add missing test case for empty transparent struct

mozilla · Aug 12, 2024 · f6d956d · f6d956d
1 parent ba96d90
commit f6d956d
Show file tree

Hide file tree

Showing 11 changed files with 67 additions and 18 deletions.
diff --git a/src/bindgen/ir/structure.rs b/src/bindgen/ir/structure.rs
@@ -153,16 +153,16 @@ impl Struct {
     /// Attempts to convert this struct to a typedef (only works for transparent structs).
     pub fn as_typedef(&self) -> Option<Typedef> {
         if self.is_transparent {
-            // NOTE: A `#[repr(transparent)]` struct with 2+ NZT fields fails to compile, but 0
-            // fields is allowed for some strange reason. Don't emit the typedef in that case.
+            // NOTE: The rust compiler rejects a `#[repr(transparent)]` struct with 2+ NZST fields,
+            // but accepts an empty struct (see https://github.com/rust-lang/rust/issues/129029).
+            // Don't emit the typedef in that case.
             if let Some(field) = self.fields.first() {
                 return Some(Typedef::new_from_struct_field(self, field));
-            } else {
-                error!(
-                    "Cannot convert empty transparent struct {} to typedef",
-                    self.name()
-                );
             }
+            error!(
+                "Cannot convert empty transparent struct {} to typedef",
+                self.name()
+            );
         }
         None
     }
@@ -288,7 +288,7 @@ impl Item for Struct {
     }
 
     fn collect_declaration_types(&self, resolver: &mut DeclarationTypeResolver) {
-        if self.is_transparent {
+        if self.is_transparent && self.fields.len() == 1 {
             resolver.add_none(&self.path);
         } else {
             resolver.add_struct(&self.path);

diff --git a/tests/expectations/transparent.c b/tests/expectations/transparent.c
@@ -23,6 +23,10 @@ typedef uint32_t TransparentPrimitiveWithAssociatedConstants;
 #define TransparentPrimitiveWithAssociatedConstants_ZERO 0
 #define TransparentPrimitiveWithAssociatedConstants_ONE 1
 
+typedef struct {
+
+} TransparentEmptyStructure;
+
 #define EnumWithAssociatedConstantInImpl_TEN 10
 
 void root(TransparentComplexWrappingStructTuple a,
@@ -32,4 +36,5 @@ void root(TransparentComplexWrappingStructTuple a,
           TransparentComplexWrapper_i32 e,
           TransparentPrimitiveWrapper_i32 f,
           TransparentPrimitiveWithAssociatedConstants g,
-          EnumWithAssociatedConstantInImpl h);
+          TransparentEmptyStructure h,
+          EnumWithAssociatedConstantInImpl i);
diff --git a/tests/expectations/transparent.compat.c b/tests/expectations/transparent.compat.c
@@ -23,6 +23,10 @@ typedef uint32_t TransparentPrimitiveWithAssociatedConstants;
 #define TransparentPrimitiveWithAssociatedConstants_ZERO 0
 #define TransparentPrimitiveWithAssociatedConstants_ONE 1
 
+typedef struct {
+
+} TransparentEmptyStructure;
+
 #define EnumWithAssociatedConstantInImpl_TEN 10
 
 #ifdef __cplusplus
@@ -36,7 +40,8 @@ void root(TransparentComplexWrappingStructTuple a,
           TransparentComplexWrapper_i32 e,
           TransparentPrimitiveWrapper_i32 f,
           TransparentPrimitiveWithAssociatedConstants g,
-          EnumWithAssociatedConstantInImpl h);
+          TransparentEmptyStructure h,
+          EnumWithAssociatedConstantInImpl i);
 
 #ifdef __cplusplus
 }  // extern "C"

diff --git a/tests/expectations/transparent.cpp b/tests/expectations/transparent.cpp
@@ -26,6 +26,10 @@ using TransparentPrimitiveWithAssociatedConstants = uint32_t;
 constexpr static const TransparentPrimitiveWithAssociatedConstants TransparentPrimitiveWithAssociatedConstants_ZERO = 0;
 constexpr static const TransparentPrimitiveWithAssociatedConstants TransparentPrimitiveWithAssociatedConstants_ONE = 1;
 
