Improve exception raising when it comes from an exception handler.

src/tscut/coarse.py

@@ -20,8 +20,8 @@ def do_coarse_processing(ffmpeg_path:str, ffprobe_path:str, mkvmerge_path:str,
 
     try:
         internal_mkv = open(internal_mkv_name, 'wb+')
-    except OSError:
+    except OSError as e:
-        raise TemporaryFileError(f"Impossible to create {internal_mkv_name}")
+        raise TemporaryFileError(f"Impossible to create {internal_mkv_name}") from e
 
     # Extract internal part of MKV
     extract_mkv_part(mkvmerge_path=mkvmerge_path, input_file=input_file, output_file=internal_mkv,

src/tscut/cutting.py

@@ -210,23 +210,24 @@ def cut_recording(media: PreparedMedia, options: ProcessingOptions,
 
         try:
             internal_mkv = open(internal_mkv_name, 'wb+')
-        except OSError:
+        except OSError as e:
-            raise TemporaryFileError(f"Impossible to create file: {internal_mkv_name}")
+            raise TemporaryFileError(f"Impossible to create file: {internal_mkv_name}") from e
 
         try:
             internal_novideo_mkv = open(internal_novideo_mkv_name, 'wb+')
-        except OSError:
+        except OSError as e:
-            raise TemporaryFileError(f"Impossible to create file: {internal_novideo_mkv_name}")
+            raise TemporaryFileError(f"Impossible to create file: \
+                {internal_novideo_mkv_name}") from e
 
         try:
             internal_h264 = open(internal_h264_name, 'wb+')
-        except OSError:
+        except OSError as e:
-            raise TemporaryFileError(f"Impossible to create file: {internal_h264_name}")
+            raise TemporaryFileError(f"Impossible to create file: {internal_h264_name}") from e
 
         try:
             internal_h264_ts = open(internal_h264_ts_name, 'w+', encoding='utf8')
-        except OSError:
+        except OSError as e:
-            raise TemporaryFileError(f"Impossible to create file: {internal_h264_ts_name}")
+            raise TemporaryFileError(f"Impossible to create file: {internal_h264_ts_name}") from e
 
         # logger.info('Merge header, middle and trailer subpart into: %s' % internal_mkv_name)
         # Extract internal part of MKV
@@ -297,8 +298,8 @@ def cut_recording(media: PreparedMedia, options: ProcessingOptions,
     if nb_mkv_parts > 0:
         try:
             full_h264 = open(f'{media.basename}-full.h264', 'wb+')
-        except OSError:
+        except OSError as e:
-            raise TemporaryFileError("Impossible to create file full H264 stream.")
+            raise TemporaryFileError("Impossible to create file full H264 stream.") from e
 
         logger.info('Merging all H264 tracks')
         concatenate_h264_parts(h264parts=h264parts, output=full_h264)
@@ -306,8 +307,9 @@ def cut_recording(media: PreparedMedia, options: ProcessingOptions,
 
         try:
             full_h264_ts = open(f'{media.basename}-ts.txt', 'w+', encoding='utf8')
-        except OSError:
+        except OSError as e:
-            raise TemporaryFileError("Impossible to create file containing all video timestamps.")
+            raise TemporaryFileError("Impossible to create file containing all video timestamps.")\
+            from e
 
         logger.info('Merging H264 timestamps')
         concatenate_h264_ts_parts(h264_ts_parts=h264_ts, output=full_h264_ts)
@@ -329,8 +331,8 @@ def cut_recording(media: PreparedMedia, options: ProcessingOptions,
     if nb_mkv_parts >=1 :
         try:
             final_novideo = open(final_novideo_name, 'rb')
-        except OSError:
+        except OSError as e:
-            raise TemporaryFileError(f"Impossible to open file: {final_novideo_name}")
+            raise TemporaryFileError(f"Impossible to open file: {final_novideo_name}") from e
 
         temporaries.add(final_novideo)
 

src/tscut/pipeline.py

@@ -51,8 +51,8 @@ def process_recording(options: ProcessingOptions, temporaries: TemporaryFiles) -
     try:
         input_file = open(options.input_file, mode='rb')
         logger.debug("Type of input file: %s", type(input_file))
-    except OSError:
+    except OSError as e:
-        raise InvalidMediaError(f"Impossible to open {options.input_file}")
+        raise InvalidMediaError(f"Impossible to open {options.input_file}") from e
 
     format_of_file = get_format(options.tools_paths['ffprobe'], input_file)
 
@@ -90,23 +90,23 @@ def process_recording(options: ProcessingOptions, temporaries: TemporaryFiles) -
                 logger.info("Converting MP4 to MKV.")
                 try:
                     mkv = open(mkvfilename, 'wb+')
-                except OSError:
+                except OSError as e:
-                    raise TemporaryFileError(f"Impossible to create: {mkvfilename}")
+                    raise TemporaryFileError(f"Impossible to create: {mkvfilename}") from e
 
                 ffmpeg_convert(options.tools_paths['ffmpeg'], options.tools_paths['ffprobe'],
                                mp4, 'mp4', mkv, 'matroska', duration)
                 if nb_parts > 0:
                     temporaries.add(mkv)
-        except OSError:
+        except OSError as e:
-            raise TemporaryFileError(f"Impossible to create: {mp4filename}")
+            raise TemporaryFileError(f"Impossible to create: {mp4filename}") from e
 
 
     elif final_format_of_file == SupportedFormat.MP4:
         logger.info("Converting MP4 to MKV")
         try:
             mkv = open(mkvfilename, 'wb+')
-        except OSError:
+        except OSError as e:
-            raise TemporaryFileError(f"Impossible to create: {mkvfilename}")
+            raise TemporaryFileError(f"Impossible to create: {mkvfilename}") from e
         ffmpeg_convert(options.tools_paths['ffmpeg'], options.tools_paths['ffprobe'],
                        input_file, 'mp4', mkv, 'matroska', duration)
         if nb_parts > 0:
@@ -229,12 +229,12 @@ def process_recording(options: ProcessingOptions, temporaries: TemporaryFiles) -
                 for idx_name, sub_name, _, _ in list_of_subtitles:
                     try:
                         idx = open(idx_name,'rb')
-                    except OSError:
+                    except OSError as e:
-                        raise TemporaryFileError(f"Impossible to open {idx_name}")
+                        raise TemporaryFileError(f"Impossible to open {idx_name}") from e
                     try:
                         sub = open(sub_name,'rb')
-                    except OSError:
+                    except OSError as e:
-                        raise TemporaryFileError(f"Impossible to open {sub_name}")
+                        raise TemporaryFileError(f"Impossible to open {sub_name}") from e
 
                     temporaries.add(idx)
                     temporaries.add(sub)