module.rs

use std::{convert::TryFrom, ffi::CString, mem, ptr};

use super::{ClassBuilder, FunctionBuilder};
use crate::{
    PHP_DEBUG, PHP_ZTS,
    class::RegisteredClass,
    constant::IntoConst,
    describe::DocComments,
    error::Result,
    ffi::{ZEND_MODULE_API_NO, ext_php_rs_php_build_id},
    flags::ClassFlags,
    zend::{FunctionEntry, ModuleEntry},
};
#[cfg(feature = "enum")]
use crate::{builders::enum_builder::EnumBuilder, enum_::RegisteredEnum};

/// Builds a Zend module extension to be registered with PHP. Must be called
/// from within an external function called `get_module`, returning a mutable
/// pointer to a `ModuleEntry`.
///
/// ```rust,no_run
/// use ext_php_rs::{
///     builders::ModuleBuilder,
///     zend::ModuleEntry,
///     info_table_start, info_table_end, info_table_row
/// };
///
/// #[unsafe(no_mangle)]
/// pub extern "C" fn php_module_info(_module: *mut ModuleEntry) {
///     info_table_start!();
///     info_table_row!("column 1", "column 2");
///     info_table_end!();
/// }
///
/// #[unsafe(no_mangle)]
/// pub extern "C" fn get_module() -> *mut ModuleEntry {
///     let (entry, _) = ModuleBuilder::new("ext-name", "ext-version")
///         .info_function(php_module_info)
///         .try_into()
///         .unwrap();
///     entry.into_raw()
/// }
/// ```
#[must_use]
#[derive(Debug, Default)]
pub struct ModuleBuilder<'a> {
    pub(crate) name: String,
    pub(crate) version: String,
    pub(crate) functions: Vec<FunctionBuilder<'a>>,
    pub(crate) constants: Vec<(String, Box<dyn IntoConst + Send>, DocComments)>,
    pub(crate) classes: Vec<fn() -> ClassBuilder>,
    pub(crate) interfaces: Vec<fn() -> ClassBuilder>,
    #[cfg(feature = "enum")]
    pub(crate) enums: Vec<fn() -> EnumBuilder>,
    startup_func: Option<StartupShutdownFunc>,
    shutdown_func: Option<StartupShutdownFunc>,
    request_startup_func: Option<StartupShutdownFunc>,
    request_shutdown_func: Option<StartupShutdownFunc>,
    post_deactivate_func: Option<unsafe extern "C" fn() -> i32>,
    info_func: Option<InfoFunc>,
}

impl ModuleBuilder<'_> {
    /// Creates a new module builder with a given name and version.
    ///
    /// # Arguments
    ///
    /// * `name` - The name of the extension.
    /// * `version` - The current version of the extension.
    pub fn new(name: impl Into<String>, version: impl Into<String>) -> Self {
        Self {
            name: name.into(),
            version: version.into(),
            functions: vec![],
            constants: vec![],
            classes: vec![],
            ..Default::default()
        }
    }

    /// Overrides module name.
    ///
    /// # Arguments
    ///
    /// * `name` - The name of the extension.
    pub fn name(mut self, name: impl Into<String>) -> Self {
        self.name = name.into();
        self
    }

    /// Overrides module version.
    ///
    /// # Arguments
    ///
    /// * `version` - The current version of the extension.
    pub fn version(mut self, version: impl Into<String>) -> Self {
        self.version = version.into();
        self
    }

    /// Sets the startup function for the extension.
    ///
    /// # Arguments
    ///
    /// * `func` - The function to be called on startup.
    pub fn startup_function(mut self, func: StartupShutdownFunc) -> Self {
        self.startup_func = Some(func);
        self
    }

    /// Sets the shutdown function for the extension.
    ///
    /// # Arguments
    ///
    /// * `func` - The function to be called on shutdown.
    pub fn shutdown_function(mut self, func: StartupShutdownFunc) -> Self {
        self.shutdown_func = Some(func);
        self
    }

    /// Sets the request startup function for the extension.
    ///
    /// # Arguments
    ///
    /// * `func` - The function to be called when startup is requested.
    pub fn request_startup_function(mut self, func: StartupShutdownFunc) -> Self {
        self.request_startup_func = Some(func);
        self
    }

