Introduce new resolver for executables to replace commands_cache usages and speed up everything (#5544)

* remove commands_cache from pyghooks to avoid cc.update_cache on every key press

* create executables.py

* replace cc.locate_binary to locate_executable

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* vc: replace locate_binary

* pyghooks: remove commands_cache

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* remove unused func _yield_executables

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Move `executables_in` from tools to commands_cache to avoid circular imports.

* First steps to `procs.executables` that is based on `commands_cache` and `tools`.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* test_executables

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* add not recommended notes

* tests

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Add `get_paths` with test

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Fix source test

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* vc: remove tests because commands cache is not used

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* specs: fix exception for recursive call

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* specs: fix exception for recursive call

* improve test_locate_executable

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* fix test

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* fix test

* beautify pathext

* tests

* docs

* tests

* update locators

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* locate_file

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* comments

* return environ locate bin test

* comments

* Update xonsh/procs/executables.py

Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>

* Update xonsh/procs/executables.py

Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>

* Update xonsh/procs/executables.py

Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* add itertools

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* moving is_executable

* doc

* optimization is_executable_in_windows

* micro improvements

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* news

* news

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* bump test

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: a <1@1.1>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>

news/commands_cache_new_resolve_executable.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* New executable resolving method was introduced and the commands_cache usages were replaced in the key places. As result we expect speed up in xonsh startup, reducing lagging during typing in prompt and speed ups during the commands execution (#5544 by @anki-code).
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* <news item>
+
+**Security:**
+
+* <news item>

tests/aliases/test_source.py

@@ -1,6 +1,7 @@
 import builtins
 import os.path
 from contextlib import contextmanager
+from pathlib import Path
 from unittest.mock import MagicMock
 
 import pytest
@@ -34,9 +35,8 @@ def test_source_current_dir(mockopen, monkeypatch, mocked_execx_checker):
     assert mocked_execx_checker == ["foo", "bar"]
 
 
-def test_source_path(mockopen, mocked_execx_checker, patch_locate_binary, xession):
+def test_source_path(mockopen, mocked_execx_checker, xession):
-    patch_locate_binary(xession.commands_cache)
+    with xession.env.swap(PATH=[Path(__file__).parent.parent / "bin"]):
-
         source_alias(["foo", "bar"])
     path_foo = os.path.join("bin", "foo")
     path_bar = os.path.join("bin", "bar")

tests/bin/bar

@@ -0,0 +1 @@
+# Test source_alias

tests/bin/foo

@@ -0,0 +1 @@
+# Test source_alias

tests/procs/test_executables.py

@@ -0,0 +1,46 @@
+import os
+
+from xonsh.environ import Env
+from xonsh.platform import ON_WINDOWS
+from xonsh.procs.executables import get_paths, get_possible_names, locate_executable
+
+
+def test_get_possible_names():
+    env = Env(PATHEXT=[".EXE", ".COM"])
+    assert get_possible_names("file", env) == ["file", "file.exe", "file.com"]
+    assert get_possible_names("FILE", env) == ["FILE", "FILE.EXE", "FILE.COM"]
+
+
+def test_get_paths(tmpdir):
+    bindir1 = str(tmpdir.mkdir("bindir1"))
+    bindir2 = str(tmpdir.mkdir("bindir2"))
+    env = Env(PATH=[bindir1, bindir2, bindir1, "nodir"])
+    assert get_paths(env) == (bindir2, bindir1)
+
+
+def test_locate_executable(tmpdir, xession):
+    bindir = tmpdir.mkdir("bindir")
+    bindir.mkdir("subdir")
+    executables = ["file1.EXE", "file2.COM", "file2.EXE", "file3"]
+    not_executables = ["file4.EXE", "file5"]
+    for exefile in executables + not_executables:
+        f = bindir / exefile
+        f.write_text("binary", encoding="utf8")
+        if exefile in executables:
+            os.chmod(f, 0o777)
+
+    pathext = [".EXE", ".COM"] if ON_WINDOWS else []
+    with xession.env.swap(PATH=str(bindir), PATHEXT=pathext):
+        assert locate_executable("file1.EXE")
+        assert locate_executable("nofile") is None
+        assert locate_executable("file5") is None
+        assert locate_executable("subdir") is None
+        if ON_WINDOWS:
+            assert locate_executable("file1")
+            assert locate_executable("file4")
+            assert locate_executable("file2").endswith("file2.exe")
+        else:
+            assert locate_executable("file3")
+            assert locate_executable("file1") is None
+            assert locate_executable("file4") is None
+            assert locate_executable("file2") is None

tests/prompt/test_vc.py

@@ -2,7 +2,6 @@ import os
 import subprocess as sp
 import textwrap
 from pathlib import Path
-from unittest.mock import Mock
 
 import pytest
 
@@ -119,27 +118,6 @@ current = yellow reverse
         assert not branch.startswith("\u001b[")
 
