Split disguised attribute into two

The disguised attribute started off as a way to indicate a typedef to a
structure pointer, e.g.

    typedef struct Foo* FooPtr;

Over the years, though, it started to include opaque structure types,
e.g.

    typedef struct _FooObject FooObject;
    typedef struct _FooObjectClass FooObjectClass;

This has led to issues in language bindings, code generators, and
documentation generators, which now have issues when dealing with both
pointer aliases and opaque types.

An initial attempt at fixing this mess in commit f606183a ended up
breaking Vala, and had to be reverted.

To avoid breaking existing users we can follow a similar approach to the
allow-none/nullable/optional solution:

1. introduce a new pair of attributes: "pointer" and "opaque"
2. deprecate the "disguised" attribute

The "pointer" attribute covers the case of pointer types.

The "opaque" attribute covers the case of opaque structured types.

See also: https://gitlab.gnome.org/GNOME/vala/-/issues/735

Fixes: #101

1 files changed, 17 insertions, 10 deletions

diff --git a/giscanner/transformer.py b/giscanner/transformer.py
index ad2a87f4..3b0bea8a 100644
--- a/giscanner/transformer.py
+++ b/giscanner/transformer.py
@@ -613,7 +613,7 @@ raise ValueError."""
         elif (ctype == CTYPE_FUNCTION):
             node = self._create_typedef_callback(symbol)
         elif (ctype == CTYPE_POINTER and symbol.base_type.base_type.type == CTYPE_STRUCT):
-            node = self._create_typedef_compound(ast.Record, symbol, disguised=True)
+            node = self._create_typedef_compound(ast.Record, symbol, disguised=True, pointer=True)
         elif ctype == CTYPE_STRUCT:
             node = self._create_typedef_compound(ast.Record, symbol)
         elif ctype == CTYPE_UNION:
@@ -801,7 +801,7 @@ raise ValueError."""
         const.add_symbol_reference(symbol)
         return const
 
-    def _create_typedef_compound(self, compound_class, symbol, disguised=False):
+    def _create_typedef_compound(self, compound_class, symbol, disguised=False, pointer=False):
         name = self.strip_identifier(symbol.ident)
         assert symbol.base_type
         if symbol.base_type.name:
@@ -840,12 +840,14 @@ raise ValueError."""
             # Structs with a typedef name are promoted into the main namespace
             # by it being returned to the "parse" function and are also added to
             # the tag namespace if it has a tag_name set.
-            compound = compound_class(name, symbol.ident, disguised=disguised, tag_name=tag_name)
+            compound = compound_class(name, symbol.ident, disguised=disguised, pointer=pointer, tag_name=tag_name)
             if tag_name:
-                # Force the struct as disguised for now since we do not yet know
-                # if it has fields that will be parsed. Note that this is using
-                # an erroneous definition of disguised and we should eventually
-                # only look at the field count when needed.
+                # Force the struct as opaque for now since we do not yet know
+                # if it has fields that will be parsed.
+                compound.opaque = True
+                # Set disguised as well, for backward compatibility; the "disguised" field
+                # is used incorrectly, here, but it's too late for us to change this. See
+                # https://gitlab.gnome.org/GNOME/gobject-introspection/-/issues/101
                 compound.disguised = True
             else:
                 # Case where we have an anonymous struct which is typedef'd:
@@ -864,12 +866,17 @@ raise ValueError."""
         else:
             compound = compound_class(None, symbol.ident, tag_name=symbol.ident)
 
-        # Make sure disguised is False as we are now about to parse the
-        # fields of the real struct.
-        compound.disguised = False
         # Fields may need to be parsed in either of the above cases because the
         # Record can be created with a typedef prior to the struct definition.
         self._parse_fields(symbol, compound)
+
+        # A compound type with no fields is opaque
+        compound.opaque = len(compound.fields) == 0
+        # Unconditionally set disguised to false, for backward compatibility;
+        # the "disguised" field is used incorrectly, here, but it's too late for
+        # us to change this. See:
+        #   https://gitlab.gnome.org/GNOME/gobject-introspection/-/issues/101
+        compound.disguised = False
         compound.add_symbol_reference(symbol)
         return compound