fix: resolve dotenv run commands against the .env PATH on Windows

CHANGELOG.md

@@ -14,6 +14,7 @@ project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - `set_key` and `unset_key` no longer leave a `.tmp_*` file behind on Windows when writing a read-only `.env` fails, and the error raised is the one from the failed write rather than from cleaning up the temporary file by [@MohammedAlkindi] in [#686]
 - `load_dotenv`, `dotenv_values`, `get_key`, `set_key`, `unset_key` and the CLI `--file` option now expand a leading `~` to the user's home directory by [@veeceey] in [#615]
 - `find_dotenv` and the IPython `%dotenv` magic now expand a leading `~` in the file name by [@theskumar] in [#714]
+- `dotenv run` on Windows now resolves the command against the `PATH` set in the `.env` file instead of ignoring it, so an activated virtualenv's interpreter is picked up by [@summeriver13] in [#730]
 
 ## [1.2.4] - 2026-10-01
 
@@ -467,6 +468,7 @@ os.PathLike]` instead of just `os.PathLike` (#347 by [@bbc2]).
 [#700]: https://github.com/theskumar/python-dotenv/pull/700
 [#711]: https://github.com/theskumar/python-dotenv/pull/711
 [#714]: https://github.com/theskumar/python-dotenv/pull/714
+[#730]: https://github.com/theskumar/python-dotenv/pull/730
 [790c5c0]: https://github.com/theskumar/python-dotenv/commit/790c5c02991100aa1bf41ee5330aca75edc51311
 
 <!-- contributors -->
@@ -520,6 +522,7 @@ os.PathLike]` instead of just `os.PathLike` (#347 by [@bbc2]).
 [@ShamikOfficial]: https://github.com/ShamikOfficial
 [@sidharth-sudhir]: https://github.com/sidharth-sudhir
 [@snobu]: https://github.com/snobu
+[@summeriver13]: https://github.com/summeriver13
 [@techalchemy]: https://github.com/techalchemy
 [@theGOTOguy]: https://github.com/theGOTOguy
 [@theskumar]: https://github.com/theskumar

src/dotenv/cli.py

@@ -1,6 +1,7 @@
 import json
 import os
 import shlex
+import shutil
 import sys
 from contextlib import contextmanager
 from typing import IO, Any, Dict, Iterator, List, Optional
@@ -237,9 +238,20 @@ def run_command(command: List[str], env: Dict[str, str]) -> None:
     if sys.platform == "win32":
         # execvpe on Windows returns control immediately
         # rather than once the command has finished.
+        #
+        # CreateProcess looks in the application directory before PATH, so a
+        # bare command name resolves to the executable that started this
+        # process rather than the first one on PATH (a virtualenv's python,
+        # for instance). Resolve it against the environment we are about to
+        # pass, which is not necessarily ours.
         try:
             p = Popen(
-                command, universal_newlines=True, bufsize=0, shell=False, env=cmd_env
+                command,
+                universal_newlines=True,
+                bufsize=0,
+                shell=False,
+                env=cmd_env,
+                executable=shutil.which(command[0], path=cmd_env.get("PATH")),
             )
         except FileNotFoundError:
             print(f"Command not found: {command[0]}", file=sys.stderr)

tests/test_cli.py

@@ -372,6 +372,33 @@ def test_run_with_env_missing_and_invalid_cmd(tmp_path):
     assert "Invalid value for '-f'" in result.stderr
 
 
+def test_run_resolves_command_using_dotenv_path(tmp_path):
+    """
+    Check that the command is resolved against the PATH built by `dotenv run`,
+    not the one of the calling process.
+
+    The command below is only reachable through the PATH set in the .env file.
+    Windows' CreateProcess looks up executables using the environment of the
+    calling process and ignores the environment it is handed, so this used to
+    fail there while working everywhere else.
+    """
+
+    bindir = tmp_path / "bin"
+    bindir.mkdir()
+    if sys.platform == "win32":
+        (bindir / "dotenv-test-cmd.bat").write_text("@echo dotenv-test-ok\r\n")
+    else:
+        cmd = bindir / "dotenv-test-cmd"
+        cmd.write_text("#!/bin/sh\necho dotenv-test-ok\n")
+        cmd.chmod(0o755)
+
+    (tmp_path / ".env").write_text(f"PATH={bindir}\n")
+
+    result = run_dotenv(["run", "dotenv-test-cmd"], cwd=tmp_path)
+
+    check_process(result, exit_code=0, stdout="dotenv-test-ok\n")
+
+
 def test_run_with_version(tmp_path):
     result = run_dotenv(["--version"], cwd=tmp_path)