How to parse Java code in Python using ANTLRv4

Question

I'm trying to parse some Java code in Python using ANTLRv4. I've tried to follow this post, but I get the following error:

 File "/home/xxxxxxx/xxxxxxx/xxxxxxx/antlr/proto_antlr.py", line 14, in <module>
 main()
 File "/home/xxxxxxx/xxxxxxx/xxxxxxx/antlr/proto_antlr.py", line 9, in main
 tree = parser.compilationUnit()
 File "/home/xxxxxxx/xxxxxxx/xxxxxxx/antlr/Java8Parser.py", line 4182, in compilationUnit
 self.enterRule(localctx, 62, self.RULE_compilationUnit)
 File "/home/xxxxxxx/xxxxxxx/xxxxxxx/lib/python3.8/site-packages/antlr4/Parser.py", line 374, in enterRule
 self._ctx.start = self._input.LT(1)
 File "/home/xxxxxxx/xxxxxxx/xxxxxxx/lib/python3.8/site-packages/antlr4/CommonTokenStream.py", line 62, in LT
 self.lazyInit()
 File "/home/xxxxxxx/xxxxxxx/xxxxxxx/lib/python3.8/site-packages/antlr4/BufferedTokenStream.py", line 187, in lazyInit
 self.setup()
 File "/home/xxxxxxx/xxxxxxx/xxxxxxx/lib/python3.8/site-packages/antlr4/BufferedTokenStream.py", line 190, in setup
 self.sync(0)
 File "/home/xxxxxxx/xxxxxxx/xxxxxxx/lib/python3.8/site-packages/antlr4/BufferedTokenStream.py", line 112, in sync
 fetched = self.fetch(n)
 File "/home/xxxxxxx/xxxxxxx/xxxxxxx/lib/python3.8/site-packages/antlr4/BufferedTokenStream.py", line 124, in fetch
 t = self.tokenSource.nextToken()
 File "/home/xxxxxxx/xxxxxxx/xxxxxxx/lib/python3.8/site-packages/antlr4/Lexer.py", line 130, in nextToken
 self._tokenStartLine = self._interp.line_number
AttributeError: 'LexerATNSimulator' object has no attribute 'line_number'

I can't figure out what I'm doing wrong. The file I'm trying to parse is proper Java, it's extracted from the docker-maven-plugin package. I've tried with other files, but I get the same error.

Any idea ?

• CocoNess: AttributeError: 'LexerATNSimulator' object has no attribute 'line_number'
• Thomas Kläger: Which version of antlr4 do you use to create the parser? Which version of the antlr4-python3-runtime do you use to run the generated parser?
• Thomas Kläger: How did you install the antlr4-python3-runtime? I couldn't find the string line_number in the antlr4-python3-runtime packages that I inspected (downloaded from pypi, versions 4.9.2 and 4.8)
• Thomas Kläger: Note that this is not a problem with the java code that you are trying to parse - this is a problem with the antlr4 runtime where one class of the antlr4 runtime (antlr4.Lexer) tries to access an attribute in another class of the antlr4 runtime (antlr4.atn.LexerATNSimulator) that doesn't exist.
• Kahsius: @ThomasKläger I'm using antlr 4.9.2 and antlr4-python3-runtime 4.9.2 downloaded using pip install. If you have any working duo of versions, I can try it.

Answer 1

Actually it was just a problem of violent refactorization... I've changed line to line_number in my code, and it actually changed it in librairies too. Changing it back to line cleared the problem.

Thanks to @Thomas Kläger for making me realize it.