fix: append space at the end of completions (#4611)

tests/xontribs/test_fish_completer.py

@@ -0,0 +1,27 @@
+import pytest
+
+
+@pytest.fixture
+def fish_completer(tmpdir, xession, load_xontrib, fake_process):
+    """vox Alias function"""
+    load_xontrib("fish_completer")
+    xession.env.update(
+        dict(
+            XONSH_DATA_DIR=str(tmpdir),
+            XONSH_SHOW_TRACEBACK=True,
+        )
+    )
+
+    fake_process.register_subprocess(
+        command=["fish", fake_process.any()],
+        # completion for "git chec"
+        stdout=b"""\
+cherry-pick	Apply the change introduced by an existing commit
+checkout	Checkout and switch to a branch""",
+    )
+
+    return fake_process
+
+
+def test_fish_completer(fish_completer, check_completer):
+    assert check_completer("git", prefix="chec") == {"checkout", "cherry-pick"}

xonsh/parsers/completion_context.py

@@ -81,6 +81,27 @@ class CommandContext(NamedTuple):
         else:
             return f"{self.opening_quote}{self.prefix}"
 
+    @property
+    def command(self):
+        if self.args:
+            return self.args[0].raw_value
+        return None
+
+    @property
+    def words_before_cursor(self) -> str:
+        """words without current prefix"""
+        return " ".join([arg.raw_value for arg in self.args[: self.arg_index]])
+
+    @property
+    def text_before_cursor(self) -> str:
+        """full text before cursor including prefix"""
+        return self.words_before_cursor + " " + self.prefix
+
+    @property
+    def begidx(self) -> int:
+        """cursor's position"""
+        return len(self.text_before_cursor)
+
 
 class PythonContext(NamedTuple):
     """

xontrib/fish_completer.py

@@ -1,43 +1,56 @@
 from xonsh.completers import completer
-from xonsh.completers.tools import (
+from xonsh.completers.tools import RichCompletion, contextual_command_completer
-    RichCompletion,
+import os
-    contextual_command_completer,
-    get_filter_function,
-)
-
 import subprocess as sp
 from xonsh.built_ins import XSH
 from xonsh.parsers.completion_context import CommandContext
 
 
-def create_rich_completion(line: str):
+def create_rich_completion(line: str, append_space=False):
     line = line.strip()
     if "\t" in line:
         cmd, desc = map(str.strip, line.split("\t", maxsplit=1))
     else:
         cmd, desc = line, ""
+
+    # special treatment for path completions.
+    # not appending space even if it is a single candidate.
+    if cmd.endswith(os.pathsep):
+        append_space = False
+
     return RichCompletion(
-        str(cmd),
+        cmd,
-        description=str(desc),
+        description=desc,
-        append_space=True,
+        append_space=append_space,
     )
 
 
 @contextual_command_completer
 def fish_proc_completer(ctx: CommandContext):
     """Populate completions using fish shell and remove bash-completer"""
-    args = [arg.value for arg in ctx.args] + [ctx.prefix]
+    if not ctx.args:
-    line = " ".join(args)
+        return
-    args = ["fish", "-c", f"complete -C '{line}'"]
+    line = ctx.text_before_cursor
+
+    script_lines = [
+        f"complete --no-files {ctx.command}",  # switch off basic file completions for the executable
+        f"complete -C '{line}'",
+    ]
+    args = ["fish", "-c", "; ".join(script_lines)]
     env = XSH.env.detype()
-    output = sp.check_output(args, env=env).decode()
+    try:
-    filter_func = get_filter_function()
+        output = sp.check_output(args, env=env).decode()
+    except Exception as ex:
+        print(f"Failed to get fish-completions: {ex}")
+        return
 
     if output:
-        for line in output.strip().splitlines(keepends=False):
+        lines = output.strip().splitlines(keepends=False)
-            comp = create_rich_completion(line)
+        # if there is a single completion candidate then maybe it is over
-            if filter_func(comp, ctx.prefix):
+        append_space = len(lines) == 1
-                yield comp
+        for line in lines:
+            comp = create_rich_completion(line, append_space)
+            yield comp
 
 
 completer.add_one_completer("fish", fish_proc_completer, "<bash")