environment: build_dir is allowed to be None in the initializer

But we really expect it to be a string once the initializer is done.
Therefore, let's set it to `''` just like we do with the scratchdir in
the case that it's set to None in the initializer.

1 files changed, 3 insertions, 2 deletions

diff --git a/mesonbuild/environment.py b/mesonbuild/environment.py
index 92ce9c5..a0d98ae 100644
--- a/mesonbuild/environment.py
+++ b/mesonbuild/environment.py
@@ -566,12 +566,12 @@ class Environment:
     log_dir = 'meson-logs'
     info_dir = 'meson-info'
 
-    def __init__(self, source_dir: str, build_dir: str, cmd_options: coredata.SharedCMDOptions) -> None:
+    def __init__(self, source_dir: str, build_dir: T.Optional[str], cmd_options: coredata.SharedCMDOptions) -> None:
         self.source_dir = source_dir
-        self.build_dir = build_dir
         # Do not try to create build directories when build_dir is none.
         # This reduced mode is used by the --buildoptions introspector
         if build_dir is not None:
+            self.build_dir = build_dir
             self.scratch_dir = os.path.join(build_dir, Environment.private_dir)
             self.log_dir = os.path.join(build_dir, Environment.log_dir)
             self.info_dir = os.path.join(build_dir, Environment.info_dir)
@@ -600,6 +600,7 @@ class Environment:
                     raise MesonException(f'{str(e)} Try regenerating using "meson setup --wipe".')
         else:
             # Just create a fresh coredata in this case
+            self.build_dir = ''
             self.scratch_dir = ''
             self.create_new_coredata(cmd_options)