bugfix: Fix temp file resource leak in find_missing.py

Summary:
Both `find_defs()` and `find_decls()` create temporary pattern files in /tmp
using a predictable name with `random.randint(0, 1024)` but never clean them
up after use. This causes temp file accumulation and also risks collisions
due to the small random range (only 1024 possible filenames).

Replaced manual temp file creation with `tempfile.NamedTemporaryFile` for
unique naming, and added `try/finally` blocks to ensure the files are always
cleaned up. Also removed the now-unused `random` import.

Reviewed By: yoney

Differential Revision: D99294378

fbshipit-source-id: e7d194d258ff97b51587dc456dcfa16d5dbc9df7

Author: alexmalyshev

cinderx/UpstreamBorrow/find_missing.py

@@ -13,9 +13,9 @@
 import json
 import os
 import os.path
-import random
 import subprocess
 import sys
+import tempfile
 from collections import defaultdict
 from typing import Iterable
 
@@ -82,24 +82,29 @@ def find_defs(syms: Iterable[str]) -> dict[str, list[str]]:
     # so we can search for "^symbol" to distinguish definitions from function
     # calls.
 
-    patfile = "/tmp/patterns-" + str(random.randint(0, 1024))
-    with open(patfile, "w") as f:
+    with tempfile.NamedTemporaryFile(
+        mode="w", suffix=".txt", prefix="patterns_", delete=False
+    ) as f:
+        patfile = f.name
         for sym in syms:
             f.write(f"^{sym}\\b\n")
-    # We need to grep over the cpython base dir
-    path = os.path.join(get_fbsource_root(), "third-party/python/3.12")
-    ret = run(["grep", "-oHR", "-f", patfile, path])
-    out = defaultdict(list)
-    seen = set()  # make sure each symbol has a single definition
-    for line in ret.strip().split("\n"):
-        file, sym = line.split(":")
-        if not file.endswith(".c"):
-            continue
-        if sym in seen:
-            raise RuntimeError(f"Multiple definitions found for {sym}")
-        seen.add(sym)
-        out[file.lstrip("./")].append(sym)
-    return out
+    try:
+        # We need to grep over the cpython base dir
+        path = os.path.join(get_fbsource_root(), "third-party/python/3.12")
+        ret = run(["grep", "-oHR", "-f", patfile, path])
+        out = defaultdict(list)
+        seen = set()  # make sure each symbol has a single definition
+        for line in ret.strip().split("\n"):
+            file, sym = line.split(":")
+            if not file.endswith(".c"):
+                continue
+            if sym in seen:
+                raise RuntimeError(f"Multiple definitions found for {sym}")
+            seen.add(sym)
+            out[file.lstrip("./")].append(sym)
+        return out
+    finally:
+        os.unlink(patfile)
 
 
 def find_decls(syms: Iterable[str]) -> dict[str, list[int]]:
@@ -110,25 +115,30 @@ def find_decls(syms: Iterable[str]) -> dict[str, list[int]]:
     # with a pattern file. If this is an issue, modify the pattern below to use
     # grep character classes instead.
 
-    patfile = "/tmp/patterns-" + str(random.randint(0, 1024))
-    with open(patfile, "w") as f:
+    with tempfile.NamedTemporaryFile(
+        mode="w", suffix=".txt", prefix="patterns_", delete=False
+    ) as f:
+        patfile = f.name
         for sym in syms:
             f.write(rf"^(\w[\w\s*]*)?\b{sym}\b" + "\n")
-    # We need to grep over the cpython base dir
-    path = os.path.join(get_fbsource_root(), "third-party/python/3.12/Include")
-    ret = run(["rg", "-n", "-f", patfile, path])
-    if not ret:
-        # No missing symbols found
-        return {}
-    out = defaultdict(list)
-    for line in ret.strip().split("\n"):
-        file, lineno, decl = line.split(":", 3)
-        if not file.endswith(".h"):
-            continue
-        if decl.startswith(" ") or decl.startswith("PyAPI_"):
-            continue
-        out[file].append(int(lineno))
-    return out
+    try:
+        # We need to grep over the cpython base dir
+        path = os.path.join(get_fbsource_root(), "third-party/python/3.12/Include")
+        ret = run(["rg", "-n", "-f", patfile, path])
+        if not ret:
+            # No missing symbols found
+            return {}
+        out = defaultdict(list)
+        for line in ret.strip().split("\n"):
+            file, lineno, decl = line.split(":", 3)
+            if not file.endswith(".h"):
+                continue
+            if decl.startswith(" ") or decl.startswith("PyAPI_"):
+                continue
+            out[file].append(int(lineno))
+        return out
+    finally:
+        os.unlink(patfile)
 
 
 def find_missing_symbols() -> set[str]: