Harmonize d_import_dirs and include_directories behavior.

This commit harmonizes the handling of `d_import_dirs` and
`include_directories`. The treatment of `d_import_dirs` was also
different depending on the context: in `declare_dependency` it was
treated like the `include_directories`, but in `build_target` et al,
it had special treatment. With this commit, they are all treated
by the same function. The documentation has been updated to
reflect this.

Fixes mesonbuild#12742

docs/yaml/functions/_build_target_base.yaml

@@ -256,8 +256,11 @@ kwargs:
       do not support GNU visibility arguments.
 
   d_import_dirs:
-    type: list[str]
-    description: List of directories to look in for string imports used in the D programming language.
+    type: list[inc | str]
+    since: 0.62.0
+    description: |
+      the directories to add to the string search path (i.e. `-J` switch for DMD).
+      Must be [[@inc]] objects or plain strings.
 
   d_unittest:
     type: bool

mesonbuild/interpreter/interpreter.py

@@ -2801,6 +2801,12 @@ def extract_incdirs(self, kwargs, key: str = 'include_directories') -> T.List[bu
             if isinstance(p, build.IncludeDirs):
                 result.append(p)
             elif isinstance(p, str):
+                if key == 'd_import_dirs' and os.path.normpath(p).startswith(self.environment.get_source_dir()):
+                    FeatureDeprecated.single_use('Building absolute path to source dir is not supported',
+                                                 '0.45', self.subproject,
+                                                 'Use a relative path instead.',
+                                                 location=self.current_node)
+                    p = os.path.relpath(p, os.path.join(self.environment.get_source_dir(), self.subdir))
                 result.append(self.build_incdir_object([p]))
             else:
                 raise InterpreterException('Include directory objects can only be created from strings or include directories.')
@@ -3400,7 +3406,7 @@ def build_target(self, node: mparser.BaseNode, args: T.Tuple[str, SourcesVarargs
                 kwargs['language_args'][lang].extend(args)
                 kwargs['depend_files'].extend(deps)
         if targetclass is not build.Jar:
-            self.kwarg_strings_to_includedirs(kwargs)
+            kwargs['d_import_dirs'] = self.extract_incdirs(kwargs, 'd_import_dirs')
 
         # Filter out kwargs from other target types. For example 'soversion'
         # passed to library() when default_library == 'static'.
@@ -3473,23 +3479,6 @@ def build_target(self, node: mparser.BaseNode, args: T.Tuple[str, SourcesVarargs
         self.project_args_frozen = True
         return target
 
-    def kwarg_strings_to_includedirs(self, kwargs: kwtypes._BuildTarget) -> None:
-        if kwargs['d_import_dirs']:
-            items = kwargs['d_import_dirs']
-            cleaned_items: T.List[build.IncludeDirs] = []
-            for i in items:
-                if isinstance(i, str):
-                    # BW compatibility. This was permitted so we must support it
-                    # for a few releases so people can transition to "correct"
-                    # path declarations.
-                    if os.path.normpath(i).startswith(self.environment.get_source_dir()):
-                        mlog.warning('''Building a path to the source dir is not supported. Use a relative path instead.
-This will become a hard error in the future.''', location=self.current_node)
-                        i = os.path.relpath(i, os.path.join(self.environment.get_source_dir(), self.subdir))
-                        i = self.build_incdir_object([i])
-                cleaned_items.append(i)
-            kwargs['d_import_dirs'] = cleaned_items
-
     def add_stdlib_info(self, target):
         for l in target.compilers.keys():
             dep = self.build.stdlibs[target.for_machine].get(l, None)

test cases/d/9 features/meson.build

@@ -1,4 +1,4 @@
-project('D Features', 'd', default_options : ['debug=false'])
+project('D Features', 'd', meson_version: '>=1.6', default_options : ['debug=false'])
 
 dc = meson.get_compiler('d')