Randomness in CodeBLEU computation

[iCSawyer]

CodeXGLUE/Code-Code/code-to-code-trans/evaluator/CodeBLEU/dataflow_match.py

Line 100 in 6744a7f

dic[d[1]]=(d[0],d[1],d[2],list(set(dic[d[1]][3]+d[3])),list(set(dic[d[1]][4]+d[4])))

The result of list(set()) is random under some circumstances. It can be easily reproduced by running python -c 'print(list(set(["fa", "dsa", "dsa", "w"])))'.

---

In some cases, the code snippet above can result in the difference of DFG returned by get_data_flow() and cause varying CodeBLUE scores (specifically dataflow_match_score):

CodeXGLUE/Code-Code/code-to-code-trans/evaluator/CodeBLEU/calc_code_bleu.py

Lines 64 to 67 in 6744a7f

	dataflow_match_score = dataflow_match.corpus_dataflow_match(references, hypothesis, args.lang)
	print('ngram match: {0}, weighted ngram match: {1}, syntax_match: {2}, dataflow_match: {3}'.\
	format(ngram_match_score, weighted_ngram_match_score, syntax_match_score, dataflow_match_score))

---

I have compared these two functions and found that in GraphCodeBERT there is no "merge nodes" action.

https://github.com/microsoft/CodeBERT/blob/ac04c77ca7cda9dc757dc8b4360e358731c8708e/GraphCodeBERT/codesearch/run.py#L68-L104

CodeXGLUE/Code-Code/code-to-code-trans/evaluator/CodeBLEU/dataflow_match.py

Lines 64 to 105 in 6744a7f

	def get_data_flow(code, parser):
	try:
	tree = parser[0].parse(bytes(code,'utf8'))
	root_node = tree.root_node
	tokens_index=tree_to_token_index(root_node)
	code=code.split('\n')
	code_tokens=[index_to_code_token(x,code) for x in tokens_index]
	index_to_code={}
	for idx,(index,code) in enumerate(zip(tokens_index,code_tokens)):
	index_to_code[index]=(idx,code)
	try:
	DFG,_=parser[1](root_node,index_to_code,{})
	except:
	DFG=[]
	DFG=sorted(DFG,key=lambda x:x[1])
	indexs=set()
	for d in DFG:
	if len(d[-1])!=0:
	indexs.add(d[1])
	for x in d[-1]:
	indexs.add(x)
	new_DFG=[]
	for d in DFG:
	if d[1] in indexs:
	new_DFG.append(d)
	codes=code_tokens
	dfg=new_DFG
	except:
	codes=code.split()
	dfg=[]
	#merge nodes
	dic={}
	for d in dfg:
	if d[1] not in dic:
	dic[d[1]]=d
	else:
	dic[d[1]]=(d[0],d[1],d[2],list(set(dic[d[1]][3]+d[3])),list(set(dic[d[1]][4]+d[4])))
	DFG=[]
	for d in dic:
	DFG.append(dic[d])
	dfg=DFG
	return dfg

---

My reference and candidate is:

  candidate = \
  '''
  throws IOException {
      int read = super.read(b, off, len);
      if (read > 0) {
          bytesRead.incrementAndGet();
      }
      return read;
  }
  '''
  reference = \
  '''
  throws IOException {
      // Obey InputStream contract.
      checkPositionIndexes(off, off + len, b.length);
      if (len == 0) {
      return 0;
      }

      // The rest of this method implements the process described by the CharsetEncoder javadoc.
      int totalBytesRead = 0;
      boolean doneEncoding = endOfInput;

      DRAINING:
      while (true) {
      // We stay in draining mode until there are no bytes left in the output buffer. Then we go
      // back to encoding/flushing.
      if (draining) {
          to
  '''

I was wondering if #104 ran into the same problem.

Thank you for your replying! @JiyangZhang @Imagist-Shuo @celbree

### Tasks

[ZeyuTeng96]

Hi,

I found the same problem as you addressed above. I think there are two solutions:

1. using list.extend or append func to add nodes
2. adding a sorted() func to it

Do you think is it feasible? We can make a PR to fix this together

[iCSawyer]

Hi,

I found the same problem as you addressed above. I think there are two solutions:

1. using list.extend or append func to add nodes
2. adding a sorted() func to it

Do you think is it feasible? We can make a PR to fix this together

I think your solution could work, and a PR for this is great 🤗

[ZeyuTeng96]

Hi, is it possible to make a PR for it. @celbree