Fixing bash completion bug when prefix started with '>', '<', or ':' (#4826)

* Fixing bash completion bug when prefix started with '>', '<', or ':'

* Fixing code formatting

* More code formatting fixes

* Fixing test

* Refactor to fix bug by improving completion parser

* Supporting '<' and '>>' in completion parser

* Support for all IO redirect tokens

news/fix-bash-completion.rst

@@ -0,0 +1,24 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* Fixed a bash completion bug when prefixing a file path with '<' or '>' (for redirecting stdin/stdout/stderr)
+* Fixed a bash completion bug when completing a git branch name when deleting a remote branch (e.g. `git push origin :dev-branch`)
+
+**Security:**
+
+* <news item>

tests/completers/test_bash_completer.py

@@ -232,3 +232,38 @@ def test_equal_sign_arg(command_context, completions, lprefix, exp_append_space)
         isinstance(comp, RichCompletion) and comp.append_space == exp_append_space
         for comp in bash_completions
     )
+
+
+@pytest.fixture
+def bash_completer(fake_process):
+    fake_process.register_subprocess(
+        command=["bash", fake_process.any()],
+        # completion for "git push origin :dev-b"
+        stdout=b"""\
+complete -o bashdefault -o default -o nospace -F __git_wrap__git_main git
+dev-branch
+""",
+    )
+
+    return fake_process
+
+
+# git push origin :dev-b<TAB>  ->  git push origin :dev-branch
+def test_git_delete_remote_branch(bash_completer):
+    command_context = CommandContext(
+        args=(
+            CommandArg("git"),
+            CommandArg("push"),
+            CommandArg("origin"),
+        ),
+        arg_index=3,
+        prefix=":dev-b",
+    )
+    bash_completions, bash_lprefix = complete_from_bash(
+        CompletionContext(command_context)
+    )
+    assert bash_completions == {"dev-branch"} and bash_lprefix == 5
+    assert all(
+        isinstance(comp, RichCompletion) and comp.append_space is False
+        for comp in bash_completions
+    )

tests/test_completion_context.py

@@ -127,6 +127,38 @@ COMMAND_EXAMPLES = (
             suffix="b",
         ),
     ),
+    (
+        f"command >/dev/nul{X}",
+        CommandContext(
+            args=(CommandArg("command"), CommandArg(">", is_io_redir=True)),
+            arg_index=2,
+            prefix="/dev/nul",
+        ),
+    ),
+    (
+        f"command 2>/dev/nul{X}",
+        CommandContext(
+            args=(CommandArg("command"), CommandArg("2>", is_io_redir=True)),
+            arg_index=2,
+            prefix="/dev/nul",
+        ),
+    ),
+    (
+        f"command >>/dev/nul{X}",
+        CommandContext(
+            args=(CommandArg("command"), CommandArg(">>", is_io_redir=True)),
+            arg_index=2,
+            prefix="/dev/nul",
+        ),
+    ),
+    (
+        f"command </dev/nul{X}",
+        CommandContext(
+            args=(CommandArg("command"), CommandArg("<", is_io_redir=True)),
+            arg_index=2,
+            prefix="/dev/nul",
+        ),
+    ),
 )
 
 EMPTY_COMMAND_EXAMPLES = (

xonsh/completers/bash_completion.py

@@ -432,6 +432,10 @@ def bash_completions(
     # to be incorrectly calculated, so it needs to be fixed here
     if "=" in prefix and "=" not in commprefix:
         strip_len = prefix.index("=") + 1
+    # Fix case where remote git branch is being deleted
+    # (e.g. 'git push origin :dev-branch')
+    elif ":" in prefix and ":" not in commprefix:
+        strip_len = prefix.index(":") + 1
 
     return out, max(len(prefix) - strip_len, 0)
 

xonsh/parsers/completion_context.py

@@ -35,6 +35,8 @@ class CommandArg(NamedTuple):
     """The arg's opening quote (if it exists)"""
     closing_quote: str = ""
     """The arg's closing quote (if it exists)"""
+    is_io_redir: bool = False
+    """Whether the arg is IO redirection"""
 
     @property
     def raw_value(self):
@@ -328,6 +330,13 @@ class CompletionContextParser:
         "OR",
     }
     used_tokens |= multi_tokens
+    io_redir_tokens = {
+        "LT",
+        "GT",
+        "RSHIFT",
+        "IOREDIRECT",
+    }
+    used_tokens |= io_redir_tokens
     artificial_tokens = {"ANY"}
     ignored_tokens = {"INDENT", "DEDENT", "WS"}
 
@@ -701,7 +710,8 @@ class CompletionContextParser:
 
         arg = CompletionContextParser.try_parse_string_literal(raw_arg)
         if arg is None:
-            arg = CommandArg(raw_arg)
+            is_io_redir = p.slice[1].type in self.io_redir_tokens
+            arg = CommandArg(raw_arg, is_io_redir=is_io_redir)
 
         p[0] = Spanned(arg, span, cursor_context=relative_cursor)
 
@@ -727,7 +737,9 @@ class CompletionContextParser:
         joined_raw = f"{last_arg.value.raw_value}{in_between}{new_arg.value.raw_value}"
         string_literal = self.try_parse_string_literal(joined_raw)
 
-        if string_literal is not None or not in_between:
+        is_redir = new_arg.value.is_io_redir or last_arg.value.is_io_redir
+
+        if string_literal is not None or (not in_between and not is_redir):
             if string_literal is not None:
                 # we're appending to a partial string, e.g. `"a b`
                 arg = string_literal