install debug into builtins via DebugProxy (#139)

Author: samuelcolvin

Makefile

@@ -25,7 +25,7 @@ update-lockfiles:
 .PHONY: format
 format:
 	black $(sources)
-	ruff $(sources) --fix --exit-zero
+	ruff $(sources) --fix-only
 
 .PHONY: lint
 lint:

devtools/__main__.py

@@ -7,17 +7,32 @@
 # language=python
 install_code = """
 # add devtools `debug` function to builtins
-import sys
-# we don't install here for pytest as it breaks pytest, it is
-# installed later by a pytest fixture
-if not sys.argv[0].endswith('pytest'):
-    import builtins
-    try:
-        from devtools import debug
-    except ImportError:
-        pass
-    else:
-        setattr(builtins, 'debug', debug)
+# we don't want to import devtools until it's required since it breaks pytest, hence this proxy
+class DebugProxy:
+    def __init__(self):
+        self._debug = None
+
+    def _import_debug(self):
+        if self._debug is None:
+            from devtools import debug
+            self._debug = debug
+
+    def __call__(self, *args, **kwargs):
+        self._import_debug()
+        kwargs['frame_depth_'] = 3
+        return self._debug(*args, **kwargs)
+
+    def format(self, *args, **kwargs):
+        self._import_debug()
+        kwargs['frame_depth_'] = 3
+        return self._debug.format(*args, **kwargs)
+
+    def __getattr__(self, item):
+        self._import_debug()
+        return getattr(self._debug, item)
+
+import builtins
+setattr(builtins, 'debug', DebugProxy())
 """
 
 
@@ -27,12 +42,6 @@ def print_code() -> int:
 
 
 def install() -> int:
-    print('[WARNING: this command is experimental, report issues at github.com/samuelcolvin/python-devtools]\n')
-
-    if hasattr(builtins, 'debug'):
-        print('Looks like devtools is already installed.')
-        return 0
-
     try:
         import sitecustomize  # type: ignore
     except ImportError:
@@ -48,7 +57,11 @@ def install() -> int:
     else:
         install_path = Path(sitecustomize.__file__)
 
-    print(f'Found path "{install_path}" to install devtools into __builtins__')
+    if hasattr(builtins, 'debug'):
+        print(f'Looks like devtools is already installed, probably in `{install_path}`.')
+        return 0
+
+    print(f'Found path `{install_path}` to install devtools into `builtins`')
     print('To install devtools, run the following command:\n')
     print(f'    python -m devtools print-code >> {install_path}\n')
     if not install_path.is_relative_to(Path.home()):
@@ -65,5 +78,5 @@ def install() -> int:
     elif 'print-code' in sys.argv:
         sys.exit(print_code())
     else:
-        print(f'python-devtools v{VERSION}, CLI usage: python -m devtools [install|print-code]')
+        print(f'python-devtools v{VERSION}, CLI usage: `python -m devtools install|print-code`')
         sys.exit(1)

devtools/debug.py

@@ -112,8 +112,15 @@ def __init__(self, *, warnings: 'Optional[bool]' = None, highlight: 'Optional[bo
         self._show_warnings = env_bool(warnings, 'PY_DEVTOOLS_WARNINGS', True)
         self._highlight = highlight
 
-    def __call__(self, *args: 'Any', file_: 'Any' = None, flush_: bool = True, **kwargs: 'Any') -> 'Any':
-        d_out = self._process(args, kwargs)
+    def __call__(
+        self,
+        *args: 'Any',
+        file_: 'Any' = None,
+        flush_: bool = True,
+        frame_depth_: int = 2,
+        **kwargs: 'Any',
+    ) -> 'Any':
+        d_out = self._process(args, kwargs, frame_depth_)
         s = d_out.str(use_highlight(self._highlight, file_))
         print(s, file=file_, flush=flush_)
         if kwargs:
@@ -123,8 +130,8 @@ def __call__(self, *args: 'Any', file_: 'Any' = None, flush_: bool = True, **kwa
         else:
             return args
 
-    def format(self, *args: 'Any', **kwargs: 'Any') -> DebugOutput:
-        return self._process(args, kwargs)
+    def format(self, *args: 'Any', frame_depth_: int = 2, **kwargs: 'Any') -> DebugOutput:
+        return self._process(args, kwargs, frame_depth_)
 
     def breakpoint(self) -> None:
         import pdb
@@ -134,13 +141,13 @@ def breakpoint(self) -> None:
     def timer(self, name: 'Optional[str]' = None, *, verbose: bool = True, file: 'Any' = None, dp: int = 3) -> Timer:
         return Timer(name=name, verbose=verbose, file=file, dp=dp)
 
-    def _process(self, args: 'Any', kwargs: 'Any') -> DebugOutput:
+    def _process(self, args: 'Any', kwargs: 'Any', frame_depth: int) -> DebugOutput:
         """
-        BEWARE: this must be called from a function exactly 2 levels below the top of the stack.
+        BEWARE: this must be called from a function exactly `frame_depth` levels below the top of the stack.
         """
         # HELP: any errors other than ValueError from _getframe? If so please submit an issue
         try:
-            call_frame: 'FrameType' = sys._getframe(2)
+            call_frame: 'FrameType' = sys._getframe(frame_depth)
         except ValueError:
             # "If [ValueError] is deeper than the call stack, ValueError is raised"
             return self.output_class(

devtools/version.py

@@ -1 +1 @@
-VERSION = '0.12.1'
+VERSION = '0.12.2'