refactor: make Config always compiled

simplifies usage while still making parsing optional for less generated code

Author: abonander

Cargo.toml

@@ -54,16 +54,14 @@ features = ["all-databases", "_unstable-all-types", "_unstable-doc"]
 rustdoc-args = ["--cfg", "docsrs"]
 
 [features]
-default = ["any", "macros", "migrate", "json", "config-all"]
+default = ["any", "macros", "migrate", "json", "sqlx-toml"]
 
 derive = ["sqlx-macros/derive"]
 macros = ["derive", "sqlx-macros/macros"]
 migrate = ["sqlx-core/migrate", "sqlx-macros?/migrate", "sqlx-mysql?/migrate", "sqlx-postgres?/migrate", "sqlx-sqlite?/migrate"]
 
-# Enable parsing of `sqlx.toml` for configuring macros, migrations, or both.
-config-macros = ["sqlx-macros?/config-macros"]
-config-migrate = ["sqlx-macros?/config-migrate"]
-config-all = ["config-macros", "config-migrate"]
+# Enable parsing of `sqlx.toml` for configuring macros and migrations.
+sqlx-toml = ["sqlx-core/sqlx-toml", "sqlx-macros?/sqlx-toml"]
 
 # intended mainly for CI and docs
 all-databases = ["mysql", "sqlite", "postgres", "any"]
@@ -79,7 +77,7 @@ _unstable-all-types = [
     "bit-vec",
 ]
 # Render documentation that wouldn't otherwise be shown (e.g. `sqlx_core::config`).
-_unstable-doc = ["config-all", "sqlx-core/_unstable-doc"]
+_unstable-doc = []
 
 # Base runtime features without TLS
 runtime-async-std = ["_rt-async-std", "sqlx-core/_rt-async-std", "sqlx-macros?/_rt-async-std"]

sqlx-cli/Cargo.toml

@@ -51,7 +51,8 @@ filetime = "0.2"
 backoff = { version = "0.4.0", features = ["futures", "tokio"] }
 
 [features]
-default = ["postgres", "sqlite", "mysql", "native-tls", "completions"]
+default = ["postgres", "sqlite", "mysql", "native-tls", "completions", "sqlx-toml"]
+
 rustls = ["sqlx/runtime-tokio-rustls"]
 native-tls = ["sqlx/runtime-tokio-native-tls"]
 
@@ -65,6 +66,8 @@ openssl-vendored = ["openssl/vendored"]
 
 completions = ["dep:clap_complete"]
 
+sqlx-toml = ["sqlx/sqlx-toml"]
+
 [dev-dependencies]
 assert_cmd = "2.0.11"
 tempfile = "3.10.1"

sqlx-core/Cargo.toml

@@ -12,7 +12,7 @@ features = ["offline"]
 
 [features]
 default = []
-migrate = ["sha2", "crc", "config-migrate"]
+migrate = ["sha2", "crc"]
 
 any = []
 
@@ -30,11 +30,13 @@ _tls-none = []
 # support offline/decoupled building (enables serialization of `Describe`)
 offline = ["serde", "either/serde"]
 
-config = ["serde", "toml/parse"]
-config-macros = ["config"]
-config-migrate = ["config"]
+# Enable parsing of `sqlx.toml`.
+# For simplicity, the `config` module is always enabled,
+# but disabling this disables the `serde` derives and the `toml` crate,
+# which is a good bit less code to compile if the feature isn't being used.
+sqlx-toml = ["serde", "toml/parse"]
 
-_unstable-doc = ["config-macros", "config-migrate"]
+_unstable-doc = ["sqlx-toml"]
 