    /// Sets the request shutdown function for the extension.
    ///
    /// # Arguments
    ///
    /// * `func` - The function to be called when shutdown is requested.
    pub fn request_shutdown_function(mut self, func: StartupShutdownFunc) -> Self {
        self.request_shutdown_func = Some(func);
        self
    }

    /// Sets the post request shutdown function for the extension.
    ///
    /// This function can be useful if you need to do any final cleanup at the
    /// very end of a request, after all other resources have been released. For
    /// example, if your extension creates any persistent resources that last
    /// beyond a single request, you could use this function to clean those up.
    /// # Arguments
    ///
    /// * `func` - The function to be called when shutdown is requested.
    pub fn post_deactivate_function(mut self, func: unsafe extern "C" fn() -> i32) -> Self {
        self.post_deactivate_func = Some(func);
        self
    }

    /// Sets the extension information function for the extension.
    ///
    /// # Arguments
    ///
    /// * `func` - The function to be called to retrieve the information about
    ///   the extension.
    pub fn info_function(mut self, func: InfoFunc) -> Self {
        self.info_func = Some(func);
        self
    }

    /// Registers a function call observer for profiling or tracing.
    ///
    /// The factory function is called once globally during MINIT to create
    /// a singleton observer instance shared across all requests and threads.
    /// The observer must be `Send + Sync` as it may be accessed concurrently
    /// in ZTS builds.
    ///
    /// # Arguments
    ///
    /// * `factory` - A function that creates an observer instance
    ///
    /// # Example
    ///
    /// ```ignore
    /// use ext_php_rs::prelude::*;
    /// use ext_php_rs::zend::{FcallObserver, FcallInfo, ExecuteData};
    /// use ext_php_rs::types::Zval;
    ///
    /// struct MyProfiler;
    ///
    /// impl FcallObserver for MyProfiler {
    ///     fn should_observe(&self, info: &FcallInfo) -> bool {
    ///         !info.is_internal
    ///     }
    ///     fn begin(&self, _: &ExecuteData) {}
    ///     fn end(&self, _: &ExecuteData, _: Option<&Zval>) {}
    /// }
    ///
    /// #[php_module]
    /// pub fn get_module(module: ModuleBuilder) -> ModuleBuilder {
    ///     module.fcall_observer(|| MyProfiler)
    /// }
    /// ```
    ///
    /// # Panics
    ///
    /// Panics if called more than once on the same module.
    #[cfg(feature = "observer")]
    pub fn fcall_observer<F, O>(self, factory: F) -> Self
    where
        F: Fn() -> O + Send + Sync + 'static,
        O: crate::zend::FcallObserver + Send + Sync,
    {
        let boxed_factory: Box<
            dyn Fn() -> Box<dyn crate::zend::FcallObserver + Send + Sync> + Send + Sync,
        > = Box::new(move || Box::new(factory()));
        crate::zend::observer::register_fcall_observer_factory(boxed_factory);
        self
    }

    /// Registers an error observer for monitoring PHP errors.
    ///
    /// The factory function is called once during MINIT to create
    /// a singleton observer instance shared across all requests.
    /// The observer must be `Send + Sync` for ZTS builds.
    ///
    /// # Arguments
    ///
    /// * `factory` - A function that creates an observer instance
    ///
    /// # Example
    ///
    /// ```ignore
    /// use ext_php_rs::prelude::*;
    ///
    /// struct MyErrorLogger;
    ///
    /// impl ErrorObserver for MyErrorLogger {
    ///     fn should_observe(&self, error_type: ErrorType) -> bool {
    ///         ErrorType::FATAL.contains(error_type)
    ///     }
    ///
    ///     fn on_error(&self, error: &ErrorInfo) {
    ///         eprintln!("[{}:{}] {}",
    ///             error.filename.unwrap_or("<unknown>"),
    ///             error.lineno,
    ///             error.message
    ///         );
    ///     }
    /// }
    ///
    /// #[php_module]
    /// pub fn get_module(module: ModuleBuilder) -> ModuleBuilder {
    ///     module.error_observer(MyErrorLogger)
    /// }
    /// ```
    ///
    /// # Panics
    ///
    /// Panics if called more than once on the same module.
    #[cfg(feature = "observer")]
    pub fn error_observer<F, O>(self, factory: F) -> Self
    where
        F: Fn() -> O + Send + Sync + 'static,
        O: crate::zend::ErrorObserver + Send + Sync,
    {
        let boxed_factory: Box<
            dyn Fn() -> Box<dyn crate::zend::ErrorObserver + Send + Sync> + Send + Sync,
        > = Box::new(move || Box::new(factory()));
        crate::zend::error_observer::register_error_observer_factory(boxed_factory);
        self
    }

