I need to extract method implementation from java projects. I found a code on the javalang github issues https://github.com/c2nes/javalang/issues/49 but it fails sometimes. Can anyone take a look and see whats wrong?

On a colab notebook, clone the repo with

!git clone https://github.com/google/closure-compiler

Install javalang

!pip install javalang

Run the following code (it fails on other files too, not on every function but some)

import os
import re
import javalang
import json

def get_method_start_end(tree, method_node):
    startpos = None
    endpos = None
    startline = None
    endline = None
    for path, node in tree:
        if startpos is not None and method_node not in path:
            endpos = node.position
            endline = node.position.line if node.position is not None else None
            break
        if startpos is None and node == method_node:
            startpos = node.position
            startline = node.position.line if node.position is not None else None
    return startpos, endpos, startline, endline

def get_method_text(codelines, startpos, endpos, startline, endline, last_endline_index):
    if startpos is None:
        return "", None, None, None
    else:
        startline_index = startline - 1
        endline_index = endline - 1 if endpos is not None else None

        # 1. check for and fetch annotations
        if last_endline_index is not None:
            for line in codelines[(last_endline_index + 1):(startline_index)]:
                if "@" in line:
                    startline_index = startline_index - 1

        # 2. Add comments before method
        comments = []
        for line_index in range(startline_index - 1, -1, -1):
            line = codelines[line_index].strip()
            if line.startswith('//') or line.startswith('/*'):
                comments.insert(0, line)
            else:
                break

        method_lines = comments + codelines[startline_index:endline_index]
        method_text = 'n'.join(method_lines)
        method_text = method_text[:method_text.rfind("}") + 1]

        # 3. remove trailing rbrace for last methods & any external content/comments
        # if endpos is None and
        if not abs(method_text.count("}") - method_text.count("{")) == 0:
            # imbalanced braces
            brace_diff = abs(method_text.count("}") - method_text.count("{"))

            for _ in range(brace_diff):
                method_text = method_text[:method_text.rfind("}")]
                method_text = method_text[:method_text.rfind("}") + 1]

        last_endline_index = startline_index + len(method_lines) - 1

        return method_text, (startline_index + 1), (last_endline_index + 1), last_endline_index

def get_methods_info(java_content, file_path):
    code_lines = java_content.split('n')
    lex = None
    try:
        tree = javalang.parse.parse(java_content)
    except:
        print(f'Parsing failed for file: {file_path}')
        return None
    for _, method_node in tree.filter(javalang.tree.MethodDeclaration):

        startpos, endpos, startline, endline = get_method_start_end(tree, method_node)
        if endpos == None:
            raise ValueError(f"Check file: {file_path}, {method_node.name}")
            continue
        method_text, startline, endline, lex = get_method_text(code_lines, startpos, endpos, startline, endline, lex)
    return method_text

filename = "./closure-compiler/test/com/google/javascript/jscomp/Es6RewriteBlockScopedFunctionDeclarationTest.java"

with open(filename, 'r') as f:
    java_content = f.read()
    java_content = java_content.replace("@Nullable", "")
    java_content = java_content.replace(r"\$", "")

    java_content = re.sub(r'[^a-zA-Z](.+?)::new', lambda match: match.group(1).lower().removesuffix('[]'), java_content)

    methods_info = get_methods_info(java_content, filename)