 [dependencies]
 # Runtimes

sqlx-core/src/config/common.rs

@@ -1,5 +1,6 @@
 /// Configuration shared by multiple components.
-#[derive(Debug, Default, serde::Deserialize)]
+#[derive(Debug, Default)]
+#[cfg_attr(feature = "sqlx-toml", derive(serde::Deserialize))]
 pub struct Config {
     /// Override the database URL environment variable.
     ///
@@ -36,3 +37,9 @@ pub struct Config {
     /// and the ones used in `bar` will use `BAR_DATABASE_URL`.
     pub database_url_var: Option<String>,
 }
+
+impl Config {
+    pub fn database_url_var(&self) -> &str {
+        self.database_url_var.as_deref().unwrap_or("DATABASE_URL")    
+    }
+}

sqlx-core/src/config/macros.rs

@@ -1,8 +1,8 @@
 use std::collections::BTreeMap;
 
 /// Configuration for the `query!()` family of macros.
-#[derive(Debug, Default, serde::Deserialize)]
-#[serde(default)]
+#[derive(Debug, Default)]
+#[cfg_attr(feature = "sqlx-toml", derive(serde::Deserialize), serde(default))]
 pub struct Config {
     /// Specify the crate to use for mapping date/time types to Rust.
     ///
@@ -235,8 +235,12 @@ pub struct Config {
 }
 
 /// The crate to use for mapping date/time types to Rust.
-#[derive(Debug, Default, PartialEq, Eq, serde::Deserialize)]
-#[serde(rename_all = "snake_case")]
+#[derive(Debug, Default, PartialEq, Eq)]
+#[cfg_attr(
+    feature = "sqlx-toml",
+    derive(serde::Deserialize),
+    serde(rename_all = "snake_case")
+)]
 pub enum DateTimeCrate {
     /// Use whichever crate is enabled (`time` then `chrono`).
     #[default]

sqlx-core/src/config/migrate.rs

@@ -12,8 +12,8 @@ use std::collections::BTreeSet;
 /// if the proper precautions are not taken.
 ///
 /// Be sure you know what you are doing and that you read all relevant documentation _thoroughly_.
-#[derive(Debug, Default, serde::Deserialize)]
-#[serde(default)]
+#[derive(Debug, Default)]
+#[cfg_attr(feature = "sqlx-toml", derive(serde::Deserialize), serde(default))]
 pub struct Config {
     /// Override the name of the table used to track executed migrations.
     ///
@@ -118,8 +118,12 @@ pub struct Config {
 }
 
 /// The default type of migration that `sqlx migrate create` should create by default.
-#[derive(Debug, Default, PartialEq, Eq, serde::Deserialize)]
-#[serde(rename_all = "snake_case")]
+#[derive(Debug, Default, PartialEq, Eq)]
+#[cfg_attr(
+    feature = "sqlx-toml",
+    derive(serde::Deserialize),
+    serde(rename_all = "snake_case")
+)]
 pub enum DefaultMigrationType {
     /// Create the same migration type as that of the latest existing migration,
     /// or `Simple` otherwise.
@@ -134,8 +138,12 @@ pub enum DefaultMigrationType {
 }
 
 /// The default scheme that `sqlx migrate create` should use for version integers.
-#[derive(Debug, Default, PartialEq, Eq, serde::Deserialize)]
-#[serde(rename_all = "snake_case")]
+#[derive(Debug, Default, PartialEq, Eq)]
+#[cfg_attr(
+    feature = "sqlx-toml",
+    derive(serde::Deserialize),
+    serde(rename_all = "snake_case")
+)]
 pub enum DefaultVersioning {
     /// Infer the versioning scheme from existing migrations:
     ///

sqlx-core/src/config/mod.rs

@@ -7,6 +7,7 @@
 //!
 //! See the [reference][`_reference`] for the full `sqlx.toml` file.
 
