proof-of-concept of type overrides using the CLI

README.md

@@ -118,6 +118,6 @@ Feel free to open an issue, discuss using GitHub discussions or open a PR.
 [See CONTRIBUTING.md](https://github.com/Aleph-Alpha/ts-rs/blob/main/CONTRIBUTING.md)
 
 ### MSRV
-The Minimum Supported Rust Version for this crate is 1.63.0
+The Minimum Supported Rust Version for this crate is 1.72.0
 
 License: MIT

cli/Cargo.toml

@@ -6,5 +6,7 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-clap = { version = "4", features = ["derive"]}
+clap = { version = "4", features = ["derive"] }
 color-eyre = "0.6"
+serde = { version = "1", features = ["derive"] }
+toml = "0.8"

cli/src/cargo.rs

@@ -2,7 +2,7 @@ use std::process::{Command, Stdio};
 
 use color_eyre::Result;
 
-use crate::{args::Args, path};
+use crate::{config::Args, path};
 
 macro_rules! feature {
     ($cargo_invocation: expr, $args: expr, { $($field: ident => $feature: literal),* $(,)? }) => {
@@ -16,7 +16,7 @@ macro_rules! feature {
     };
 }
 
-pub fn invoke(args: &Args) -> Result<()> {
+pub fn invoke(cfg: &Args) -> Result<()> {
     let mut cargo_invocation = Command::new("cargo");
 
     cargo_invocation
@@ -26,20 +26,25 @@ pub fn invoke(args: &Args) -> Result<()> {
         .arg("ts-rs/export")
         .arg("--features")
         .arg("ts-rs/generate-metadata")
-        .stdout(if args.no_capture {
+        .stdout(if cfg.no_capture {
             Stdio::inherit()
         } else {
             Stdio::piped()
         })
-        .env("TS_RS_EXPORT_DIR", path::absolute(&args.output_directory)?);
+        .env("TS_RS_EXPORT_DIR", path::absolute(cfg.output_directory())?);
 
-    feature!(cargo_invocation, args, {
+    for (rust, ts) in &cfg.overrides {
+        let env = format!("TS_RS_INTERNAL_OVERRIDE_{rust}");
+        cargo_invocation.env(env, ts);
+    }
+
+    feature!(cargo_invocation, cfg, {
         no_warnings => "no-serde-warnings",
         esm_imports => "import-esm",
         format => "format",
     });
 
-    if args.no_capture {
+    if cfg.no_capture {
         cargo_invocation.arg("--").arg("--nocapture");
     } else {
         cargo_invocation.arg("--quiet");

cli/src/config.rs

@@ -0,0 +1,153 @@
+use std::{
+    collections::HashMap,
+    path::{Path, PathBuf},
+};
+
+use clap::Parser;
+use color_eyre::{eyre::bail, owo_colors::OwoColorize, Result};
+use serde::Deserialize;
+
+#[derive(Parser, Debug)]
+#[allow(clippy::struct_excessive_bools)]
+pub struct Args {
+    #[clap(skip)]
+    pub overrides: HashMap<String, String>,
+
+    /// Path to the `ts-rs` config file
+    #[arg(long)]
+    pub config: Option<PathBuf>,
+
+    /// Defines where your TS bindings will be saved by setting `TS_RS_EXPORT_DIR`
+    #[arg(long, short)]
+    pub output_directory: Option<PathBuf>,
+
+    /// Disables warnings caused by using serde attributes that ts-rs cannot process
+    #[arg(long)]
+    pub no_warnings: bool,
+
+    /// Adds the ".js" extension to import paths
+    #[arg(long)]
+    pub esm_imports: bool,
+
+    /// Formats the generated TypeScript files
+    #[arg(long)]
+    pub format: bool,
+
+    /// Generates an index.ts file in your --output-directory that re-exports all
+    /// types generated by ts-rs
+    #[arg(long = "index")]
+    pub generate_index_ts: bool,
+
+    /// Generates only a single index.ts file in your --output-directory that
+    /// contains all exported types
+    #[arg(long = "merge")]
+    pub merge_files: bool,
+
+    /// Do not capture `cargo test`'s output, and pass --nocapture to the test binary
+    #[arg(long = "nocapture")]
+    pub no_capture: bool,
+}
+
+// keeping this separate from `Args` for now :shrug:
+#[derive(Default, Deserialize)]
+#[serde(deny_unknown_fields, default, rename_all = "kebab-case")]
+#[allow(clippy::struct_excessive_bools)]
+pub struct Config {
+    /// Type overrides for types implemented inside ts-rs.
+    pub overrides: HashMap<String, String>,
+    pub output_directory: Option<PathBuf>,
+    pub no_warnings: bool,
+    pub esm_imports: bool,
+    pub format: bool,
+
+    #[serde(rename = "index")]
+    pub generate_index_ts: bool,
+
+    #[serde(rename = "merge")]
+    pub merge_files: bool,
+
+    #[serde(rename = "nocapture")]
+    pub no_capture: bool,
+}
+
+impl Args {
+    pub fn load() -> Result<Self> {
+        let mut args = Self::parse();
+
+        let cfg = Config::load_from_file(args.config.as_deref())?;
+
+        args.merge(cfg);
+        args.verify()?;
+
+        Ok(args)
+    }
+
+    pub fn output_directory(&self) -> &Path {
+        self.output_directory
+            .as_deref()
+            .expect("Output directory must not be `None`")
+    }
+
+    fn verify(&self) -> Result<()> {
+        if self.merge_files && self.generate_index_ts {
+            bail!(
+                "{}: --index is not compatible with --merge",
+                "Error".bold().red()
+            );
+        }
+
+        if self.output_directory.is_none() {
+            bail!("{}: You must provide the output diretory, either through the config file or the --output-directory flag", "Error".bold().red())
+        }
+
+        Ok(())
+    }
+
+    fn merge(
+        &mut self,
+        Config {
+            overrides,
+            output_directory,
+            no_warnings,
+            esm_imports,
+            format,
+            generate_index_ts,
+            merge_files,
+            no_capture,
+        }: Config,
+    ) {
+        // QUESTION: This gives the CLI flag priority over the config file's value,
+        // is this the correct order?
+        self.output_directory = output_directory.or_else(|| self.output_directory.clone());
+
+        self.overrides = overrides;
+        self.no_warnings |= no_warnings;
+        self.esm_imports |= esm_imports;
+        self.format |= format;
+        self.generate_index_ts |= generate_index_ts;
+        self.merge_files |= merge_files;
+        self.no_capture |= no_capture;
+    }
+}
+
+impl Config {
+    fn load_from_file(path: Option<&Path>) -> Result<Self> {
+        if let Some(path) = path {
+            if !path.is_file() {
+                bail!("The provided path doesn't exist");
+            }
+
+            let content = std::fs::read_to_string(path)?;
+            return Ok(toml::from_str(&content)?);
+        }
+
+        // TODO: from where do we actually load the config?
+        let path = Path::new("./ts-rs.toml");
+        if !path.is_file() {
+            return Ok(Self::default());
+        }
+
+        let content = std::fs::read_to_string(path)?;
+        Ok(toml::from_str(&content)?)
+    }
+}