+struct TransparentEmptyStructure {
+
+};
+
 constexpr static const TransparentPrimitiveWrappingStructure EnumWithAssociatedConstantInImpl_TEN = 10;
 
 extern "C" {
@@ -37,6 +41,7 @@ void root(TransparentComplexWrappingStructTuple a,
           TransparentComplexWrapper<int32_t> e,
           TransparentPrimitiveWrapper<int32_t> f,
           TransparentPrimitiveWithAssociatedConstants g,
-          EnumWithAssociatedConstantInImpl h);
+          TransparentEmptyStructure h,
+          EnumWithAssociatedConstantInImpl i);
 
 }  // extern "C"
diff --git a/tests/expectations/transparent.pyx b/tests/expectations/transparent.pyx
@@ -28,6 +28,9 @@ cdef extern from *:
   const TransparentPrimitiveWithAssociatedConstants TransparentPrimitiveWithAssociatedConstants_ZERO # = 0
   const TransparentPrimitiveWithAssociatedConstants TransparentPrimitiveWithAssociatedConstants_ONE # = 1
 
+  ctypedef struct TransparentEmptyStructure:
+    pass
+
   const TransparentPrimitiveWrappingStructure EnumWithAssociatedConstantInImpl_TEN # = 10
 
   void root(TransparentComplexWrappingStructTuple a,
@@ -37,4 +40,5 @@ cdef extern from *:
             TransparentComplexWrapper_i32 e,
             TransparentPrimitiveWrapper_i32 f,
             TransparentPrimitiveWithAssociatedConstants g,
-            EnumWithAssociatedConstantInImpl h);
+            TransparentEmptyStructure h,
+            EnumWithAssociatedConstantInImpl i);
diff --git a/tests/expectations/transparent_both.c b/tests/expectations/transparent_both.c
@@ -23,6 +23,10 @@ typedef uint32_t TransparentPrimitiveWithAssociatedConstants;
 #define TransparentPrimitiveWithAssociatedConstants_ZERO 0
 #define TransparentPrimitiveWithAssociatedConstants_ONE 1
 
+typedef struct TransparentEmptyStructure {
+
+} TransparentEmptyStructure;
+
 #define EnumWithAssociatedConstantInImpl_TEN 10
 
 void root(TransparentComplexWrappingStructTuple a,
@@ -32,4 +36,5 @@ void root(TransparentComplexWrappingStructTuple a,
           TransparentComplexWrapper_i32 e,
           TransparentPrimitiveWrapper_i32 f,
           TransparentPrimitiveWithAssociatedConstants g,
-          struct EnumWithAssociatedConstantInImpl h);
+          struct TransparentEmptyStructure h,
+          struct EnumWithAssociatedConstantInImpl i);
diff --git a/tests/expectations/transparent_both.compat.c b/tests/expectations/transparent_both.compat.c
@@ -23,6 +23,10 @@ typedef uint32_t TransparentPrimitiveWithAssociatedConstants;
 #define TransparentPrimitiveWithAssociatedConstants_ZERO 0
 #define TransparentPrimitiveWithAssociatedConstants_ONE 1
 
+typedef struct TransparentEmptyStructure {
+
+} TransparentEmptyStructure;
+
 #define EnumWithAssociatedConstantInImpl_TEN 10
 
 #ifdef __cplusplus
@@ -36,7 +40,8 @@ void root(TransparentComplexWrappingStructTuple a,
           TransparentComplexWrapper_i32 e,
           TransparentPrimitiveWrapper_i32 f,
           TransparentPrimitiveWithAssociatedConstants g,
-          struct EnumWithAssociatedConstantInImpl h);
+          struct TransparentEmptyStructure h,
+          struct EnumWithAssociatedConstantInImpl i);
 
 #ifdef __cplusplus
 }  // extern "C"

diff --git a/tests/expectations/transparent_tag.c b/tests/expectations/transparent_tag.c
@@ -23,6 +23,10 @@ typedef uint32_t TransparentPrimitiveWithAssociatedConstants;
 #define TransparentPrimitiveWithAssociatedConstants_ZERO 0
 #define TransparentPrimitiveWithAssociatedConstants_ONE 1
 
