Next incremental batch of pathlib changes (Issue #210)

This one is related to the previous commit in the sense that the changes are related to file access. It's not really specific to pathlib, however.

The biggest change is to remove most of the exception handling for file access from IV_Swinger2.py (and IV_Swinger_plotter.py.) Most such exceptions would just print and log an error message. But for anyone running the GUI, that wouldn't be very noticeable. Instead, it's better to just let the exceptions propagate up to the GUI and either handle them explicitly there, or let the catch-all exception handler generate the message with the exception text.

In IV_Swinger2_gui.py, the exceptions that are explicitly caught look for either PermissionError if that is specifically what is being checked for, or OSError, which is more general. IOError was merged into OSError in Python 3.3.

python3/IV_Swinger2.py

@@ -1307,15 +1307,9 @@ def save(self, copy_dir=None):
             self.ivs2.logger.print_and_log(dbg_str)
             self.cfg_dump()
         # Attempt to open the file for writing
-        try:
-            with self.cfg_filename.open("w", encoding="utf-8") as cfg_fp:
-                # Write config to file
-                self.cfg.write(cfg_fp)
-        except IOError:
-            # Failed to open file for writing
-            err_str = "Couldn't open config file for writing"
-            self.ivs2.logger.print_and_log(err_str)
-            return
+        with self.cfg_filename.open("w", encoding="utf-8") as cfg_fp:
+            # Write config to file
+            self.cfg.write(cfg_fp)
 
         # Write meter debug values to log file since they may have
         # changed
@@ -1336,13 +1330,8 @@ def save_snapshot(self):
                        f"config to {self.cfg_filename}")
             self.ivs2.logger.print_and_log(dbg_str)
         # Attempt to open the file for writing
-        try:
-            with self.cfg_filename.open("w", encoding="utf-8") as cfg_fp:
-                self.cfg_snapshot.write(cfg_fp)
-        except IOError:
-            # Failed to open file for writing
-            err_str = "Couldn't open config file for writing"
-            self.ivs2.logger.print_and_log(err_str)
+        with self.cfg_filename.open("w", encoding="utf-8") as cfg_fp:
+            self.cfg_snapshot.write(cfg_fp)
 
     # -------------------------------------------------------------------------
     def copy_file(self, dest_dir):
@@ -1356,11 +1345,7 @@ def copy_file(self, dest_dir):
             dbg_str = (f"copy_file: Copying config from "
                        f"{self.cfg_filename} to {dest_dir}")
             self.ivs2.logger.print_and_log(dbg_str)
-        try:
-            shutil.copy(self.cfg_filename, dest_dir)
-        except shutil.Error as e:
-            err_str = f"Couldn't copy config file to {dest_dir} ({e})"
-            self.ivs2.logger.print_and_log(err_str)
+        shutil.copy(self.cfg_filename, dest_dir)
 
     # -------------------------------------------------------------------------
     def populate(self):
@@ -1937,11 +1922,7 @@ def add_sensor_info_to_curve_names(self):
         for csv_dir in self.csv_dirs:
             run_info_filename = get_run_info_filename(Path(csv_dir))
             info_added = False
-            try:
-                (irrad,
-                 temps_dict) = get_sensor_values_from_file(run_info_filename)
-            except (IOError, OSError) as e:
-                self.logger.print_and_log(f"({e})")
+            (irrad, temps_dict) = get_sensor_values_from_file(run_info_filename)
             if self.plot_ref and curve_num == 0:
                 irrad = None
                 temps_dict = {}
@@ -3733,10 +3714,7 @@ def create_run_info_file(self):
             if self._ds18b20_rom_codes:
                 for msg in self._ds18b20_rom_codes:
                     run_info += f"{msg}"
-            try:
-                self.run_info_filename.write_text(run_info, encoding="utf-8")
-            except (IOError, OSError) as e:
-                self.logger.print_and_log(f"({e})")
+            self.run_info_filename.write_text(run_info, encoding="utf-8")
 