 
-def test_current_branch_calls_locate_binary_for_empty_cmds_cache(xession, monkeypatch):
-    cache = xession.commands_cache
-    monkeypatch.setattr(cache, "is_empty", Mock(return_value=True))
-    monkeypatch.setattr(cache, "locate_binary", Mock(return_value=""))
-    vc.current_branch()
-    assert cache.locate_binary.called
-
-
-def test_current_branch_does_not_call_locate_binary_for_non_empty_cmds_cache(
-    xession,
-    monkeypatch,
-):
-    cache = xession.commands_cache
-    monkeypatch.setattr(cache, "is_empty", Mock(return_value=False))
-    monkeypatch.setattr(cache, "locate_binary", Mock(return_value=""))
-    # make lazy locate return nothing to avoid running vc binaries
-    monkeypatch.setattr(cache, "lazy_locate_binary", Mock(return_value=""))
-    vc.current_branch()
-    assert not cache.locate_binary.called
-
-
 def test_dirty_working_directory(repo, set_xenv):
     get_dwd = "{}_dirty_working_directory".format(repo["vc"])
     set_xenv(repo["dir"])

tests/test_commands_cache.py

@@ -1,6 +1,8 @@
 import os
 import pickle
+import stat
 import time
+from tempfile import TemporaryDirectory
 
 import pytest
 
@@ -8,12 +10,16 @@ from xonsh.commands_cache import (
     SHELL_PREDICTOR_PARSER,
     CommandsCache,
     _Commands,
+    executables_in,
     predict_false,
     predict_shell,
     predict_true,
 )
+from xonsh.platform import ON_WINDOWS
 from xonsh.pytest.tools import skip_if_on_windows
 
+PATHEXT_ENV = {"PATHEXT": [".COM", ".EXE", ".BAT"]}
+
 
 def test_commands_cache_lazy(xession):
     cc = xession.commands_cache
@@ -260,3 +266,43 @@ def test_nixos_coreutils(tmp_path):
 
     assert cache.predict_threadable(["echo", "1"]) is True
     assert cache.predict_threadable(["cat", "file"]) is False
+
+
+def test_executables_in(xession):
+    expected = set()
+    types = ("file", "directory", "brokensymlink")
+    if ON_WINDOWS:
+        # Don't test symlinks on windows since it requires admin
+        types = ("file", "directory")
+    executables = (True, False)
+    with TemporaryDirectory() as test_path:
+        for _type in types:
+            for executable in executables:
+                fname = f"{_type}_{executable}"
+                if _type == "none":
+                    continue
+                if _type == "file" and executable:
+                    ext = ".exe" if ON_WINDOWS else ""
+                    expected.add(fname + ext)
+                else:
+                    ext = ""
+                path = os.path.join(test_path, fname + ext)
+                if _type == "file":
+                    with open(path, "w") as f:
+                        f.write(fname)
+                elif _type == "directory":
+                    os.mkdir(path)
+                elif _type == "brokensymlink":
+                    tmp_path = os.path.join(test_path, "i_wont_exist")
+                    with open(tmp_path, "w") as f:
+                        f.write("deleteme")
+                        os.symlink(tmp_path, path)
+                    os.remove(tmp_path)
+                if executable and not _type == "brokensymlink":
+                    os.chmod(path, stat.S_IXUSR | stat.S_IRUSR | stat.S_IWUSR)
+            if ON_WINDOWS:
+                xession.env = PATHEXT_ENV
+                result = set(executables_in(test_path))
+            else:
+                result = set(executables_in(test_path))
+    assert expected == result

tests/test_integrations.py

@@ -729,8 +729,11 @@ def test_script(case):
     if ON_DARWIN:
         script = script.replace("tests/bin", str(Path(__file__).parent / "bin"))
     out, err, rtn = run_xonsh(script)
+    out = out.replace("bash: no job control in this shell\n", "")
     if callable(exp_out):
-        assert exp_out(out)
+        assert exp_out(
+            out
+        ), f"CASE:\nscript=***\n{script}\n***,\nExpected: {exp_out!r},\nActual: {out!r}"
     else:
         assert exp_out == out
     assert exp_rtn == rtn

