emoji: repair one-shot candidate selection

map/mkemoji

@@ -7,6 +7,7 @@ from pathlib import Path
 
 
 SOURCE = Path(__file__).with_name("emoji.src")
+MAXRUNES = 64
 
 
 def fold(s):
@@ -14,22 +15,30 @@ def fold(s):
     return unicodedata.normalize("NFC", s)
 
 
+def hascontrol(s):
+    return any(unicodedata.category(c) == "Cc" for c in s)
+
+
 def read(path):
     entries = []
     with path.open(encoding="utf-8") as src:
         for lineno, raw in enumerate(src, 1):
             line = raw.rstrip("\r\n")
-            if not line.strip() or line.lstrip().startswith("#"):
+            if not line.strip():
+                continue
+            if "\t" not in line and line.lstrip().startswith("#"):
                 continue
             fields = line.split("\t")
             if len(fields) < 2:
                 raise ValueError(f"{path}:{lineno}: need a result and an alias")
             result = unicodedata.normalize("NFC", fields[0])
-            if not result or any(c.isspace() for c in result):
+            if (not result or len(result) > MAXRUNES or hascontrol(result)
+                    or any(c.isspace() for c in result)):
                 raise ValueError(f"{path}:{lineno}: bad result")
             for field in fields[1:]:
                 alias = fold(field)
-                if not alias or alias != alias.strip():
+                if (not alias or len(alias) > MAXRUNES or hascontrol(alias)
+                        or alias != alias.strip()):
                     raise ValueError(f"{path}:{lineno}: bad alias")
                 entries.append((result, alias))
     return entries