[Code scan] MultiSystems.from_dir silently returns empty results for absolute directories

[njzjz]

This issue is part of a Codex global repository code scan.

MultiSystems.from_dir() prepends ./ to dir_name before globbing. When dir_name is already absolute, the search path becomes relative to the current working directory, so valid absolute directories can silently return an empty MultiSystems.

Affected code:

dpdata/dpdata/system.py

Lines 1478 to 1492 in a7a50bf

	def from_dir(
	cls,
	dir_name: str,
	file_name: str,
	fmt: str = "auto",
	type_map: list[str] | None = None,
	):
	multi_systems = cls()
	target_file_list = sorted(
	glob.glob(f"./{dir_name}/**/{file_name}", recursive=True)
	)
	for target_file in target_file_list:
	multi_systems.append(
	LabeledSystem(file_name=target_file, fmt=fmt, type_map=type_map)
	)

Minimal reproducer from the repository root:

from pathlib import Path
import dpdata

rel = dpdata.MultiSystems.from_dir("tests/poscars", "OUTCAR.h2o.md", fmt="vasp/outcar")
print("relative", len(rel), rel.get_nframes())

absdir = str(Path("tests/poscars").resolve())
abs_ms = dpdata.MultiSystems.from_dir(absdir, "OUTCAR.h2o.md", fmt="vasp/outcar")
print("absolute", len(abs_ms), abs_ms.get_nframes())

Current output:

relative 1 3
absolute 0 0

Expected behavior: absolute and relative directory arguments should search the same target directory and return the same systems.

[dosubot]

The bug is confirmed. The issue is on line 1486 where the glob pattern is constructed as:

glob.glob(f"./{dir_name}/**/{file_name}", recursive=True)

The hardcoded ./ prefix makes the pattern nonsensical for absolute paths (e.g., .//home/user/data/**/OUTCAR).

A minimal fix would be to simply drop the ./ prefix:

target_file_list = sorted(
    glob.glob(f"{dir_name}/**/{file_name}", recursive=True)
)

This works correctly for both relative and absolute paths. Alternatively, using os.path.join would be slightly more robust:

import os
target_file_list = sorted(
    glob.glob(os.path.join(dir_name, "**", file_name), recursive=True)
)

The os.path.join approach mirrors the pattern used in PR #172 which fixed similar path construction issues in from_multi_systems.

To reply, just mention @dosu.

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