Revert "cu2qu.errors: remove unused exceptions"

This reverts commit 2e51226dedc6a03f3de8a70220e52d0026cc0d95.

Lib/fontTools/cu2qu/errors.py

@@ -21,3 +21,56 @@ class ApproxNotFoundError(Error):
         message = "no approximation found: %s" % curve
         super(Error, self).__init__(message)
         self.curve = curve
+
+
+class UnequalZipLengthsError(Error):
+    pass
+
+
+class IncompatibleGlyphsError(Error):
+    def __init__(self, glyphs):
+        assert len(glyphs) > 1
+        self.glyphs = glyphs
+        names = set(repr(g.name) for g in glyphs)
+        if len(names) > 1:
+            self.combined_name = "{%s}" % ", ".join(sorted(names))
+        else:
+            self.combined_name = names.pop()
+
+    def __repr__(self):
+        return "<%s %s>" % (type(self).__name__, self.combined_name)
+
+
+class IncompatibleSegmentNumberError(IncompatibleGlyphsError):
+    def __str__(self):
+        return "Glyphs named %s have different number of segments" % (
+            self.combined_name
+        )
+
+
+class IncompatibleSegmentTypesError(IncompatibleGlyphsError):
+    def __init__(self, glyphs, segments):
+        IncompatibleGlyphsError.__init__(self, glyphs)
+        self.segments = segments
+
+    def __str__(self):
+        lines = []
+        ndigits = len(str(max(self.segments)))
+        for i, tags in sorted(self.segments.items()):
+            lines.append(
+                "%s: (%s)" % (str(i).rjust(ndigits), ", ".join(repr(t) for t in tags))
+            )
+        return "Glyphs named %s have incompatible segment types:\n  %s" % (
+            self.combined_name,
+            "\n  ".join(lines),
+        )
+
+
+class IncompatibleFontsError(Error):
+    def __init__(self, glyph_errors):
+        self.glyph_errors = glyph_errors
+
+    def __str__(self):
+        return "fonts contains incompatible glyphs: %s" % (
+            ", ".join(repr(g) for g in sorted(self.glyph_errors.keys()))
+        )