Further refine black_bindings

Author: jepler

tools/black_bindings.py

@@ -6,24 +6,32 @@
 import sys
 
 
-def transform(s):
+def transform(fn, s):
     lines = s.rstrip().split("\n")
     lines = [line.removeprefix("//| ").removeprefix("//|") for line in lines]
+    while lines and not lines[0]:
+        del lines[0]
+
     s = "\n".join(lines) + "\n"
     if s[0] == " ":
         prefix = "if 0:\n"
     else:
         prefix = ""
     s = prefix + s
-    result = subprocess.run(
-        ["black", "-q", "--pyi", "-"],
-        input=s,
-        check=True,
-        stdout=subprocess.PIPE,
-        encoding="utf-8",
-    )
+    try:
+        result = subprocess.run(
+            ["black", "-q", "--pyi", "-"],
+            input=s,
+            check=True,
+            stdout=subprocess.PIPE,
+            encoding="utf-8",
+        )
+    except subprocess.CalledProcessError as e:
+        print(f"{fn}:0: Failed to process block:\n{s}")
+        return s
+
     result = result.stdout[len(prefix) :]
-    result = (result.rstrip() + "\n").split("\n")
+    result = (result.rstrip()).split("\n")
     return "\n".join("//| " + line if line else "//|" for line in result) + "\n"
 
 
@@ -33,20 +41,23 @@ def process_one_file(fn):
 
     old_end = 0
 
-    newcontent = []
-    for m in re.finditer("(?m)((?:^//\|.*\n)+)", content):
-        newcontent.append(content[old_end : m.start()])
-        newcontent.append(transform(m.group()))
+    parts = []
+    for m in re.finditer("(?m)((?:^//\|.*\n)(?:^//\|.*\n|^\n)*)", content):
+        parts.append(content[old_end : m.start()])
+        parts.append(transform(fn, m.group()))
         old_end = m.end()
-    newcontent.append(content[old_end:])
+    parts.append(content[old_end:])
+    newcontent = "".join(parts)
 
-    with open(fn, "w", encoding="utf-8") as f:
-        f.write("".join(newcontent))
+    if newcontent != content:
+        with open(fn, "w", encoding="utf-8") as f:
+            f.write(newcontent)
 
 
 if __name__ == "__main__":
     # Use a thread pool because most processing is inside black!
     executor = ThreadPoolExecutor(max_workers=os.cpu_count())
-    for fn in sys.argv[1:]:
-        executor.submit(process_one_file, fn)
+    futures = [executor.submit(process_one_file, fn) for fn in sys.argv[1:]]
+    for f in futures:
+        f.result()
     executor.shutdown()