tests/test_tools.py

@@ -4,10 +4,8 @@ import datetime as dt
 import os
 import pathlib
 import re
-import stat
 import subprocess
 import warnings
-from tempfile import TemporaryDirectory
 
 import pytest
 
@@ -35,7 +33,6 @@ from xonsh.tools import (
     ensure_timestamp,
     env_path_to_str,
     escape_windows_cmd_string,
-    executables_in,
     expand_case_matching,
     expand_path,
     expandvars,
@@ -101,7 +98,6 @@ INDENT = "    "
 
 TOOLS_ENV = {"EXPAND_ENV_VARS": True, "XONSH_ENCODING_ERRORS": "strict"}
 ENCODE_ENV_ONLY = {"XONSH_ENCODING_ERRORS": "strict"}
-PATHEXT_ENV = {"PATHEXT": [".COM", ".EXE", ".BAT"]}
 
 
 def test_random_choice():
@@ -1616,46 +1612,6 @@ def test_partial_string(leaders, prefix, quote):
     assert obs == exp
 
 
-def test_executables_in(xession):
-    expected = set()
-    types = ("file", "directory", "brokensymlink")
-    if ON_WINDOWS:
-        # Don't test symlinks on windows since it requires admin
-        types = ("file", "directory")
-    executables = (True, False)
-    with TemporaryDirectory() as test_path:
-        for _type in types:
-            for executable in executables:
-                fname = f"{_type}_{executable}"
-                if _type == "none":
-                    continue
-                if _type == "file" and executable:
-                    ext = ".exe" if ON_WINDOWS else ""
-                    expected.add(fname + ext)
-                else:
-                    ext = ""
-                path = os.path.join(test_path, fname + ext)
-                if _type == "file":
-                    with open(path, "w") as f:
-                        f.write(fname)
-                elif _type == "directory":
-                    os.mkdir(path)
-                elif _type == "brokensymlink":
-                    tmp_path = os.path.join(test_path, "i_wont_exist")
-                    with open(tmp_path, "w") as f:
-                        f.write("deleteme")
-                        os.symlink(tmp_path, path)
-                    os.remove(tmp_path)
-                if executable and not _type == "brokensymlink":
-                    os.chmod(path, stat.S_IXUSR | stat.S_IRUSR | stat.S_IWUSR)
-            if ON_WINDOWS:
-                xession.env = PATHEXT_ENV
-                result = set(executables_in(test_path))
-            else:
-                result = set(executables_in(test_path))
-    assert expected == result
-
-
 @pytest.mark.parametrize(
     "inp, exp",
     [

xonsh/aliases.py

@@ -31,6 +31,7 @@ from xonsh.platform import (
     ON_OPENBSD,
     ON_WINDOWS,
 )
+from xonsh.procs.executables import locate_file
 from xonsh.procs.jobs import bg, clean_jobs, disown, fg, jobs
 from xonsh.procs.specs import SpecAttrModifierAlias, SpecModifierAlias
 from xonsh.timings import timeit_alias
@@ -637,7 +638,7 @@ def source_alias(args, stdin=None):
     for i, fname in enumerate(args):
         fpath = fname
         if not os.path.isfile(fpath):
-            fpath = locate_binary(fname)
+            fpath = locate_file(fname)
             if fpath is None:
                 if env.get("XONSH_DEBUG"):
                     print(f"source: {fname}: No such file", file=sys.stderr)

xonsh/commands_cache.py

@@ -16,7 +16,12 @@ from pathlib import Path
 
 from xonsh.lib.lazyasd import lazyobject
 from xonsh.platform import ON_POSIX, ON_WINDOWS, pathbasename
-from xonsh.tools import executables_in
+from xonsh.procs.executables import (
+    get_paths,
+    get_possible_names,
+    is_executable_in_posix,
+    is_executable_in_windows,
+)
 
 if ON_WINDOWS:
     from case_insensitive_dict import CaseInsensitiveDict as CacheDict
@@ -29,12 +34,58 @@ class _Commands(tp.NamedTuple):
     cmds: "tuple[str, ...]"
 