    /// Registers an exception observer for monitoring thrown PHP exceptions.
    ///
    /// The factory function is called once during MINIT to create
    /// a singleton observer instance shared across all requests.
    /// The observer must be `Send + Sync` for ZTS builds.
    ///
    /// The observer is called at throw time, before any catch blocks are evaluated.
    ///
    /// # Arguments
    ///
    /// * `factory` - A function that creates an observer instance
    ///
    /// # Example
    ///
    /// ```ignore
    /// use ext_php_rs::prelude::*;
    ///
    /// struct MyExceptionLogger;
    ///
    /// impl ExceptionObserver for MyExceptionLogger {
    ///     fn on_exception(&self, exception: &ExceptionInfo) {
    ///         eprintln!("[EXCEPTION] {}: {} at {}:{}",
    ///             exception.class_name,
    ///             exception.message.as_deref().unwrap_or("<no message>"),
    ///             exception.file.as_deref().unwrap_or("<unknown>"),
    ///             exception.line
    ///         );
    ///     }
    /// }
    ///
    /// #[php_module]
    /// pub fn get_module(module: ModuleBuilder) -> ModuleBuilder {
    ///     module.exception_observer(|| MyExceptionLogger)
    /// }
    /// ```
    ///
    /// # Panics
    ///
    /// Panics if called more than once on the same module.
    #[cfg(feature = "observer")]
    pub fn exception_observer<F, O>(self, factory: F) -> Self
    where
        F: Fn() -> O + Send + Sync + 'static,
        O: crate::zend::ExceptionObserver + Send + Sync,
    {
        let boxed_factory: Box<
            dyn Fn() -> Box<dyn crate::zend::ExceptionObserver + Send + Sync> + Send + Sync,
        > = Box::new(move || Box::new(factory()));
        crate::zend::exception_observer::register_exception_observer_factory(boxed_factory);
        self
    }

    /// Registers a zend extension handler for low-level engine hooks.
    ///
    /// Enables dual registration as both a regular PHP extension and a
    /// `zend_extension`, giving access to hooks like `op_array_handler`
    /// and `statement_handler` for building profilers and APMs.
    ///
    /// The factory function is called once during MINIT to create
    /// a singleton handler instance. The handler must be `Send + Sync`
    /// for ZTS builds.
    ///
    /// # Arguments
    ///
    /// * `factory` - A function that creates a handler instance
    ///
    /// # Example
    ///
    /// ```ignore
    /// use ext_php_rs::prelude::*;
    /// use ext_php_rs::ffi::zend_op_array;
    ///
    /// struct MyProfiler;
    ///
    /// impl ZendExtensionHandler for MyProfiler {
    ///     fn op_array_handler(&self, _op_array: &mut zend_op_array) {}
    ///     fn statement_handler(&self, _execute_data: &ExecuteData) {}
    /// }
    ///
    /// #[php_module]
    /// pub fn get_module(module: ModuleBuilder) -> ModuleBuilder {
    ///     module.zend_extension_handler(|| MyProfiler)
    /// }
    /// ```
    ///
    /// # Panics
    ///
    /// Panics if called more than once on the same module.
    #[cfg(feature = "observer")]
    pub fn zend_extension_handler<F, H>(self, factory: F) -> Self
    where
        F: Fn() -> H + Send + Sync + 'static,
        H: crate::zend::ZendExtensionHandler,
    {
        let boxed_factory: Box<
            dyn Fn() -> Box<dyn crate::zend::ZendExtensionHandler> + Send + Sync,
        > = Box::new(move || Box::new(factory()));
        crate::zend::zend_extension::register_zend_extension_factory(boxed_factory);
        self
    }

    /// Adds a function to the extension.
    ///
    /// # Arguments
    ///
    /// * `func` - The function to be added to the extension.
    pub fn function(mut self, func: FunctionBuilder<'static>) -> Self {
        self.functions.push(func);
        self
    }

