chore(config): leverage proc macros (#9111)

### Description

This PR leverages
[derive_setters](https://crates.io/crates/derive_setters) and
[merge](https://docs.rs/merge/latest/merge/index.html) to reduce the
amount of changes required when adding a field to the configuration
options.

The manual setup is error prone as there are 4 places that need to be
updated and forgetting the final place will result in code compiling,
but the field never getting layered properly.

### Testing Instructions

Existing unit & integration tests, but also looking what the proc macros
are generating (outputs shown are produced using `rust-analyzer`'s
[Expand
macro](https://rust-analyzer.github.io/manual.html#expand-macro-recursively)
feature:

Output of `#[derive(Setters)]`
```
impl TurborepoConfigBuilder {
    pub fn with_api_url(mut self, value: Option<String>) -> Self {
        self.override_config.api_url = value;
        self
    }
...
```
Which exactly matches what `create_builder` would produce:
```
pub fn with_api_url(mut self, value: Option<String>) -> Self {
    self.override_config.api_url = value;
    self
}
```

`#derive(Merge)` produces
```
impl ::merge::Merge for ConfigurationOptions {
    fn merge(&mut self, other: Self) {
        ::merge::Merge::merge(&mut self.api_url, other.api_url);
...
```
and `Merge` is defined for `Option` as :
```
impl<T> Merge for Option<T> {
    fn merge(&mut self, mut other: Self) {
        if !self.is_some() {
            *self = other.take();
        }
    }
}
```
[source](https://docs.rs/merge/latest/src/merge/lib.rs.html#139-145)

So `self.api_url` will only be set to `other.api_url` if there isn't a
value present which is the behavior we want since we merge configs from
highest to lowest precedence.

---------

Co-authored-by: Nicholas Yang <nicholas.yang@vercel.com>

Cargo.toml

@@ -96,6 +96,7 @@ console = "0.15.5"
 console-subscriber = "0.1.8"
 crossbeam-channel = "0.5.8"
 dashmap = "5.4.0"
+derive_setters = "0.1.6"
 dialoguer = "0.10.3"
 dunce = "1.0.3"
 either = "1.9.0"
@@ -108,6 +109,7 @@ indicatif = "0.17.3"
 indoc = "2.0.0"
 itertools = "0.10.5"
 lazy_static = "1.4.0"
+merge = "0.1.0"
 mime = "0.3.16"
 notify = "6.1.1"
 once_cell = "1.17.1"

crates/turborepo-lib/Cargo.toml

@@ -52,6 +52,7 @@ const_format = "0.2.30"
 convert_case = "0.6.0"
 crossterm = "0.26"
 ctrlc = { version = "3.4.0", features = ["termination"] }
+derive_setters = { workspace = true }
 dialoguer = { workspace = true, features = ["fuzzy-select"] }
 dirs-next = "2.0.0"
 dunce = { workspace = true }
@@ -70,6 +71,7 @@ itertools = { workspace = true }
 jsonc-parser = { version = "0.21.0" }
 lazy_static = { workspace = true }
 libc = "0.2.140"
+merge = { workspace = true }
 miette = { workspace = true, features = ["fancy"] }
 nix = "0.26.2"
 notify = { workspace = true }

crates/turborepo-lib/src/config/mod.rs

@@ -6,8 +6,10 @@ use std::{collections::HashMap, ffi::OsString, io};
 
 use camino::{Utf8Path, Utf8PathBuf};
 use convert_case::{Case, Casing};
+use derive_setters::Setters;
 use env::{EnvVars, OverrideEnvVars};
 use file::{AuthFile, ConfigFile};
+use merge::Merge;
 use miette::{Diagnostic, NamedSource, SourceSpan};
 use serde::Deserialize;
 use struct_iterable::Iterable;
@@ -173,15 +175,6 @@ pub enum Error {
     },
 }
 
-macro_rules! create_builder {
-    ($func_name:ident, $property_name:ident, $type:ty) => {
-        pub fn $func_name(mut self, value: $type) -> Self {
-            self.override_config.$property_name = value;
-            self
-        }
-    };
-}
-
 const DEFAULT_API_URL: &str = "https://vercel.com/api";
 const DEFAULT_LOGIN_URL: &str = "https://vercel.com";
 const DEFAULT_TIMEOUT: u64 = 30;
@@ -190,8 +183,13 @@ const DEFAULT_UPLOAD_TIMEOUT: u64 = 60;
 // We intentionally don't derive Serialize so that different parts
 // of the code that want to display the config can tune how they
 // want to display and what fields they want to include.
-#[derive(Deserialize, Default, Debug, PartialEq, Eq, Clone, Iterable)]
+#[derive(Deserialize, Default, Debug, PartialEq, Eq, Clone, Iterable, Merge, Setters)]
 #[serde(rename_all = "camelCase")]
+// Generate setters for the builder type that set these values on its override_config field
+#[setters(
+    prefix = "with_",
+    generate_delegates(ty = "TurborepoConfigBuilder", field = "override_config")
+)]
 pub struct ConfigurationOptions {
     #[serde(alias = "apiurl")]
     #[serde(alias = "ApiUrl")]
@@ -336,44 +334,6 @@ impl ConfigurationOptions {
     }
 }
 