     # -------------------------------------------------------------------------
     def convert_sensor_to_run_info_file(self):
@@ -3747,15 +3725,12 @@ def convert_sensor_to_run_info_file(self):
             #    - append the contents of the sensor_info file
             #    - remove the sensor_info file
             self.create_run_info_file()
-            try:
-                with self.sensor_info_filename.open(encoding="utf-8") as f:
-                    sensor_lines = f.read().splitlines()
-                with self.run_info_filename.open("a", encoding="utf-8") as f:
-                    for line in sensor_lines:
-                        f.write(f"{line}\n")
-                Path(self.sensor_info_filename).unlink()
-            except (IOError, OSError) as e:
-                self.logger.print_and_log(f"({e})")
+            with self.sensor_info_filename.open(encoding="utf-8") as f:
+                sensor_lines = f.read().splitlines()
+            with self.run_info_filename.open("a", encoding="utf-8") as f:
+                for line in sensor_lines:
+                    f.write(f"{line}\n")
+            Path(self.sensor_info_filename).unlink()
 
     # -------------------------------------------------------------------------
     def write_sensor_info_to_file(self, msg):
@@ -3767,11 +3742,8 @@ def write_sensor_info_to_file(self, msg):
             info_str = self.translate_ads1115_msg_to_irradiance(msg)
         else:
             info_str = msg
-        try:
-            with self.run_info_filename.open("a", encoding="utf-8") as f:
-                f.write(f"{info_str}")
-        except (IOError, OSError) as e:
-            self.logger.print_and_log(f"({e})")
+        with self.run_info_filename.open("a", encoding="utf-8") as f:
+            f.write(f"{info_str}")
 
     # -------------------------------------------------------------------------
     def translate_ads1115_msg_to_photodiode_temp_scaling(self, msg):
@@ -3911,33 +3883,30 @@ def update_irradiance(self, new_irradiance):
         new_lines = []
         irrad_re = re.compile(r"Irradiance: (\d+) W/m\^2")
         ext_irrad_re = re.compile(r"(\d+) @ (\S+) deg C")
-        try:
-            with self.run_info_filename.open(encoding="utf-8") as f:
-                for line in f.read().splitlines():
-                    match = irrad_re.search(line)
-                    if match:
-                        ext_match = ext_irrad_re.search(line)
-                        if ext_match:
-                            old_irradiance = int(match.group(1))
-                            ratio = new_irradiance / old_irradiance
-                            old_uncomp_irrad = int(ext_match.group(1))
-                            temp = float(ext_match.group(2))
-                            new_uncomp_irrad = int(round(old_uncomp_irrad *
-                                                         ratio))
-                            ext_str = f" ({new_uncomp_irrad} @ {temp} deg C)"
-                        else:
-                            ext_str = ""
-                        round_new_irradiance = int(round(new_irradiance))
-                        new_lines.append(f"Irradiance: {round_new_irradiance} "
-                                         f"W/m^2{ext_str}")
-                        self.irradiance = round_new_irradiance
+        with self.run_info_filename.open(encoding="utf-8") as f:
+            for line in f.read().splitlines():
+                match = irrad_re.search(line)
+                if match:
+                    ext_match = ext_irrad_re.search(line)
+                    if ext_match:
+                        old_irradiance = int(match.group(1))
+                        ratio = new_irradiance / old_irradiance
+                        old_uncomp_irrad = int(ext_match.group(1))
+                        temp = float(ext_match.group(2))
+                        new_uncomp_irrad = int(round(old_uncomp_irrad *
+                                                     ratio))
+                        ext_str = f" ({new_uncomp_irrad} @ {temp} deg C)"
                     else:
-                        new_lines.append(line)
-            with self.run_info_filename.open("w", encoding="utf-8") as f:
-                for line in new_lines:
-                    f.write(f"{line}\n")
-        except (IOError, OSError) as e:
-            self.logger.print_and_log(f"({e})")
+                        ext_str = ""
+                    round_new_irradiance = int(round(new_irradiance))
+                    new_lines.append(f"Irradiance: {round_new_irradiance} "
+                                     f"W/m^2{ext_str}")
+                    self.irradiance = round_new_irradiance
+                else:
+                    new_lines.append(line)
+        with self.run_info_filename.open("w", encoding="utf-8") as f:
+            for line in new_lines:
+                f.write(f"{line}\n")
 
