Fix rendering when prompt_suffix is empty

CHANGES.rst

@@ -11,6 +11,8 @@ Unreleased
     the ``Context.invoke()`` method. :issue:`3066` :issue:`3065` :pr:`3068`
 -   Fix conversion of ``Sentinel.UNSET`` happening too early, which caused incorrect
     behavior for multiple parameters using the same name. :issue:`3071` :pr:`3079`
+-   Fix rendering when ``prompt`` and ``confirm`` parameter ``prompt_suffix`` is
+    empty. :issue:`3019` :pr:`3021`
 
 Version 8.3.0
 --------------

src/click/termui.py

@@ -119,6 +119,13 @@ def prompt(
                          show_choices is true and text is "Group by" then the
                          prompt will be "Group by (day, week): ".
 
+    .. versionchanged:: 8.3.1
+        The prompt displayed no longer strips trailing whitespace, adding a single
+        trailing space. Instead, ``text`` is now displayed followed by
+        ``prompt_suffix`` with no whitespace manipulation.
+        When ``err`` is True the prompt is sent to ``stderr`` except for the last
+        character which is sent to ``stdout``.
+
     .. versionadded:: 8.0
         ``confirmation_prompt`` can be a custom string.
 
@@ -138,10 +145,10 @@ def prompt_func(text: str) -> str:
         try:
             # Write the prompt separately so that we get nice
             # coloring through colorama on Windows
-            echo(text.rstrip(" "), nl=False, err=err)
-            # Echo a space to stdout to work around an issue where
+            echo(text[:-1], nl=False, err=err)
+            # Echo the last character to stdout to work around an issue where
             # readline causes backspace to clear the whole line.
-            return f(" ")
+            return f(text[-1:])
         except (KeyboardInterrupt, EOFError):
             # getpass doesn't print a newline if the user aborts input with ^C.
             # Allegedly this behavior is inherited from getpass(3).
@@ -214,6 +221,13 @@ def confirm(
     :param err: if set to true the file defaults to ``stderr`` instead of
                 ``stdout``, the same as with echo.
 
+    .. versionchanged:: 8.3.1
+        The prompt displayed no longer strips trailing whitespace, adding a single
+        trailing space. Instead, ``text`` is now displayed followed by
+        ``prompt_suffix`` with no whitespace manipulation.
+        When ``err`` is True the prompt is sent to ``stderr`` except for the last
+        character which is sent to ``stdout``.
+
     .. versionchanged:: 8.0
         Repeat until input is given if ``default`` is ``None``.
 
@@ -231,10 +245,10 @@ def confirm(
         try:
             # Write the prompt separately so that we get nice
             # coloring through colorama on Windows
-            echo(prompt.rstrip(" "), nl=False, err=err)
-            # Echo a space to stdout to work around an issue where
+            echo(prompt[:-1], nl=False, err=err)
+            # Echo the last character to stdout to work around an issue where
             # readline causes backspace to clear the whole line.
-            value = visible_prompt_func(" ").lower().strip()
+            value = visible_prompt_func(prompt[-1:]).lower().strip()
         except (KeyboardInterrupt, EOFError):
             raise Abort() from None
         if value in ("y", "yes"):

tests/test_utils.py

@@ -481,24 +481,48 @@ def emulate_input(text):
     assert out == "Prompt to stdin: "
     assert err == ""
 
+    emulate_input("asdlkj\n")
+    click.prompt("Prompt to stdin with no suffix", prompt_suffix="")
+    out, err = capfd.readouterr()
+    assert out == "Prompt to stdin with no suffix"
+    assert err == ""
+
     emulate_input("asdlkj\n")
     click.prompt("Prompt to stderr", err=True)
     out, err = capfd.readouterr()
     assert out == " "
     assert err == "Prompt to stderr:"
 
+    emulate_input("asdlkj\n")
+    click.prompt("Prompt to stderr with no suffix", prompt_suffix="", err=True)
+    out, err = capfd.readouterr()
+    assert out == "x"
+    assert err == "Prompt to stderr with no suffi"
+
     emulate_input("y\n")
     click.confirm("Prompt to stdin")
     out, err = capfd.readouterr()
     assert out == "Prompt to stdin [y/N]: "
     assert err == ""
 
+    emulate_input("y\n")
+    click.confirm("Prompt to stdin with no suffix", prompt_suffix="")
+    out, err = capfd.readouterr()
+    assert out == "Prompt to stdin with no suffix [y/N]"
+    assert err == ""
+
     emulate_input("y\n")
     click.confirm("Prompt to stderr", err=True)
     out, err = capfd.readouterr()
     assert out == " "
     assert err == "Prompt to stderr [y/N]:"
 
+    emulate_input("y\n")
+    click.confirm("Prompt to stderr with no suffix", prompt_suffix="", err=True)
+    out, err = capfd.readouterr()
+    assert out == "]"
+    assert err == "Prompt to stderr with no suffix [y/N"
+
     monkeypatch.setattr(click.termui, "isatty", lambda x: True)
     monkeypatch.setattr(click.termui, "getchar", lambda: " ")