "1.56.1"
 
 [dependencies]
-dotenvy_codegen_impl = { version = "0.15", path = "../dotenv_codegen_impl" }
-proc-macro-hack = "0.5"
+proc-macro2 = "1"
+quote = "1"
+syn = "1"
+dotenvy = { version = "0.15", path = "../dotenv" }

dotenv_codegen/README.md

@@ -6,5 +6,3 @@
 A macro for compile time dotenv inspection.
 
 This is a well-maintained fork of `dotenv_codegen`.
-
-Warning: there is an outstanding issue with rust-analyzer ([rust-analyzer #9606](https://github.com/rust-analyzer/rust-analyzer/issues/9606)) related to the `dotenv!` macro

dotenv_codegen/src/lib.rs

@@ -1,6 +1,69 @@
 #![forbid(unsafe_code)]
 
-use proc_macro_hack::proc_macro_hack;
+use std::env::{self, VarError};
 
-#[proc_macro_hack]
-pub use dotenvy_codegen_impl::dotenv;
+use quote::quote;
+use syn::parse::Parser;
+use syn::punctuated::Punctuated;
+use syn::spanned::Spanned;
+use syn::Token;
+
+#[proc_macro]
+pub fn dotenv(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    dotenv_inner(input.into()).into()
+}
+
+fn dotenv_inner(input: proc_macro2::TokenStream) -> proc_macro2::TokenStream {
+    if let Err(err) = dotenvy::dotenv() {
+        let msg = format!("Error loading .env file: {}", err);
+        return quote! {
+            compile_error!(#msg);
+        };
+    }
+
+    match expand_env(input) {
+        Ok(stream) => stream,
+        Err(e) => e.to_compile_error(),
+    }
+}
+
+fn expand_env(input_raw: proc_macro2::TokenStream) -> syn::Result<proc_macro2::TokenStream> {
+    let args = <Punctuated<syn::LitStr, Token![,]>>::parse_terminated
+        .parse(input_raw.into())
+        .expect("expected macro to be called with a comma-separated list of string literals");
+
+    let mut iter = args.iter();
+
+    let var_name = iter
+        .next()
+        .ok_or_else(|| syn::Error::new(args.span(), "dotenv! takes 1 or 2 arguments"))?
+        .value();
+    let err_msg = iter.next();
+
+    if iter.next().is_some() {
+        return Err(syn::Error::new(
+            args.span(),
+            "dotenv! takes 1 or 2 arguments",
+        ));
+    }
+
+    match env::var(&var_name) {
+        Ok(val) => Ok(quote!(#val)),
+        Err(e) => Err(syn::Error::new(
+            var_name.span(),
+            err_msg.map_or_else(
+                || match e {
+                    VarError::NotPresent => {
+                        format!("environment variable `{}` not defined", var_name)
+                    }
+
+                    VarError::NotUnicode(s) => format!(
+                        "environment variable `{}` was not valid unicode: {:?}",
+                        var_name, s
+                    ),
+                },
+                |lit| lit.value(),
+            ),
+        )),
+    }
+}