     # -------------------------------------------------------------------------
     def log_msg_from_arduino(self, msg):
@@ -4961,11 +4930,7 @@ def copy_file_to_parent(self, filename):
            output directory)
         """
         run_dir = self.hdd_output_dir.parent
-        try:
-            shutil.copy(filename, run_dir)
-        except shutil.Error as e:
-            err_str = f"Couldn't copy {filename} to {run_dir} ({e})"
-            self.logger.print_and_log(err_str)
+        shutil.copy(filename, run_dir)
 
     # -------------------------------------------------------------------------
     def write_adc_pairs_to_csv_file(self, filename, adc_pairs):
@@ -4988,11 +4953,7 @@ def read_adc_pairs_from_csv_file(self, filename):
            of ADC pairs
         """
         adc_pairs = []
-        try:
-            csv_lines = filename.read_text(encoding="utf-8").splitlines()
-        except IOError:
-            self.logger.print_and_log(f"ERROR: Cannot read {filename}")
-            return []
+        csv_lines = filename.read_text(encoding="utf-8").splitlines()
         for ii, line in enumerate(csv_lines):
             if ii == 0:
                 expected_first_line = "CH0 (voltage), CH1 (current)"

python3/IV_Swinger2_gui.py

@@ -273,7 +273,8 @@ def handle_early_exception():
     if not getattr(sys, "frozen", False):
         print(err_msg)
         return
-    tmp_file = Path(tempfile.NamedTemporaryFile(delete=False).name)
+    with tempfile.NamedTemporaryFile(delete=False) as f:
+        tmp_file = Path(f.name)
     err_msg += f"""
 -----------------------------------------------------------
 Please copy/paste the above and send it to csatt1@gmail.com
@@ -332,9 +333,10 @@ def retry_if_pdf_permission_denied(func, *args):
        file if they have it open in a viewer. Then the function is
        called again.
     """
+    rc = RC_FAILURE
     try:
         rc = func(*args)
-    except IOError as e:
+    except PermissionError as e:
         if pdf_permission_denied(e):
             err_str = (f"({e})\n\nPDF could not be written. If you have it "
                        f"open in a viewer, close it BEFORE clicking OK.")
@@ -347,6 +349,8 @@ def retry_if_pdf_permission_denied(func, *args):
                     err_str = (f"({ee})\n\nPDF still could not be written. "
                                f"It will not be updated.")
                     tkmsg.showerror(message=err_str)
+        else:
+            tkmsg.showerror(message=e)
     return rc
 
 
@@ -817,18 +821,17 @@ def check_app_data_dir(self, app_data_dir):
         """
         try:
             app_data_dir.mkdir(exist_ok=True)
-        except (IOError, OSError):
+        except PermissionError:
             err_msg = f"""
 FATAL ERROR: This user does not have
 permission to create directories (folders) in
 {app_data_dir.parent}"""
             tkmsg.showerror(message=err_msg)
             sys.exit()
         try:
-            dummy_file = app_data_dir / "DUMMY_FILE"
-            dummy_file.touch()
-            dummy_file.unlink()
-        except (IOError, OSError):
+            (app_data_dir / "DUMMY_FILE").touch()
+            (app_data_dir / "DUMMY_FILE").unlink()
+        except PermissionError:
             err_msg = f"""
 FATAL ERROR: This user does not have
 permission to create files in
@@ -876,7 +879,7 @@ def get_version(self):
         version_file = self.app_dir / VERSION_FILE
         try:
             lines = version_file.read_text(encoding="utf-8").splitlines()
-        except IOError:
+        except OSError:
             err_str = f"ERROR: {version_file} cannot be read"
             self.ivs2.logger.print_and_log(err_str)
             return
@@ -1582,7 +1585,7 @@ def restore_config(self, run_dir, config_dir,
         if (run_dir is not None and run_dir.resolve() != config_dir.resolve()
                 and cfg_file.exists()):
             self.config.cfg_filename = original_cfg_file
-            self.config.save_snapshot()
+            self.save_snapshot()
 
