Fix linking issue when video module is used without tracking

Author: twistedfall

binding-generator/src/entity.rs

@@ -77,6 +77,7 @@ pub trait EntityExt<'tu> {
 	fn walk_fields_while(&self, predicate: impl FnMut(Entity<'tu>) -> ControlFlow<()>) -> ControlFlow<()>;
 	fn walk_consts_while(&self, predicate: impl FnMut(Entity<'tu>) -> ControlFlow<()>) -> ControlFlow<()>;
 	fn walk_methods_while(&self, predicate: impl FnMut(Entity<'tu>) -> ControlFlow<()>) -> ControlFlow<()>;
+	fn walk_parents<T>(&self, predicate: impl FnMut(Entity<'tu>) -> ControlFlow<T>) -> ControlFlow<T>;
 }
 
 impl<'tu> EntityExt<'tu> for Entity<'tu> {
@@ -149,6 +150,17 @@ impl<'tu> EntityExt<'tu> for Entity<'tu> {
 			_ => ControlFlow::Continue(()),
 		})
 	}
+
+	fn walk_parents<T>(&self, mut predicate: impl FnMut(Entity<'tu>) -> ControlFlow<T>) -> ControlFlow<T> {
+		let mut current = *self;
+		while let Some(parent) = current.get_semantic_parent() {
+			match predicate(parent) {
+				ControlFlow::Continue(()) => current = parent,
+				ControlFlow::Break(out) => return ControlFlow::Break(out),
+			}
+		}
+		ControlFlow::Continue(())
+	}
 }
 
 #[allow(unused)]

binding-generator/src/writer/rust_native/element.rs

@@ -1,13 +1,14 @@
 use std::borrow::Cow;
 use std::fmt::Debug;
+use std::ops::ControlFlow;
 
 use clang::{Entity, EntityKind};
 
 use super::comment::RenderComment;
 use crate::type_ref::FishStyle;
 use crate::{
-	opencv_module_from_path, reserved_rename, settings, CppNameStyle, Element, GeneratedType, IteratorExt, NameStyle, StringExt,
-	SupportedModule,
+	opencv_module_from_path, reserved_rename, settings, CppNameStyle, Element, EntityExt, GeneratedType, IteratorExt, NameStyle,
+	StringExt, SupportedModule,
 };
 
 pub struct DefaultRustNativeElement;
@@ -20,7 +21,7 @@ impl DefaultRustNativeElement {
 			.get_spelling_location()
 			.file
 			.and_then(|file| opencv_module_from_path(&file.get_path()))
-			.unwrap_or(SupportedModule::Core)
+			.map_or(SupportedModule::Core, |m| rust_module_hack(entity, m))
 	}
 
 	pub fn rust_module_reference(this: &(impl RustElement + ?Sized)) -> Cow<'_, str> {
@@ -148,3 +149,28 @@ impl<'ne, 'tu: 'ne, 'ge: 'ne> AsRef<dyn RustNativeGeneratedElement + 'ne> for Ge
 		}
 	}
 }
+
+/// Adjusts the module for certain entities that are technically in one module but actually implemented in another.
+///
+/// One (and for now the only) example is that some class declarations are technically in `hpp` files in the `video` module, but
+/// their code is actually in the `tracking` module of `opencv_contrib`. This mismatch leads to linking errors if only the
+/// `opencv_video` module is linked.
+fn rust_module_hack(entity: Entity, module_from_path: SupportedModule) -> SupportedModule {
+	match module_from_path {
+		SupportedModule::Video => {
+			let break_res = entity.walk_parents(|parent| match parent.get_kind() {
+				EntityKind::Namespace if parent.is_inline_namespace() && parent.get_name().is_some_and(|n| n == "tracking") => {
+					ControlFlow::Break(SupportedModule::Tracking)
+				}
+				_ => ControlFlow::Continue(()),
+			});
+			// todo: MSRV 1.83 use `break_value()`
+			match break_res {
+				ControlFlow::Break(m) => Some(m),
+				ControlFlow::Continue(_) => None,
+			}
+			.unwrap_or(module_from_path)
+		}
+		_ => module_from_path,
+	}
+}

binding-generator/src/writer/rust_native/mod.rs

@@ -117,7 +117,11 @@ impl<'s> RustNativeBindingWriter<'s> {
 
 impl GeneratorVisitor<'_> for RustNativeBindingWriter<'_> {
 	fn wants_file(&mut self, path: &Path) -> bool {
-		opencv_module_from_path(path) == Some(self.module)
+		match self.module {
+			// tracking_legacy.hpp includes header from the video module, but we need those definitions in the tracking module
+			SupportedModule::Tracking if path.ends_with("video/detail/tracking.detail.hpp") => true,
+			_ => opencv_module_from_path(path) == Some(self.module),
+		}
 	}
 
 	fn visit_module_comment(&mut self, comment: String) {