    /// Adds a constant to the extension.
    ///
    /// # Arguments
    ///
    /// * `const` - Tuple containing the name, value and doc comments for the
    ///   constant. This is a tuple to support the [`wrap_constant`] macro.
    ///
    /// [`wrap_constant`]: crate::wrap_constant
    pub fn constant(
        mut self,
        r#const: (&str, impl IntoConst + Send + 'static, DocComments),
    ) -> Self {
        let (name, val, docs) = r#const;
        self.constants.push((
            name.into(),
            Box::new(val) as Box<dyn IntoConst + Send>,
            docs,
        ));
        self
    }

    /// Adds a interface to the extension.
    ///
    /// # Panics
    ///
    /// * Panics if a constant could not be registered.
    pub fn interface<T: RegisteredClass>(mut self) -> Self {
        self.interfaces.push(|| {
            let mut builder = ClassBuilder::new(T::CLASS_NAME);
            for (method, flags) in T::method_builders() {
                builder = builder.method(method, flags);
            }
            for interface in T::IMPLEMENTS {
                builder = builder.implements(*interface);
            }
            for (name, value, docs) in T::constants() {
                builder = builder
                    .dyn_constant(*name, *value, docs)
                    .expect("Failed to register constant");
            }

            if let Some(modifier) = T::BUILDER_MODIFIER {
                builder = modifier(builder);
            }

            builder = builder.flags(ClassFlags::Interface);
            // Note: interfaces should NOT have object_override because they cannot be instantiated
            builder
                .registration(|ce| {
                    T::get_metadata().set_ce(ce);
                })
                .docs(T::DOC_COMMENTS)
        });
        self
    }

    /// Adds a class to the extension.
    ///
    /// # Panics
    ///
    /// * Panics if a constant could not be registered.
    pub fn class<T: RegisteredClass>(mut self) -> Self {
        self.classes.push(|| {
            let mut builder = ClassBuilder::new(T::CLASS_NAME);
            for (method, flags) in T::method_builders() {
                builder = builder.method(method, flags);
            }
            // Methods from #[php_impl_interface] trait implementations.
            // Uses the inventory crate for cross-crate method discovery.
            for (method, flags) in T::interface_method_implementations() {
                builder = builder.method(method, flags);
            }
            if let Some(parent) = T::EXTENDS {
                builder = builder.extends(parent);
            }
            // Interfaces declared via #[php(implements(...))] attribute
            for interface in T::IMPLEMENTS {
                builder = builder.implements(*interface);
            }
            // Interfaces from #[php_impl_interface] trait implementations.
            // Uses the inventory crate for cross-crate interface discovery.
            for interface in T::interface_implementations() {
                builder = builder.implements(interface);
            }
            for (name, value, docs) in T::constants() {
                builder = builder
                    .dyn_constant(*name, *value, docs)
                    .expect("Failed to register constant");
            }
            for (name, prop_info) in T::get_properties() {
                builder = builder.property(name, prop_info.flags, None, prop_info.docs);
            }
            for (name, flags, default, docs) in T::static_properties() {
                let default_fn = default.map(|v| {
                    Box::new(move || v.as_zval(true))
                        as Box<dyn FnOnce() -> crate::error::Result<crate::types::Zval>>
                });
                builder = builder.property(*name, *flags, default_fn, docs);
            }
            if let Some(modifier) = T::BUILDER_MODIFIER {
                builder = modifier(builder);
            }

            builder
                .flags(T::FLAGS)
                .object_override::<T>()
                .registration(|ce| {
                    T::get_metadata().set_ce(ce);
                })
                .docs(T::DOC_COMMENTS)
        });
        self
    }

    /// Adds an enum to the extension.
    #[cfg(feature = "enum")]
    pub fn enumeration<T>(mut self) -> Self
    where
        T: RegisteredClass + RegisteredEnum,
    {
        self.enums.push(|| {
            let mut builder = EnumBuilder::new(T::CLASS_NAME);
            for case in T::CASES {
                builder = builder.case(case);
            }
            for (method, flags) in T::method_builders() {
                builder = builder.method(method, flags);
            }

            builder
                .registration(|ce| {
                    T::get_metadata().set_ce(ce);
                })
                .docs(T::DOC_COMMENTS)
        });