 
+def _yield_accessible_unix_file_names(path):
+    """yield file names of executable files in path."""
+    if not os.path.exists(path):
+        return
+    for file_ in os.scandir(path):
+        if is_executable_in_posix(file_):
+            yield file_.name
+
+
+def _executables_in_posix(path):
+    if not os.path.exists(path):
+        return
+    else:
+        yield from _yield_accessible_unix_file_names(path)
+
+
+def _executables_in_windows(path):
+    if not os.path.isdir(path):
+        return
+    try:
+        for x in os.scandir(path):
+            if is_executable_in_windows(x):
+                yield x.name
+    except FileNotFoundError:
+        # On Windows, there's no guarantee for the directory to really
+        # exist even if isdir returns True. This may happen for instance
+        # if the path contains trailing spaces.
+        return
+
+
+def executables_in(path) -> tp.Iterable[str]:
+    """Returns a generator of files in path that the user could execute."""
+    if ON_WINDOWS:
+        func = _executables_in_windows
+    else:
+        func = _executables_in_posix
+    try:
+        yield from func(path)
+    except PermissionError:
+        return
+
+
 class CommandsCache(cabc.Mapping):
     """A lazy cache representing the commands available on the file system.
     The keys are the command names and the values a tuple of (loc, has_alias)
     where loc is either a str pointing to the executable on the file system or
     None (if no executable exists) and has_alias is a boolean flag for whether
     the command has an alias.
+
+    Note! There is ``xonsh.procs.executables`` module with resolving executables.
+    Usage ``executables`` is preferred instead of commands_cache for cases
+    where you just need to locate executable command.
     """
 
     CACHE_FILE = "path-commands-cache.pickle"
@@ -99,25 +150,7 @@ class CommandsCache(cabc.Mapping):
         return len(self._cmds_cache) == 0
 
     def get_possible_names(self, name):
-        """Expand name to all possible variants based on `PATHEXT`.
+        return get_possible_names(name, self.env)
-
-        PATHEXT is a Windows convention containing extensions to be
-        considered when searching for an executable file.
-
-        Conserves order of any extensions found and gives precedence
-        to the bare name.
-        """
-        extensions = [""] + self.env.get("PATHEXT", [])
-        return [name + ext for ext in extensions]
-
-    @staticmethod
-    def remove_dups(paths):
-        cont = set()
-        for p in map(os.path.realpath, paths):
-            if p not in cont:
-                cont.add(p)
-                if os.path.isdir(p):
-                    yield p
 
     def _update_aliases_cache(self):
         """Update aliases checksum and return result: updated or not."""
@@ -162,10 +195,15 @@ class CommandsCache(cabc.Mapping):
         return current_path
 
     def update_cache(self):
+        """The main function to update commands cache.
+        Note! There is ``xonsh.procs.executables`` module with resolving executables.
+        Usage ``executables`` is preferred instead of commands_cache for cases
+        where you just need to locate executable command.
+        """
         env = self.env
         # iterate backwards so that entries at the front of PATH overwrite
         # entries at the back.
-        paths = tuple(reversed(tuple(self.remove_dups(env.get("PATH") or []))))
+        paths = get_paths(env)
         if self._update_and_check_changes(paths):
             all_cmds = CacheDict()
             for cmd, path in self._iter_binaries(paths):
@@ -256,6 +294,9 @@ class CommandsCache(cabc.Mapping):
     def locate_binary(self, name, ignore_alias=False):
         """Locates an executable on the file system using the cache.
 
+        NOT RECOMMENDED. Take a look into `xonsh.procs.executables.locate_executable`
+        before using this function.
+
         Parameters
         ----------
         name : str
@@ -270,6 +311,9 @@ class CommandsCache(cabc.Mapping):
     def lazy_locate_binary(self, name, ignore_alias=False):
         """Locates an executable in the cache, without checking its validity.
 
+        NOT RECOMMENDED. Take a look into `xonsh.procs.executables.locate_executable`
+        before using this function.
+
         Parameters
         ----------
         name : str

xonsh/completers/commands.py

@@ -4,8 +4,8 @@ import re
 import typing as tp
 
 import xonsh.platform as xp
-import xonsh.tools as xt
 from xonsh.built_ins import XSH
+from xonsh.commands_cache import executables_in
 from xonsh.completer import Completer
 from xonsh.completers.tools import (
     RichCompletion,
@@ -35,12 +35,12 @@ def complete_command(command: CommandContext):
                 kwargs["description"] = "Alias" if is_alias else path
             yield RichCompletion(s, append_space=True, **kwargs)
     if xp.ON_WINDOWS:
-        for i in xt.executables_in("."):
+        for i in executables_in("."):
             if i.startswith(cmd):
                 yield RichCompletion(i, append_space=True)
     base = os.path.basename(cmd)
     if os.path.isdir(base):
-        for i in xt.executables_in(base):
+        for i in executables_in(base):
             if i.startswith(cmd):
                 yield RichCompletion(os.path.join(base, i))
 