+use std::error::Error;
 use std::fmt::Debug;
 use std::io;
 use std::path::{Path, PathBuf};
@@ -23,13 +24,11 @@ pub mod common;
 /// Configuration for the `query!()` family of macros.
 ///
 /// See [`macros::Config`] for details.
-#[cfg(feature = "config-macros")]
 pub mod macros;
 
 /// Configuration for migrations when executed using `sqlx::migrate!()` or through `sqlx-cli`.
 ///
 /// See [`migrate::Config`] for details.
-#[cfg(feature = "config-migrate")]
 pub mod migrate;
 
 /// Reference for `sqlx.toml` files
@@ -41,11 +40,12 @@ pub mod migrate;
 /// ```
 pub mod _reference {}
 
-#[cfg(test)]
+#[cfg(all(test, feature = "sqlx-toml"))]
 mod tests;
 
 /// The parsed structure of a `sqlx.toml` file.
-#[derive(Debug, Default, serde::Deserialize)]
+#[derive(Debug, Default)]
+#[cfg_attr(feature = "sqlx-toml", derive(serde::Deserialize))]
 pub struct Config {
     /// Configuration shared by multiple components.
     ///
@@ -55,21 +55,11 @@ pub struct Config {
     /// Configuration for the `query!()` family of macros.
     ///
     /// See [`macros::Config`] for details.
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(any(feature = "config-all", feature = "config-macros")))
-    )]
-    #[cfg(feature = "config-macros")]
     pub macros: macros::Config,
 
     /// Configuration for migrations when executed using `sqlx::migrate!()` or through `sqlx-cli`.
     ///
     /// See [`migrate::Config`] for details.
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(any(feature = "config-all", feature = "config-migrate")))
-    )]
-    #[cfg(feature = "config-migrate")]
     pub migrate: migrate::Config,
 }
 
@@ -90,13 +80,17 @@ pub enum ConfigError {
         std::env::VarError,
     ),
 
+    /// No configuration file was found. Not necessarily fatal.
+    #[error("config file {path:?} not found")]
+    NotFound {
+        path: PathBuf,
+    },
+
     /// An I/O error occurred while attempting to read the config file at `path`.
     ///
-    /// This includes [`io::ErrorKind::NotFound`].
-    ///
-    /// [`Self::not_found_path()`] will return the path if the file was not found.
+    /// If the error is [`io::ErrorKind::NotFound`], [`Self::NotFound`] is returned instead.
     #[error("error reading config file {path:?}")]
-    Read {
+    Io {
         path: PathBuf,
         #[source]
         error: io::Error,
@@ -105,22 +99,41 @@ pub enum ConfigError {
     /// An error in the TOML was encountered while parsing the config file at `path`.
     ///
     /// The error gives line numbers and context when printed with `Display`/`ToString`.
+    /// 
+    /// Only returned if the `sqlx-toml` feature is enabled.
     #[error("error parsing config file {path:?}")]
     Parse {
         path: PathBuf,
+        /// Type-erased [`toml::de::Error`].
         #[source]
-        error: toml::de::Error,
+        error: Box<dyn Error + Send + Sync + 'static>,
+    },
+
+    /// A `sqlx.toml` file was found or specified, but the `sqlx-toml` feature is not enabled.
+    #[error("SQLx found config file at {path:?} but the `sqlx-toml` feature was not enabled")]
+    ParseDisabled {
+        path: PathBuf
     },
 }
 
