interpreter: deprecate the ability import unstable modules as `unstable_*`

This was never meant to work, it's an implementation detail of using
`importlib.import_module` and that our modules used to be named
`unstable_` that this ever worked.

3 files changed, 7 insertions, 0 deletions

diff --git a/mesonbuild/interpreter/interpreter.py b/mesonbuild/interpreter/interpreter.py
index 9cf88d7..5752d4c 100644
--- a/mesonbuild/interpreter/interpreter.py
+++ b/mesonbuild/interpreter/interpreter.py
@@ -617,6 +617,9 @@ class Interpreter(InterpreterBase, HoldableObject):
         # Some tests use "unstable_" instead of "unstable-", and that happens to work because
         # of implementation details
         if modname.startswith(('unstable-', 'unstable_')):
+            if modname.startswith('unstable_'):
+                mlog.deprecation(f'Importing unstable modules as "{modname}" instead of "{modname.replace("_", "-", 1)}"',
+                                 location=node)
             real_modname = modname[len('unstable') + 1:]  # + 1 to handle the - or _
             expect_unstable = True
         else:
diff --git a/test cases/common/253 module warnings/meson.build b/test cases/common/253 module warnings/meson.build
index 8397930..56e2055 100644
--- a/test cases/common/253 module warnings/meson.build
+++ b/test cases/common/253 module warnings/meson.build
@@ -3,6 +3,7 @@ project('module warnings', meson_version : '>= 0.56')
 import('python3')          # deprecated module
 import('java')             # new module
 import('unstable-keyval')  # module that has been stabilized, import with unstable-
+import('unstable_simd')    # A module with the deprecated `unstable_foo` instead of `unstable-foo`
 
 ice = import('icestorm', required : false)
 assert(not ice.found(), 'unstable-icestorm module should not be importable as `simd`')
diff --git a/test cases/common/253 module warnings/test.json b/test cases/common/253 module warnings/test.json
index ec861cc..be31601 100644
--- a/test cases/common/253 module warnings/test.json
+++ b/test cases/common/253 module warnings/test.json
@@ -8,6 +8,9 @@
     },
     {
       "line": "test cases/common/253 module warnings/meson.build:5: WARNING: Project targets '>= 0.56' but uses feature deprecated since '0.56.0': module keyval has been stabilized. drop \"unstable-\" prefix from the module name"
+    },
+    {
+      "line": "test cases/common/253 module warnings/meson.build:6: DEPRECATION: Importing unstable modules as \"unstable_simd\" instead of \"unstable-simd\""
     }
   ]
 }