        self
    }
}

/// Artifacts from the [`ModuleBuilder`] that should be revisited inside the
/// extension startup function.
pub struct ModuleStartup {
    #[cfg(feature = "observer")]
    name: String,
    #[cfg(feature = "observer")]
    version: String,
    constants: Vec<(String, Box<dyn IntoConst + Send>)>,
    classes: Vec<fn() -> ClassBuilder>,
    interfaces: Vec<fn() -> ClassBuilder>,
    #[cfg(feature = "enum")]
    enums: Vec<fn() -> EnumBuilder>,
}

impl ModuleStartup {
    /// Completes startup of the module. Should only be called inside the module
    /// startup function.
    ///
    /// # Errors
    ///
    /// * Returns an error if a constant could not be registered.
    ///
    /// # Panics
    ///
    /// * Panics if a class could not be registered.
    pub fn startup(self, _ty: i32, mod_num: i32) -> Result<()> {
        for (name, val) in self.constants {
            val.register_constant(&name, mod_num)?;
        }

        // Interfaces must be registered before classes so that classes can implement
        // them
        self.interfaces.into_iter().map(|c| c()).for_each(|c| {
            c.register().expect("Failed to build interface");
        });

        self.classes.into_iter().map(|c| c()).for_each(|c| {
            c.register().expect("Failed to build class");
        });

        #[cfg(feature = "enum")]
        self.enums
            .into_iter()
            .map(|builder| builder())
            .for_each(|e| {
                e.register().expect("Failed to build enum");
            });

        // Initialize observer systems if registered
        #[cfg(feature = "observer")]
        unsafe {
            crate::zend::observer::observer_startup();
            crate::zend::error_observer::error_observer_startup();
            crate::zend::exception_observer::exception_observer_startup();
            crate::zend::zend_extension::zend_extension_startup(&self.name, &self.version);
        }

        Ok(())
    }
}

/// A function to be called when the extension is starting up or shutting down.
pub type StartupShutdownFunc = unsafe extern "C" fn(_type: i32, _module_number: i32) -> i32;

/// A function to be called when `phpinfo();` is called.
pub type InfoFunc = unsafe extern "C" fn(zend_module: *mut ModuleEntry);

/// Builds a [`ModuleEntry`] and [`ModuleStartup`] from a [`ModuleBuilder`].
/// This is the entry point for the module to be registered with PHP.
impl TryFrom<ModuleBuilder<'_>> for (ModuleEntry, ModuleStartup) {
    type Error = crate::error::Error;

    fn try_from(builder: ModuleBuilder) -> Result<Self, Self::Error> {
        let mut functions = builder
            .functions
            .into_iter()
            .map(FunctionBuilder::build)
            .collect::<Result<Vec<_>>>()?;
        functions.push(FunctionEntry::end());
        let functions = Box::into_raw(functions.into_boxed_slice()) as *const FunctionEntry;

        #[cfg(feature = "observer")]
        let ext_name = builder.name.clone();
        #[cfg(feature = "observer")]
        let ext_version = builder.version.clone();

        let name = CString::new(builder.name)?.into_raw();
        let version = CString::new(builder.version)?.into_raw();

        let startup = ModuleStartup {
            #[cfg(feature = "observer")]
            name: ext_name,
            #[cfg(feature = "observer")]
            version: ext_version,
            constants: builder
                .constants
                .into_iter()
                .map(|(n, v, _)| (n, v))
                .collect(),
            classes: builder.classes,
            interfaces: builder.interfaces,
            #[cfg(feature = "enum")]
            enums: builder.enums,
        };

        #[cfg(not(php_zts))]
        let module_entry = ModuleEntry {
            size: mem::size_of::<ModuleEntry>().try_into()?,
            zend_api: ZEND_MODULE_API_NO,
            zend_debug: u8::from(PHP_DEBUG),
            zts: u8::from(PHP_ZTS),
            ini_entry: ptr::null(),
            deps: ptr::null(),
            name,
            functions,
            module_startup_func: builder.startup_func,
            module_shutdown_func: builder.shutdown_func,
            request_startup_func: builder.request_startup_func,
            request_shutdown_func: builder.request_shutdown_func,
            info_func: builder.info_func,
            version,
            globals_size: 0,
            globals_ptr: ptr::null_mut(),
            globals_ctor: None,
            globals_dtor: None,
            post_deactivate_func: builder.post_deactivate_func,
            module_started: 0,
            type_: 0,
            handle: ptr::null_mut(),
            module_number: 0,
            build_id: unsafe { ext_php_rs_php_build_id() },
        };

