interpreter: Iterate custom target outputs

docs/markdown/Reference-manual.md

@@ -2299,6 +2299,8 @@ contains a target with the following methods:
   NOTE: In most cases using the object itself will do the same job as
   this and will also allow Meson to setup inter-target dependencies
   correctly. Please file a bug if that doesn't work for you.
+  *Since 0.54.0* it can be also called on indexes objects:
+  `custom_targets[i].full_path()`.
 
 - `[index]` returns an opaque object that references this target, and
   can be used as a source in other targets. When it is used as such it
@@ -2306,6 +2308,10 @@ contains a target with the following methods:
   source added will be the one that corresponds to the index of the
   custom target's output argument.
 
+- `to_list()` *Since 0.54.0*, returns a list of opaque objects that references
+  this target, and can be used as a source in other targets. This can be used to
+  iterate outputs with `foreach` loop.
+
 ### `dependency` object
 
 This object is returned by [`dependency()`](#dependency) and contains

mesonbuild/build.py

@@ -2250,6 +2250,10 @@ class CustomTarget(Target):
     def __delitem__(self, index):
         raise NotImplementedError
 
+    def __iter__(self):
+        for i in self.outputs:
+            yield CustomTargetIndex(self, i)
+
 class RunTarget(Target):
     def __init__(self, name, command, args, dependencies, subdir, subproject):
         self.typename = 'run'

mesonbuild/interpreter.py

@@ -871,15 +871,23 @@ class JarHolder(BuildTargetHolder):
     def __init__(self, target, interp):
         super().__init__(target, interp)
 
-class CustomTargetIndexHolder(InterpreterObject, ObjectHolder):
-    def __init__(self, object_to_hold):
-        InterpreterObject.__init__(self)
-        ObjectHolder.__init__(self, object_to_hold)
+class CustomTargetIndexHolder(TargetHolder):
+    def __init__(self, target, interp):
+        super().__init__(target, interp)
+        self.methods.update({'full_path': self.full_path_method,
+                             })
+
+    @FeatureNew('custom_target[i].full_path', '0.54.0')
+    @noPosargs
+    @permittedKwargs({})
+    def full_path_method(self, args, kwargs):
+        return self.interpreter.backend.get_target_filename_abs(self.held_object)
 
 class CustomTargetHolder(TargetHolder):
     def __init__(self, target, interp):
         super().__init__(target, interp)
         self.methods.update({'full_path': self.full_path_method,
+                             'to_list': self.to_list_method,
                              })
 
     def __repr__(self):
@@ -892,8 +900,17 @@ class CustomTargetHolder(TargetHolder):
     def full_path_method(self, args, kwargs):
         return self.interpreter.backend.get_target_filename_abs(self.held_object)
 
+    @FeatureNew('custom_target.to_list', '0.54.0')
+    @noPosargs
+    @permittedKwargs({})
+    def to_list_method(self, args, kwargs):
+        result = []
+        for i in self.held_object:
+            result.append(CustomTargetIndexHolder(i, self.interpreter))
+        return result
+
     def __getitem__(self, index):
-        return CustomTargetIndexHolder(self.held_object[index])
+        return CustomTargetIndexHolder(self.held_object[index], self.interpreter)
 
     def __setitem__(self, index, value):  # lgtm[py/unexpected-raise-in-special-method]
         raise InterpreterException('Cannot set a member of a CustomTarget')

test cases/common/144 custom target multiple outputs/meson.build

@@ -21,8 +21,19 @@ custom_target('only-install-first',
   install : true,
   install_dir : [join_paths(get_option('prefix'), get_option('includedir')), false])
 
-custom_target('only-install-second',
+targets = custom_target('only-install-second',
   output : ['second.h', 'second.sh'],
   command : [gen, 'second', '@OUTDIR@'],
   install : true,
   install_dir : [false, join_paths(get_option('prefix'), get_option('bindir'))])
+
+paths = []
+foreach i : targets.to_list()
+  paths += i.full_path()
+endforeach
+
+# Skip on Windows because paths are not identical, '/' VS '\'.
+if host_machine.system() != 'windows'
+  assert(paths == [meson.current_build_dir() / 'second.h',
+                   meson.current_build_dir() / 'second.sh'])
+endif