xonsh/environ.py

@@ -54,7 +54,6 @@ from xonsh.tools import (
     dynamic_cwd_tuple_to_str,
     ensure_string,
     env_path_to_str,
-    executables_in,
     history_tuple_to_str,
     intensify_colors_on_win_setter,
     is_bool,
@@ -2547,22 +2546,13 @@ class InternalEnvironDict(ChainMap):
         local.update(new_local)
 
 
-def _yield_executables(directory, name):
-    if ON_WINDOWS:
-        base_name, ext = os.path.splitext(name.lower())
-        for fname in executables_in(directory):
-            fbase, fext = os.path.splitext(fname.lower())
-            if base_name == fbase and (len(ext) == 0 or ext == fext):
-                yield os.path.join(directory, fname)
-    else:
-        for x in executables_in(directory):
-            if x == name:
-                yield os.path.join(directory, name)
-                return
-
-
 def locate_binary(name):
-    """Locates an executable on the file system."""
+    """Locates an executable on the file system.
+
+    NOT RECOMMENDED because ``commands_cache.locate_binary`` contains ``update_cache``
+    with scanning all files in ``$PATH``. First of all take a look into ``xonsh.specs.executables``
+    for more fast implementation the locate operation.
+    """
     return XSH.commands_cache.locate_binary(name)
 
 

xonsh/lib/itertools.py

@@ -1,3 +1,6 @@
+from itertools import filterfalse
+
+
 def as_iterable(iterable_or_scalar):
     """Utility for converting an object to an iterable.
     Parameters
@@ -34,3 +37,26 @@ def as_iterable(iterable_or_scalar):
         return iterable_or_scalar
     else:
         return (iterable_or_scalar,)
+
+
+def unique_everseen(iterable, key=None):
+    """Yield unique elements, preserving order. Remember all elements ever seen.
+
+    ```
+    unique_everseen('AAAABBBCCDAABBB') → A B C D
+    unique_everseen('ABBcCAD', str.casefold) → A B c D
+    ```
+
+    Source code: https://docs.python.org/3/library/itertools.html#itertools-recipes
+    """
+    seen = set()
+    if key is None:
+        for element in filterfalse(seen.__contains__, iterable):
+            seen.add(element)
+            yield element
+    else:
+        for element in iterable:
+            k = key(element)
+            if k not in seen:
+                seen.add(k)
+                yield element

