test driver: fix file collection for regex linters

When a testsuite linter is executed with the `tracked` strategy, the
driver runs `git ls-tree` to collect eligible files.

This appears to have ceased producing any paths – `ls-tree` restricts
its results to the current working directory, which is
`testsuite/tests/linters` in this case.

As a quick fix, this patch changes the working directory to match
expectations.

testsuite/tests/linters/Makefile

@@ -12,16 +12,16 @@ uniques:
 	python3 checkUniques/check-uniques.py $(TOP)/..
 
 makefiles:
-	(cd $(TOP)/tests/linters/ && python3 regex-linters/check-makefiles.py tracked)
+	(cd $(TOP)/.. && python3 testsuite/tests/linters/regex-linters/check-makefiles.py tracked)
 
 version-number:
 	regex-linters/check-version-number.sh ${TOP}/..
 
 cpp:
-	(cd $(TOP)/tests/linters/ && python3 regex-linters/check-cpp.py tracked)
+	(cd $(TOP)/.. && python3 testsuite/tests/linters/regex-linters/check-cpp.py tracked)
 
 rts-includes:
-	(cd $(TOP)/tests/linters/ && python3 regex-linters/check-rts-includes.py tracked)
+	(cd $(TOP)/.. && python3 testsuite/tests/linters/regex-linters/check-rts-includes.py tracked)
 
 changelogs:
 	regex-linters/check-changelogs.sh $(TOP)/..

testsuite/tests/linters/regex-linters/check-cpp.py

@@ -29,12 +29,6 @@ for l in linters:
     l.add_path_filter(lambda path: not path.name == 'config.guess')
     # Don't lint files from external xxhash projects
     l.add_path_filter(lambda path: path != Path('rts', 'xxhash.h')),
-    # Don't lint font files
-    l.add_path_filter(lambda path: not path.parent == Path('docs','users_guide',
-        'rtd-theme', 'static', 'fonts'))
-    # Don't lint image files
-    l.add_path_filter(lambda path: not path.parent == Path('docs','users_guide',
-        'images'))
     # Don't lint core spec
     l.add_path_filter(lambda path: not path.name == 'core-spec.pdf')
     # Don't lint the linter itself

testsuite/tests/linters/regex-linters/linter.py

@@ -40,6 +40,8 @@ def get_changed_files(base_commit: str, head_commit: str,
 
 def get_tracked_files(subdir: str = '.'):
     """ Get the files tracked by git in the given subdirectory. """
+    if not Path(subdir).exists():
+        raise Exception("Regex linter executed with nonexistent target directory '{}'".format(subdir))
     cmd = ['git', 'ls-tree', '--name-only', '-r', 'HEAD', subdir]
     files = subprocess.check_output(cmd)
     return files.decode('UTF-8').split('\n')
@@ -77,9 +79,16 @@ class LineLinter(Linter):
     """
     def lint(self, path: Path):
         if path.is_file():
-            with path.open('r') as f:
-                for line_no, line in enumerate(f):
-                    self.lint_line(path, line_no+1, line)
+            try:
+                with path.open('r') as f:
+                    for line_no, line in enumerate(f):
+                        self.lint_line(path, line_no+1, line)
+            # We don't want to explicitly exclude every single binary file in the test suite
+            except UnicodeDecodeError as e:
+                pass
+            except Exception as e:
+                print('Exception occurred while linting file: {}'.format(path))
+                raise e
 
     def lint_line(self, path: Path, line_no: int, line: str):
         raise NotImplementedError
@@ -124,7 +133,7 @@ def run_linters(linters: Sequence[Linter],
 
     linted_files = args.get_linted_files(args)
     for path in linted_files:
-        if path.startswith('linters'):
+        if path.startswith('testsuite/tests/linters'):
             continue
         for linter in linters:
             linter.do_lint(Path(path))