Preserve trailing underscore

README.md

@@ -61,7 +61,7 @@ Reserved URL characters can be included using escape patterns:
 
 For example, <https://api.memegen.link/images/ugandanknuck/~hspecial_characters~q/underscore__-dash--.png> produces:
 
-![Escaped Characters](https://api.memegen.link/images/ugandanknuck/~hspecial_characters~q/underscore___dash--.png?width=800&token=imyyyyk8qex6m2jz8bar)
+![Escaped Characters](https://api.memegen.link/images/ugandanknuck/~hspecial_characters~q/underscore__-dash--.png?width=800&token=imyyyyk8qex6m2jz8bar)
 
 All of the `POST` endpoints will return image URLs with special characters replaced with these alternatives.
 

app/tests/test_utils_text.py

@@ -14,6 +14,7 @@
     (['That\'s not how "this" works'], "That's_not_how_''this''_works"),
     (["git commit --no-verify"], "git_commit_----no--verify"),
     (["_username likes _charname"], "__username_likes___charname"),
+    (["underscore_ dash-"], "underscore__-dash--"),
 ]
 
 

app/utils/text.py

@@ -10,29 +10,7 @@ def encode(lines: list[str]) -> str:
         if line == "/":
             encoded_lines.append("_")
         elif line:
-            encoded = unquote(line)
-            for before, after in [
-                ("_", "__"),
-                ("-", "--"),
-                (" ", "_"),
-                ("?", "~q"),
-                ("%", "~p"),
-                ("#", "~h"),
-                ('"', "''"),
-                ("/", "~s"),
-                ("\\", "~b"),
-                ("\n", "~n"),
-                ("&", "~a"),
-                ("<", "~l"),
-                (">", "~g"),
-                ("‘", "'"),
-                ("’", "'"),
-                ("“", '"'),
-                ("”", '"'),
-                ("–", "-"),
-            ]:
-                encoded = encoded.replace(before, after)
-            encoded_lines.append(encoded)
+            encoded_lines.append(_encode(line))
         else:
             encoded_lines.append("_")
 
@@ -41,6 +19,39 @@ def encode(lines: list[str]) -> str:
     return slug or "_"
 
 
+def _encode(line):
+    has_trailing_under = "_ " in line
+
+    encoded = unquote(line)
+
+    for before, after in [
+        ("_", "__"),
+        ("-", "--"),
+        (" ", "_"),
+        ("?", "~q"),
+        ("%", "~p"),
+        ("#", "~h"),
+        ('"', "''"),
+        ("/", "~s"),
+        ("\\", "~b"),
+        ("\n", "~n"),
+        ("&", "~a"),
+        ("<", "~l"),
+        (">", "~g"),
+        ("‘", "'"),
+        ("’", "'"),
+        ("“", '"'),
+        ("”", '"'),
+        ("–", "-"),
+    ]:
+        encoded = encoded.replace(before, after)
+
+    if has_trailing_under:
+        encoded = encoded.replace("___", "__-")
+
+    return encoded
+
+
 def decode(slug: str) -> list[str]:
     has_dash = "_----" in slug
     has_arrow = "_--~g" in slug