xonsh/procs/executables.py

@@ -0,0 +1,103 @@
+"""Interfaces to locate executable files on file system."""
+
+import itertools
+import os
+from pathlib import Path
+
+from xonsh.built_ins import XSH
+from xonsh.lib.itertools import unique_everseen
+from xonsh.platform import ON_WINDOWS
+
+
+def get_possible_names(name, env=None):
+    """Expand name to all possible variants based on `PATHEXT`.
+
+    PATHEXT is a Windows convention containing extensions to be
+    considered when searching for an executable file.
+
+    Conserves order of any extensions found and gives precedence
+    to the bare name.
+    """
+    env = env if env is not None else XSH.env
+    env_pathext = env.get("PATHEXT", [])
+    if not env_pathext:
+        return [name]
+    upper = name.upper() == name
+    extensions = [""] + env_pathext
+    return [name + (ext.upper() if upper else ext.lower()) for ext in extensions]
+
+
+def clear_paths(paths):
+    """Remove duplicates and nonexistent directories from paths."""
+    return filter(os.path.isdir, unique_everseen(map(os.path.realpath, paths)))
+
+
+def get_paths(env=None):
+    """Return tuple with deduplicated and existent paths from ``$PATH``."""
+    env = env if env is not None else XSH.env
+    return tuple(reversed(tuple(clear_paths(env.get("PATH") or []))))
+
+
+def is_executable_in_windows(filepath, env=None):
+    """Check the file is executable in Windows."""
+    filepath = Path(filepath)
+    try:
+        try:
+            if not filepath.is_file():
+                return False
+        except OSError:
+            return False
+
+        env = env if env is not None else XSH.env
+        return any(s.lower() == filepath.suffix.lower() for s in env.get("PATHEXT", []))
+    except FileNotFoundError:
+        # On Windows, there's no guarantee for the directory to really
+        # exist even if isdir returns True. This may happen for instance
+        # if the path contains trailing spaces.
+        return False
+
+
+def is_executable_in_posix(filepath):
+    """Check the file is executable in POSIX."""
+    try:
+        return filepath.is_file() and os.access(filepath, os.X_OK)
+    except OSError:
+        # broken Symlink are neither dir not files
+        pass
+    return False
+
+
+is_executable = is_executable_in_windows if ON_WINDOWS else is_executable_in_posix
+
+
+def locate_executable(name, env=None):
+    """Search executable binary name in ``$PATH`` and return full path."""
+    return locate_file(name, env=env, check_executable=True, use_pathext=True)
+
+
+def locate_file(name, env=None, check_executable=False, use_pathext=False):
+    """Search file name in ``$PATH`` and return full path.
+
+    Compromise. There is no way to get case sensitive file name without listing all files.
+    If the file name is ``CaMeL.exe`` and we found that ``camel.EXE`` exists there is no way
+    to get back the case sensitive name. We don't want to read the list of files in all ``$PATH``
+    directories because of performance reasons. So we're ok to get existent
+    but case insensitive (or different) result from resolver.
+    May be in the future file systems as well as Python Path will be smarter to get the case sensitive name.
+    The task for reading and returning case sensitive filename we give to completer in interactive mode
+    with ``commands_cache``.
+    """
+    env = env if env is not None else XSH.env
+    env_path = env.get("PATH", [])
+    paths = tuple(reversed(tuple(clear_paths(env_path))))
+    possible_names = get_possible_names(name, env) if use_pathext else [name]
+
+    for path, possible_name in itertools.product(paths, possible_names):
+        filepath = Path(path) / possible_name
+
+        try:
+            if check_executable and not is_executable(filepath):
+                continue
+            return str(filepath)
+        except PermissionError:
+            return

xonsh/procs/specs.py

@@ -12,13 +12,13 @@ import stat
 import subprocess
 import sys
 
-import xonsh.environ as xenv
 import xonsh.lib.lazyasd as xl
 import xonsh.lib.lazyimps as xli
 import xonsh.platform as xp
 import xonsh.procs.jobs as xj
 import xonsh.tools as xt
 from xonsh.built_ins import XSH
+from xonsh.procs.executables import locate_executable
 from xonsh.procs.pipelines import (
     STDOUT_CAPTURE_KINDS,
     CommandPipeline,
@@ -734,13 +734,13 @@ class SubprocSpec:
         alias = self.alias
         if alias is None:
             cmd0 = self.cmd[0]
-            binary_loc = xenv.locate_binary(cmd0)
+            binary_loc = locate_executable(cmd0)
-            if binary_loc == cmd0 and cmd0 in self.alias_stack:
+            if binary_loc is None and cmd0 and cmd0 in self.alias_stack:
                 raise Exception(f'Recursive calls to "{cmd0}" alias.')
         elif callable(alias):
             binary_loc = None
         else:
-            binary_loc = xenv.locate_binary(alias[0])
+            binary_loc = locate_executable(alias[0])
         self.binary_loc = binary_loc
 
     def resolve_auto_cd(self):

xonsh/prompt/vc.py

@@ -13,6 +13,7 @@ import threading
 import xonsh.tools as xt
 from xonsh.built_ins import XSH
 from xonsh.lib.lazyasd import LazyObject
+from xonsh.procs.executables import locate_executable
 
 RE_REMOVE_ANSI = LazyObject(
     lambda: re.compile(r"(?:\x1B[@-_]|[\x80-\x9F])[0-?]*[ -/]*[@-~]"),
@@ -169,11 +170,7 @@ def _first_branch_timeout_message():
 
 def _vc_has(binary):
     """This allows us to locate binaries after git only if necessary"""
-    cmds = XSH.commands_cache
+    return bool(locate_executable(binary))
-    if cmds.is_empty():
-        return bool(cmds.locate_binary(binary, ignore_alias=True))
-    else:
-        return bool(cmds.lazy_locate_binary(binary, ignore_alias=True))
 
 
 def current_branch():

