Find clang-format with alternative names

This is similar to what we currently do for scan-build except there is
no environment variable to choose a specific clang-format to run. If an
environment variable is needed for better control, we can add it later.

mesonbuild/backend/ninjabackend.py

@@ -2657,9 +2657,8 @@ https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47485'''))
         self.create_target_alias('meson-scan-build')
 
     def generate_clangformat(self):
-        import shutil
         target_name = 'clang-format'
-        if shutil.which('clang-format') is None:
+        if not environment.detect_clangformat():
             return
         if not os.path.exists(os.path.join(self.environment.source_dir, '.clang-format')) and \
                 not os.path.exists(os.path.join(self.environment.source_dir, '_clang-format')):

mesonbuild/environment.py

@@ -189,7 +189,7 @@ def get_llvm_tool_names(tool: str) -> typing.List[str]:
         names.append(tool + suffix)
     return names
 
-def detect_scanbuild():
+def detect_scanbuild() -> typing.List[str]:
     """ Look for scan-build binary on build platform
 
     First, if a SCANBUILD env variable has been provided, give it precedence
@@ -220,6 +220,22 @@ def detect_scanbuild():
             return [tool]
     return []
 
+def detect_clangformat() -> typing.List[str]:
+    """ Look for clang-format binary on build platform
+
+    Do the same thing as detect_scanbuild to find clang-format except it
+    currently does not check the environment variable.
+
+    Return: a single-element list of the found clang-format binary ready to be
+        passed to Popen()
+    """
+    tools = get_llvm_tool_names('clang-format')
+    for tool in tools:
+        path = shutil.which(tool)
+        if path is not None:
+            return [path]
+    return []
+
 def detect_native_windows_arch():
     """
     The architecture of Windows itself: x86, amd64 or arm64

mesonbuild/scripts/clangformat.py

@@ -16,9 +16,10 @@ import pathlib
 import subprocess
 from concurrent.futures import ThreadPoolExecutor
 
+from ..environment import detect_clangformat
 from ..compilers import lang_suffixes
 
-def clangformat(srcdir_name, builddir_name):
+def clangformat(exelist, srcdir_name, builddir_name):
     srcdir = pathlib.Path(srcdir_name)
     suffixes = set(lang_suffixes['c']).union(set(lang_suffixes['cpp']))
     suffixes.add('h')
@@ -28,11 +29,17 @@ def clangformat(srcdir_name, builddir_name):
             strf = str(f)
             if strf.startswith(builddir_name):
                 continue
-            futures.append(e.submit(subprocess.check_call, ['clang-format', '-style=file', '-i', strf]))
+            futures.append(e.submit(subprocess.check_call, exelist + ['-style=file', '-i', strf]))
         [x.result() for x in futures]
     return 0
 
 def run(args):
     srcdir_name = args[0]
     builddir_name = args[1]
-    return clangformat(srcdir_name, builddir_name)
+
+    exelist = detect_clangformat()
+    if not exelist:
+        print('Could not execute clang-format "%s"' % ' '.join(exelist))
+        return 1
+
+    return clangformat(exelist, srcdir_name, builddir_name)