        #[cfg(php_zts)]
        let module_entry = ModuleEntry {
            size: mem::size_of::<ModuleEntry>().try_into()?,
            zend_api: ZEND_MODULE_API_NO,
            zend_debug: u8::from(PHP_DEBUG),
            zts: u8::from(PHP_ZTS),
            ini_entry: ptr::null(),
            deps: ptr::null(),
            name,
            functions,
            module_startup_func: builder.startup_func,
            module_shutdown_func: builder.shutdown_func,
            request_startup_func: builder.request_startup_func,
            request_shutdown_func: builder.request_shutdown_func,
            info_func: builder.info_func,
            version,
            globals_size: 0,
            globals_id_ptr: ptr::null_mut(),
            globals_ctor: None,
            globals_dtor: None,
            post_deactivate_func: builder.post_deactivate_func,
            module_started: 0,
            type_: 0,
            handle: ptr::null_mut(),
            module_number: 0,
            build_id: unsafe { ext_php_rs_php_build_id() },
        };

        Ok((module_entry, startup))
    }
}

#[cfg(test)]
mod tests {
    use crate::test::{
        test_deactivate_function, test_function, test_info_function, test_startup_shutdown_function,
    };

    use super::*;

    #[test]
    fn test_new() {
        let builder = ModuleBuilder::new("test", "1.0");
        assert_eq!(builder.name, "test");
        assert_eq!(builder.version, "1.0");
        assert!(builder.functions.is_empty());
        assert!(builder.constants.is_empty());
        assert!(builder.classes.is_empty());
        assert!(builder.interfaces.is_empty());
        assert!(builder.startup_func.is_none());
        assert!(builder.shutdown_func.is_none());
        assert!(builder.request_startup_func.is_none());
        assert!(builder.request_shutdown_func.is_none());
        assert!(builder.post_deactivate_func.is_none());
        assert!(builder.info_func.is_none());
        #[cfg(feature = "enum")]
        assert!(builder.enums.is_empty());
    }

    #[test]
    fn test_name() {
        let builder = ModuleBuilder::new("test", "1.0").name("new_test");
        assert_eq!(builder.name, "new_test");
    }

    #[test]
    fn test_version() {
        let builder = ModuleBuilder::new("test", "1.0").version("2.0");
        assert_eq!(builder.version, "2.0");
    }

    #[test]
    fn test_startup_function() {
        let builder =
            ModuleBuilder::new("test", "1.0").startup_function(test_startup_shutdown_function);
        assert!(builder.startup_func.is_some());
    }

    #[test]
    fn test_shutdown_function() {
        let builder =
            ModuleBuilder::new("test", "1.0").shutdown_function(test_startup_shutdown_function);
        assert!(builder.shutdown_func.is_some());
    }

    #[test]
    fn test_request_startup_function() {
        let builder = ModuleBuilder::new("test", "1.0")
            .request_startup_function(test_startup_shutdown_function);
        assert!(builder.request_startup_func.is_some());
    }

    #[test]
    fn test_request_shutdown_function() {
        let builder = ModuleBuilder::new("test", "1.0")
            .request_shutdown_function(test_startup_shutdown_function);
        assert!(builder.request_shutdown_func.is_some());
    }

    #[test]
    fn test_set_post_deactivate_function() {
        let builder =
            ModuleBuilder::new("test", "1.0").post_deactivate_function(test_deactivate_function);
        assert!(builder.post_deactivate_func.is_some());
    }

    #[test]
    fn test_set_info_function() {
        let builder = ModuleBuilder::new("test", "1.0").info_function(test_info_function);
        assert!(builder.info_func.is_some());
    }

    #[test]
    fn test_add_function() {
        let builder =
            ModuleBuilder::new("test", "1.0").function(FunctionBuilder::new("test", test_function));
        assert_eq!(builder.functions.len(), 1);
    }

    #[test]
    #[cfg(feature = "embed")]
    fn test_add_constant() {
        let builder =
            ModuleBuilder::new("test", "1.0").constant(("TEST_CONST", 42, DocComments::default()));
        assert_eq!(builder.constants.len(), 1);
        assert_eq!(builder.constants[0].0, "TEST_CONST");
        // TODO: Check if the value is 42
        assert_eq!(builder.constants[0].2, DocComments::default());
    }
}