[songbook] Add option --error

Closes #123

patacrep/build.py

@@ -114,7 +114,12 @@ class Songbook:
         self._config['filename'] = output.name[:-4]
 
         renderer.render_tex(output, self._config)
+
+        # Get all errors, and maybe exit program
         self._errors.extend(renderer.errors)
+        if self.config['_error'] == "failonbook":
+            if self.has_errors():
+                raise errors.SongbookError("Some songs contain errors. Stopping as requested.")
 
     def has_errors(self):
         """Return `True` iff errors have been encountered in the book.

patacrep/content/song.py

@@ -24,6 +24,12 @@ class SongRenderer(ContentItem):
         """Iterate over song errors."""
         yield from self.song.errors
 
+    def has_errors(self):
+        """Return `True` iff errors has been found."""
+        for _ in self.iter_errors():
+            return True
+        return False
+
     def begin_new_block(self, previous, __context):
         """Return a boolean stating if a new block is to be created."""
         return not isinstance(previous, SongRenderer)
@@ -57,7 +63,7 @@ class SongRenderer(ContentItem):
         """Order by song path"""
         return self.song.fullpath < other.song.fullpath
 
-#pylint: disable=unused-argument
+#pylint: disable=unused-argument, too-many-branches
 def parse(keyword, argument, contentlist, config):
     """Parse data associated with keyword 'song'.
 
@@ -107,7 +113,17 @@ def parse(keyword, argument, contentlist, config):
                             ))
                     except ContentError as error:
                         songlist.append_error(error)
+                        if config['_error'] == "failonsong":
+                            raise errors.SongbookError(
+                                "Error in song '{}'. Stopping as requested."
+                                .format(os.path.join(songdir.fullpath, filename))
+                                )
                         continue
+                    if renderer.has_errors() and config['_error'] == "failonsong":
+                        raise errors.SongbookError(
+                            "Error in song '{}'. Stopping as requested."
+                            .format(os.path.join(songdir.fullpath, filename))
+                            )
                     songlist.append(renderer)
                     config["_langs"].add(renderer.song.lang)
             if len(songlist) > before:

patacrep/errors.py

@@ -5,11 +5,6 @@ class SongbookError(Exception):
 
     Songbook errors should inherit from this one.
     """
-    pass
-
-class YAMLError(SongbookError):
-    """Error during songbook file decoding"""
-
     def __init__(self, message=None):
         super().__init__()
         self.message = message
@@ -17,6 +12,11 @@ class YAMLError(SongbookError):
     def __str__(self):
         return self.message
 
+
+class YAMLError(SongbookError):
+    """Error during songbook file decoding"""
+    pass
+
 class TemplateError(SongbookError):
     """Error during template generation"""
 

patacrep/songbook/__main__.py

@@ -86,6 +86,25 @@ def argument_parser(args):
         default=[True],
         )
 
+    parser.add_argument(
+        '--error', '-e', nargs=1,
+        help=textwrap.dedent("""\
+                By default, this program tries hard to fix or ignore song and book errors. This option changes this behaviour:
+                - failonsong: stop as soon as a song contains (at least) one error;
+                - failonbook: stop when all the songs have been parsed and rendered, if any error was met;
+                - fix: tries to fix (or ignore) errors.
+
+                Note that compilation *may* fail even with `--error=fix`.
+        """),
+        type=str,
+        choices=[
+            "failonsong",
+            "failonbook",
+            "fix",
+        ],
+        default=["fix"],
+        )
+
     parser.add_argument(
         '--steps', '-s', nargs=1, type=str,
         action=ParseStepsAction,
@@ -127,6 +146,7 @@ def main(args):
             for datadir in reversed(options.datadir):
                 songbook['datadir'].insert(0, datadir)
         songbook['_cache'] = options.cache[0]
+        songbook['_error'] = options.error[0]
 
         sb_builder = SongbookBuilder(songbook)
         sb_builder.unsafe = True