Omit CWD in executable search even when shell=True

Author: EliahKagan

Diff for: git/cmd.py

@@ -985,23 +985,31 @@ def execute(
         if inline_env is not None:
             env.update(inline_env)
 
+        if shell is None:
+            shell = self.USE_SHELL
+
+        cmd_not_found_exception = FileNotFoundError
+        maybe_patch_caller_env = contextlib.nullcontext()
+
         if os.name == "nt":
-            cmd_not_found_exception = OSError
             if kill_after_timeout is not None:
                 raise GitCommandError(
                     redacted_command,
                     '"kill_after_timeout" feature is not supported on Windows.',
                 )
-            # Only search PATH, not CWD. This must be in the *caller* environment. The "1" can be any value.
-            maybe_patch_caller_env = patch_env("NoDefaultCurrentDirectoryInExePath", "1")
-        else:
-            cmd_not_found_exception = FileNotFoundError
-            maybe_patch_caller_env = contextlib.nullcontext()
+
+            cmd_not_found_exception = OSError
+
+            # Search PATH, but do not search CWD. The "1" can be any value.
+            if shell:
+                # If the direct subprocess is a shell, this must go in its environment.
+                env["NoDefaultCurrentDirectoryInExePath"] = "1"
+            else:
+                # If we're not using a shell, the variable goes in our own environment.
+                maybe_patch_caller_env = patch_env("NoDefaultCurrentDirectoryInExePath", "1")
         # END handle
 
         stdout_sink = PIPE if with_stdout else getattr(subprocess, "DEVNULL", None) or open(os.devnull, "wb")
-        if shell is None:
-            shell = self.USE_SHELL
         log.debug(
             "Popen(%s, cwd=%s, stdin=%s, shell=%s, universal_newlines=%s)",
             redacted_command,