xonsh/pyghooks.py

@@ -38,7 +38,6 @@ from xonsh.color_tools import (
     make_palette,
     warn_deprecated_no_color,
 )
-from xonsh.commands_cache import CommandsCache
 from xonsh.events import events
 from xonsh.lib.lazyasd import LazyDict, LazyObject, lazyobject
 from xonsh.lib.lazyimps import html, os_listxattr, terminal256
@@ -48,6 +47,7 @@ from xonsh.platform import (
     pygments_version_info,
     win_ansi_support,
 )
+from xonsh.procs.executables import locate_executable
 from xonsh.pygments_cache import add_custom_style, get_style_by_name
 from xonsh.style_tools import DEFAULT_STYLE_DICT, norm_name
 from xonsh.tools import (
@@ -1600,7 +1600,7 @@ def _command_is_valid(cmd):
         cmd_abspath = os.path.abspath(os.path.expanduser(cmd))
     except OSError:
         return False
-    return (cmd in XSH.commands_cache and not iskeyword(cmd)) or (
+    return ((cmd in XSH.aliases or locate_executable(cmd)) and not iskeyword(cmd)) or (
         os.path.isfile(cmd_abspath) and os.access(cmd_abspath, os.X_OK)
     )
 
@@ -1649,15 +1649,12 @@ class XonshLexer(Python3Lexer):
 
     def __init__(self, *args, **kwargs):
         # If the lexer is loaded as a pygment plugin, we have to mock
-        # __xonsh__.env and __xonsh__.commands_cache
+        # __xonsh__.env
         if getattr(XSH, "env", None) is None:
             XSH.env = {}
             if ON_WINDOWS:
                 pathext = os_environ.get("PATHEXT", [".EXE", ".BAT", ".CMD"])
                 XSH.env["PATHEXT"] = pathext.split(os.pathsep)
-        if getattr(XSH, "commands_cache", None) is None:
-            XSH.commands_cache = CommandsCache(XSH.env)
-        _ = XSH.commands_cache.all_commands  # NOQA
         super().__init__(*args, **kwargs)
 
     tokens = {

xonsh/pytest/plugin.py

@@ -132,8 +132,8 @@ def mock_executables_in(xession, tmp_path, monkeypatch):
 
 @pytest.fixture
 def patch_locate_binary(monkeypatch):
-    def locate_binary(self, name):
+    def locate_binary(self, name, *args):
-        return os.path.join(os.path.dirname(__file__), "bin", name)
+        return str(Path(__file__).parent.parent.parent / "tests" / "bin" / name)
 
     def factory(cc: commands_cache.CommandsCache):
         monkeypatch.setattr(cc, "locate_binary", types.MethodType(locate_binary, cc))

xonsh/tools.py

@@ -822,62 +822,6 @@ class redirect_stderr(_RedirectStream):
     _stream = "stderr"
 
 
-def _yield_accessible_unix_file_names(path):
-    """yield file names of executable files in path."""
-    if not os.path.exists(path):
-        return
-    for file_ in os.scandir(path):
-        try:
-            if file_.is_file() and os.access(file_.path, os.X_OK):
-                yield file_.name
-        except OSError:
-            # broken Symlink are neither dir not files
-            pass
-
-
-def _executables_in_posix(path):
-    if not os.path.exists(path):
-        return
-    else:
-        yield from _yield_accessible_unix_file_names(path)
-
-
-def _executables_in_windows(path):
-    if not os.path.isdir(path):
-        return
-    extensions = xsh.env["PATHEXT"]
-    try:
-        for x in os.scandir(path):
-            try:
-                is_file = x.is_file()
-            except OSError:
-                continue
-            if is_file:
-                fname = x.name
-            else:
-                continue
-            base_name, ext = os.path.splitext(fname)
-            if ext.upper() in extensions:
-                yield fname
-    except FileNotFoundError:
-        # On Windows, there's no guarantee for the directory to really
-        # exist even if isdir returns True. This may happen for instance
-        # if the path contains trailing spaces.
-        return
-
-
-def executables_in(path) -> tp.Iterable[str]:
-    """Returns a generator of files in path that the user could execute."""
-    if ON_WINDOWS:
-        func = _executables_in_windows
-    else:
-        func = _executables_in_posix
-    try:
-        yield from func(path)
-    except PermissionError:
-        return
-
-
 def debian_command_not_found(cmd):
     """Uses the debian/ubuntu command-not-found utility to suggest packages for a
     command that cannot currently be found.