File handling: use context managers for safer resource management

Author: PierreRaybaut

plotpy/builder/shape.py

@@ -179,7 +179,8 @@ def svg(
         assert shape in ("circle", "rectangle", "square")
         assert isinstance(fname_or_data, (str, bytes))
         if isinstance(fname_or_data, str):
-            data = open(fname_or_data, "rb").read()
+            with open(fname_or_data, "rb") as file:
+                data = file.read()
         else:
             data = fname_or_data
         shapeklass = {

plotpy/tests/features/test_loadsaveitems_pickle.py

@@ -192,14 +192,14 @@ class PickleTest(IOTest):
 
     def restore_items(self) -> None:
         """Restore items"""
-        f = open(self.FNAME, "rb")
-        self.plot.restore_items(f)
+        with open(self.FNAME, "rb") as f:
+            self.plot.restore_items(f)
 
     def save_items(self) -> None:
         """Save items"""
         self.plot.select_all()
-        f = open(self.FNAME, "wb")
-        self.plot.save_items(f, selected=True)
+        with open(self.FNAME, "wb") as f:
+            self.plot.save_items(f, selected=True)
 
 
 def test_pickle() -> None:

plotpy/tests/tools/test_get_rectangle_with_svg.py

@@ -29,7 +29,8 @@ class SVGToolExample(RectangularShapeTool):
 
     def create_shape(self):
         """Create shape to be drawn"""
-        svg_data = open(self.SVG_FNAME, "rb").read()
+        with open(self.SVG_FNAME, "rb") as svg_file:
+            svg_data = svg_file.read()
         shape = make.svg("rectangle", svg_data, 0, 0, 1, 1, "SVG")
         self.set_shape_style(shape)
         return shape, 0, 2

plotpy/tools/item.py

@@ -311,8 +311,8 @@ def activate_command(self, plot: BasePlot, checked: bool) -> None:
         )
         if not fname:
             return
-        itemfile = open(fname, "wb")
-        plot.save_items(itemfile, selected=True)
+        with open(fname, "wb") as itemfile:
+            plot.save_items(itemfile, selected=True)
 
 
 class LoadItemsTool(OpenFileTool):
@@ -343,8 +343,8 @@ def activate_command(self, plot: BasePlot, checked: bool) -> None:
         filename = self.get_filename(plot)
         if not filename:
             return
-        itemfile = open(filename, "rb")
-        plot.restore_items(itemfile)
+        with open(filename, "rb") as itemfile:
+            plot.restore_items(itemfile)
         plot.replot()
 
 

plotpy/widgets/qtdesigner.py

@@ -36,7 +36,8 @@ def loadui(fname, replace_class="QwtPlot"):
     QtDesigner plugins because they don't inheritate from a PyQt5.QtGui
     object.
     """
-    uifile_text = open(fname).read().replace(replace_class, "QFrame")
+    with open(fname) as f:
+        uifile_text = f.read().replace(replace_class, "QFrame")
     ui, base_class = uic.loadUiType(io.StringIO(uifile_text))
 
     class Form(base_class, ui):
@@ -55,12 +56,10 @@ def compileui(fname, replace_class="QwtPlot"):
     :param fname:
     :param replace_class:
     """
-    uifile_text = open(fname).read().replace("QwtPlot", "QFrame")
-    uic.compileUi(
-        io.StringIO(uifile_text),
-        open(fname.replace(".ui", "_ui.py"), "w"),
-        pyqt3_wrapper=True,
-    )
+    with open(fname) as f:
+        uifile_text = f.read().replace("QwtPlot", "QFrame")
+    with open(fname.replace(".ui", "_ui.py"), "w") as pyfile:
+        uic.compileUi(io.StringIO(uifile_text), pyfile, pyqt3_wrapper=True)
 
 
 def create_qtdesigner_plugin(