     # -------------------------------------------------------------------------
     def handle_plot_power_or_ref_event(self, button="power", plot=True):
@@ -1936,7 +1939,19 @@ def save_config(self):
                 (not self.looping or self.loop_save_results)):
             copy_dir = self.ivs2.hdd_output_dir
 
-        self.config.save(copy_dir=copy_dir)
+        try:
+            self.config.save(copy_dir=copy_dir)
+        except OSError as e:
+            tkmsg.showerror(message=e)
+
+    # -------------------------------------------------------------------------
+    def save_snapshot(self):
+        """Wrapper around save_snapshot() method of the Configuration class.
+        """
+        try:
+            self.config.save_snapshot()
+        except OSError as e:
+            tkmsg.showerror(message=e)
 
     # -------------------------------------------------------------------------
     def show_preferences(self, event=None):
@@ -3721,7 +3736,7 @@ def copy_dirs(self, src_dirs, overwrite):
                 if overwrite:
                     try:
                         shutil.rmtree(dest_dir)
-                    except (IOError, OSError, shutil.Error) as e:
+                    except (OSError, shutil.Error) as e:
                         err_str = f"ERROR: removing {dest_dir} ({e})"
                         tkmsg.showerror(message=err_str)
                         continue
@@ -3734,7 +3749,7 @@ def copy_dirs(self, src_dirs, overwrite):
                 else:
                     num_copied["runs"] += 1
                 self.master.ivs2.logger.log(f"Copied {src_dir} to {dest_dir}")
-            except (IOError, OSError, shutil.Error) as e:
+            except (OSError, shutil.Error) as e:
                 err_str = (f"ERROR: error copying {src_dir} to "
                            f"{dest_dir}\n({e})")
                 tkmsg.showerror(message=err_str)
@@ -7214,7 +7229,7 @@ def revert(self):
            values to properties and the config
         """
         # Restore config
-        self.master.config.save_snapshot()
+        self.master.save_snapshot()
         self.master.config.get()
 
         # Restore properties
@@ -9739,7 +9754,7 @@ def revert(self):
            values to properties and the config
         """
         # Restore config
-        self.master.config.save_snapshot()
+        self.master.save_snapshot()
         self.master.config.get()
 
         # Restore properties

python3/IV_Swinger2_sim.py

@@ -92,7 +92,6 @@
 # standalone. The main() function creates a SimulatorDialog object with a
 # basic ttk.Frame object as its parent and runs it.
 #
-from pathlib import Path
 import re
 from tkinter import ttk
 import tkinter as tk

python3/IV_Swinger_plotter.py

@@ -350,12 +350,7 @@ def data_points(self):
         """
         csv = self.csv_filename
         if not self._data_points:
-            try:
-                csv_lines = csv.read_text(encoding="utf-8").splitlines()
-            except IOError:
-                PrintAndOrLog.print_and_log_msg(self.logger,
-                                                f"Cannot read {csv}")
-                return []
+            csv_lines = csv.read_text(encoding="utf-8").splitlines()
             for ii, line in enumerate(csv_lines):
                 if ii == 0:
                     expected_first_line = "Volts, Amps, Watts, Ohms"