+struct TransparentEmptyStructure {
+
+};
+
 #define EnumWithAssociatedConstantInImpl_TEN 10
 
 void root(TransparentComplexWrappingStructTuple a,
@@ -32,4 +36,5 @@ void root(TransparentComplexWrappingStructTuple a,
           TransparentComplexWrapper_i32 e,
           TransparentPrimitiveWrapper_i32 f,
           TransparentPrimitiveWithAssociatedConstants g,
-          struct EnumWithAssociatedConstantInImpl h);
+          struct TransparentEmptyStructure h,
+          struct EnumWithAssociatedConstantInImpl i);
diff --git a/tests/expectations/transparent_tag.compat.c b/tests/expectations/transparent_tag.compat.c
@@ -23,6 +23,10 @@ typedef uint32_t TransparentPrimitiveWithAssociatedConstants;
 #define TransparentPrimitiveWithAssociatedConstants_ZERO 0
 #define TransparentPrimitiveWithAssociatedConstants_ONE 1
 
+struct TransparentEmptyStructure {
+
+};
+
 #define EnumWithAssociatedConstantInImpl_TEN 10
 
 #ifdef __cplusplus
@@ -36,7 +40,8 @@ void root(TransparentComplexWrappingStructTuple a,
           TransparentComplexWrapper_i32 e,
           TransparentPrimitiveWrapper_i32 f,
           TransparentPrimitiveWithAssociatedConstants g,
-          struct EnumWithAssociatedConstantInImpl h);
+          struct TransparentEmptyStructure h,
+          struct EnumWithAssociatedConstantInImpl i);
 
 #ifdef __cplusplus
 }  // extern "C"

diff --git a/tests/expectations/transparent_tag.pyx b/tests/expectations/transparent_tag.pyx
@@ -28,6 +28,9 @@ cdef extern from *:
   const TransparentPrimitiveWithAssociatedConstants TransparentPrimitiveWithAssociatedConstants_ZERO # = 0
   const TransparentPrimitiveWithAssociatedConstants TransparentPrimitiveWithAssociatedConstants_ONE # = 1
 
+  cdef struct TransparentEmptyStructure:
+    pass
+
   const TransparentPrimitiveWrappingStructure EnumWithAssociatedConstantInImpl_TEN # = 10
 
   void root(TransparentComplexWrappingStructTuple a,
@@ -37,4 +40,5 @@ cdef extern from *:
             TransparentComplexWrapper_i32 e,
             TransparentPrimitiveWrapper_i32 f,
             TransparentPrimitiveWithAssociatedConstants g,
-            EnumWithAssociatedConstantInImpl h);
+            TransparentEmptyStructure h,
+            EnumWithAssociatedConstantInImpl i);
diff --git a/tests/rust/transparent.rs b/tests/rust/transparent.rs
@@ -41,6 +41,11 @@ impl TransparentPrimitiveWithAssociatedConstants {
 #[repr(transparent)]
 struct TransparentPrimitiveWithAssociatedConstants { bits: u32 }
 
+// https://github.com/rust-lang/rust/issues/129029 the rust compiler (wrongly?) accepts this, but
+// cbindgen should nevertheless emit the struct definition instead of a typedef.
+#[repr(transparent)]
+struct TransparentEmptyStructure;
+
 // Associated constant declared after struct declaration.
 impl TransparentPrimitiveWithAssociatedConstants {
     pub const ONE: TransparentPrimitiveWithAssociatedConstants = TransparentPrimitiveWithAssociatedConstants {
@@ -63,5 +68,6 @@ pub extern "C" fn root(
     e: TransparentComplexWrapper<i32>,
     f: TransparentPrimitiveWrapper<i32>,
     g: TransparentPrimitiveWithAssociatedConstants,
-    h: EnumWithAssociatedConstantInImpl,
+    h: TransparentEmptyStructure,
+    i: EnumWithAssociatedConstantInImpl,
 ) { }