test: Don't use shell=True in lint-files.py

Avoid the use of shell=True.

Author: laanwj

test/lint/lint-files.py

@@ -14,9 +14,10 @@
 from typing import Optional, NoReturn
 
 CMD_TOP_LEVEL = ["git", "rev-parse", "--show-toplevel"]
-CMD_ALL_FILES = "git ls-files -z --full-name"
-CMD_SOURCE_FILES = 'git ls-files -z --full-name -- "*.[cC][pP][pP]" "*.[hH]" "*.[pP][yY]" "*.[sS][hH]"'
-CMD_SHEBANG_FILES = "git grep --full-name --line-number -I '^#!'"
+CMD_ALL_FILES = ["git", "ls-files", "-z", "--full-name"]
+CMD_SOURCE_FILES = ["git", "ls-files", "-z", "--full-name", "--", "*.[cC][pP][pP]", "*.[hH]", "*.[pP][yY]", "*.[sS][hH]"]
+CMD_SHEBANG_FILES = ["git", "grep", "--full-name", "--line-number", "-I", "^#!"]
+
 ALLOWED_FILENAME_REGEXP = "^[a-zA-Z0-9/_.@][a-zA-Z0-9/_.@-]*$"
 ALLOWED_SOURCE_FILENAME_REGEXP = "^[a-z0-9_./-]+$"
 ALLOWED_SOURCE_FILENAME_EXCEPTION_REGEXP = (
@@ -73,7 +74,7 @@ def check_all_filenames() -> int:
     Checks every file in the repository against an allowed regexp to make sure only lowercase or uppercase
     alphanumerics (a-zA-Z0-9), underscores (_), hyphens (-), at (@) and dots (.) are used in repository filenames.
     """
-    filenames = check_output(CMD_ALL_FILES, shell=True).decode("utf8").rstrip("\0").split("\0")
+    filenames = check_output(CMD_ALL_FILES).decode("utf8").rstrip("\0").split("\0")
     filename_regex = re.compile(ALLOWED_FILENAME_REGEXP)
     failed_tests = 0
     for filename in filenames:
@@ -92,7 +93,7 @@ def check_source_filenames() -> int:
 
     Additionally there is an exception regexp for directories or files which are excepted from matching this regexp.
     """
-    filenames = check_output(CMD_SOURCE_FILES, shell=True).decode("utf8").rstrip("\0").split("\0")
+    filenames = check_output(CMD_SOURCE_FILES).decode("utf8").rstrip("\0").split("\0")
     filename_regex = re.compile(ALLOWED_SOURCE_FILENAME_REGEXP)
     filename_exception_regex = re.compile(ALLOWED_SOURCE_FILENAME_EXCEPTION_REGEXP)
     failed_tests = 0
@@ -111,7 +112,7 @@ def check_all_file_permissions() -> int:
 
     Additionally checks that for executable files, the file contains a shebang line
     """
-    filenames = check_output(CMD_ALL_FILES, shell=True).decode("utf8").rstrip("\0").split("\0")
+    filenames = check_output(CMD_ALL_FILES).decode("utf8").rstrip("\0").split("\0")
     failed_tests = 0
     for filename in filenames:
         file_meta = FileMeta(filename)
@@ -156,7 +157,7 @@ def check_shebang_file_permissions() -> int:
     """
     Checks every file that contains a shebang line to ensure it has an executable permission
     """
-    filenames = check_output(CMD_SHEBANG_FILES, shell=True).decode("utf8").strip().split("\n")
+    filenames = check_output(CMD_SHEBANG_FILES).decode("utf8").strip().split("\n")
 
     # The git grep command we use returns files which contain a shebang on any line within the file
     # so we need to filter the list to only files with the shebang on the first line