 impl ConfigError {
+    /// Create a [`ConfigError`] from a [`std::io::Error`].
+    /// 
+    /// Maps to either `NotFound` or `Io`.
+    pub fn from_io(path: PathBuf, error: io::Error) -> Self {
+        if error.kind() == io::ErrorKind::NotFound {
+            Self::NotFound { path }
+        } else {
+            Self::Io { path, error }
+        }
+    }
+    
     /// If this error means the file was not found, return the path that was attempted.
     pub fn not_found_path(&self) -> Option<&Path> {
-        match self {
-            ConfigError::Read { path, error } if error.kind() == io::ErrorKind::NotFound => {
-                Some(path)
-            }
-            _ => None,
+        if let Self::NotFound { path } = self {
+            Some(path)
+        } else {
+            None
         }
     }
 }
@@ -140,14 +153,22 @@ impl Config {
     /// If the file exists but an unrecoverable error was encountered while parsing it.
     pub fn from_crate() -> &'static Self {
         Self::try_from_crate().unwrap_or_else(|e| {
-            if let Some(path) = e.not_found_path() {
-                // Non-fatal
-                tracing::debug!("Not reading config, file {path:?} not found (error: {e})");
-                CACHE.get_or_init(Config::default)
-            } else {
+            match e {
+                ConfigError::NotFound { path } => {
+                    // Non-fatal
+                    tracing::debug!("Not reading config, file {path:?} not found");
+                    CACHE.get_or_init(Config::default)
+                }
+                // FATAL ERRORS BELOW:
                 // In the case of migrations,
                 // we can't proceed with defaults as they may be completely wrong.
-                panic!("failed to read sqlx config: {e}")
+                e @ ConfigError::ParseDisabled { .. } => {
+                    // Only returned if the file exists but the feature is not enabled.
+                    panic!("{e}")
+                }
+                e => {
+                    panic!("failed to read sqlx config: {e}")
+                }
             }
         })
     }
@@ -188,19 +209,29 @@ impl Config {
         })
     }
 
+    #[cfg(feature = "sqlx-toml")]
     fn read_from(path: PathBuf) -> Result<Self, ConfigError> {
         // The `toml` crate doesn't provide an incremental reader.
         let toml_s = match std::fs::read_to_string(&path) {
             Ok(toml) => toml,
             Err(error) => {
-                return Err(ConfigError::Read { path, error });
+                return Err(ConfigError::from_io(path, error));
             }
         };
 
         // TODO: parse and lint TOML structure before deserializing
         // Motivation: https://github.com/toml-rs/toml/issues/761
         tracing::debug!("read config TOML from {path:?}:\n{toml_s}");
 
-        toml::from_str(&toml_s).map_err(|error| ConfigError::Parse { path, error })
+        toml::from_str(&toml_s).map_err(|error| ConfigError::Parse { path, error: Box::new(error) })
+    }
+    
+    #[cfg(not(feature = "sqlx-toml"))]
+    fn read_from(path: PathBuf) -> Result<Self, ConfigError> {
+        match path.try_exists() {
+            Ok(true) => Err(ConfigError::ParseDisabled { path }),
+            Ok(false) => Err(ConfigError::NotFound { path }),
+            Err(e) => Err(ConfigError::from_io(path, e))
+        }
     }
 }

sqlx-core/src/config/tests.rs

@@ -20,7 +20,6 @@ fn assert_common_config(config: &config::common::Config) {
     assert_eq!(config.database_url_var.as_deref(), Some("FOO_DATABASE_URL"));
 }
 
-#[cfg(feature = "config-macros")]
 fn assert_macros_config(config: &config::macros::Config) {
     use config::macros::*;
 
@@ -74,7 +73,6 @@ fn assert_macros_config(config: &config::macros::Config) {
     );
 }
 
-#[cfg(feature = "config-migrate")]
 fn assert_migrate_config(config: &config::migrate::Config) {
     use config::migrate::*;
 

sqlx-core/src/lib.rs

@@ -91,7 +91,6 @@ pub mod any;
 #[cfg(feature = "migrate")]
 pub mod testing;
 
-#[cfg(feature = "config")]
 pub mod config;
 
 pub use error::{Error, Result};

sqlx-macros-core/Cargo.toml

@@ -23,9 +23,7 @@ derive = []
 macros = []
 migrate = ["sqlx-core/migrate"]
 
-config = ["sqlx-core/config"]
-config-macros = ["config", "sqlx-core/config-macros"]
-config-migrate = ["config", "sqlx-core/config-migrate"]
+sqlx-toml = ["sqlx-core/sqlx-toml"]
 
 # database
 mysql = ["sqlx-mysql"]