-macro_rules! create_set_if_empty {
-    ($func_name:ident, $property_name:ident, $type:ty) => {
-        fn $func_name(&mut self, value: &mut Option<$type>) {
-            if self.$property_name.is_none() {
-                if let Some(value) = value.take() {
-                    self.$property_name = Some(value);
-                }
-            }
-        }
-    };
-}
-
-// Private setters used only for construction
-impl ConfigurationOptions {
-    create_set_if_empty!(set_api_url, api_url, String);
-    create_set_if_empty!(set_login_url, login_url, String);
-    create_set_if_empty!(set_team_slug, team_slug, String);
-    create_set_if_empty!(set_team_id, team_id, String);
-    create_set_if_empty!(set_token, token, String);
-    create_set_if_empty!(set_signature, signature, bool);
-    create_set_if_empty!(set_enabled, enabled, bool);
-    create_set_if_empty!(set_preflight, preflight, bool);
-    create_set_if_empty!(set_timeout, timeout, u64);
-    create_set_if_empty!(set_ui, ui, UIMode);
-    create_set_if_empty!(set_allow_no_package_manager, allow_no_package_manager, bool);
-    create_set_if_empty!(set_daemon, daemon, bool);
-    create_set_if_empty!(set_env_mode, env_mode, EnvMode);
-    create_set_if_empty!(set_cache_dir, cache_dir, Utf8PathBuf);
-    create_set_if_empty!(set_scm_base, scm_base, String);
-    create_set_if_empty!(set_scm_head, scm_head, String);
-    create_set_if_empty!(set_spaces_id, spaces_id, String);
-    create_set_if_empty!(
-        set_root_turbo_json_path,
-        root_turbo_json_path,
-        AbsoluteSystemPathBuf
-    );
-}
-
 // Maps Some("") to None to emulate how Go handles empty strings
 fn non_empty_str(s: Option<&str>) -> Option<&str> {
     s.filter(|s| !s.is_empty())
@@ -428,30 +388,6 @@ impl TurborepoConfigBuilder {
             .unwrap_or_else(get_lowercased_env_vars)
     }
 
-    create_builder!(with_api_url, api_url, Option<String>);
-    create_builder!(with_login_url, login_url, Option<String>);
-    create_builder!(with_team_slug, team_slug, Option<String>);
-    create_builder!(with_team_id, team_id, Option<String>);
-    create_builder!(with_token, token, Option<String>);
-    create_builder!(with_signature, signature, Option<bool>);
-    create_builder!(with_enabled, enabled, Option<bool>);
-    create_builder!(with_preflight, preflight, Option<bool>);
-    create_builder!(with_timeout, timeout, Option<u64>);
-    create_builder!(with_ui, ui, Option<UIMode>);
-    create_builder!(
-        with_allow_no_package_manager,
-        allow_no_package_manager,
-        Option<bool>
-    );
-    create_builder!(with_daemon, daemon, Option<bool>);
-    create_builder!(with_env_mode, env_mode, Option<EnvMode>);
-    create_builder!(with_cache_dir, cache_dir, Option<Utf8PathBuf>);
-    create_builder!(
-        with_root_turbo_json_path,
-        root_turbo_json_path,
-        Option<AbsoluteSystemPathBuf>
-    );
-
     pub fn build(&self) -> Result<ConfigurationOptions, Error> {
         // Priority, from least significant to most significant:
         // - shared configuration (turbo.json)
@@ -483,27 +419,8 @@ impl TurborepoConfigBuilder {
         let config = sources.into_iter().try_fold(
             ConfigurationOptions::default(),
             |mut acc, current_source| {
-                let mut current_source_config = current_source.get_configuration_options(&acc)?;
-                acc.set_api_url(&mut current_source_config.api_url);
-                acc.set_login_url(&mut current_source_config.login_url);
-                acc.set_team_slug(&mut current_source_config.team_slug);
-                acc.set_team_id(&mut current_source_config.team_id);
-                acc.set_token(&mut current_source_config.token);
-                acc.set_signature(&mut current_source_config.signature);
-                acc.set_enabled(&mut current_source_config.enabled);
-                acc.set_preflight(&mut current_source_config.preflight);
-                acc.set_timeout(&mut current_source_config.timeout);
-                acc.set_spaces_id(&mut current_source_config.spaces_id);
-                acc.set_ui(&mut current_source_config.ui);
-                acc.set_allow_no_package_manager(
-                    &mut current_source_config.allow_no_package_manager,
-                );
-                acc.set_daemon(&mut current_source_config.daemon);
-                acc.set_env_mode(&mut current_source_config.env_mode);
-                acc.set_scm_base(&mut current_source_config.scm_base);
-                acc.set_scm_head(&mut current_source_config.scm_head);
-                acc.set_cache_dir(&mut current_source_config.cache_dir);
-                acc.set_root_turbo_json_path(&mut current_source_config.root_turbo_json_path);
+                let current_source_config = current_source.get_configuration_options(&acc)?;
+                acc.merge(current_source_config);
                 Ok(acc)
             },
         );