add null_progress function

Author: mdekstrand

docs/api.rst

@@ -11,6 +11,8 @@ Creating Progress Bars
 
 .. autofunction:: make_progress
 
+.. autofunction:: null_progress
+
 Progress Bar Interface
 ----------------------
 

progress_api/api.py

@@ -25,7 +25,6 @@ class Progress(ABC):
     """
 
     name: str
-    spec: backends.ProgressBarSpec
 
     @abstractmethod
     def set_label(self, label: Optional[str]) -> None:
@@ -147,3 +146,14 @@ def make_progress(
 
     spec = backends.ProgressBarSpec(logger, label, total, unit, sl, leave)
     return config.get_backend().create_bar(spec)
+
+
+def null_progress() -> Progress:
+    """
+    Create a null progress bar, regardless of the configured backend. This is
+    useful to allow progress reporting to be optional without littering code
+    with conditionals.
+    """
+    from progress_api.backends.null import NullProgress
+
+    return NullProgress()

progress_api/backends/enlighten.py

@@ -51,6 +51,7 @@ class EnlightenProgressBackend(ProgressBackend):
     Progress bar backend that doesn't emit any progress.
     """
 
+    spec: ProgressBarSpec
     manager: Manager
     state_colors: dict[str, str]
 

progress_api/backends/mock.py

@@ -32,6 +32,7 @@ def create_bar(self, spec: ProgressBarSpec) -> api.Progress:
 
 
 class MockProgress(api.Progress):
+    spec: ProgressBarSpec
     backend: MockProgressBackend
 
     def __init__(self, backend: MockProgressBackend, spec: ProgressBarSpec):

progress_api/backends/null.py

@@ -21,13 +21,10 @@ class NullProgressBackend(ProgressBackend):
     """
 
     def create_bar(self, spec: ProgressBarSpec) -> api.Progress:
-        return NullProgress(spec)
+        return NullProgress()
 
 
 class NullProgress(api.Progress):
-    def __init__(self, spec: ProgressBarSpec):
-        self.spec = spec
-
     def set_label(self, label: Optional[str]):
         pass