Computes the AST difference between two Spoon abstract syntax trees using the Gumtree algorithm.
If you use this, please cite:
Fine-grained and Accurate Source Code Differencing (Jean-Rémy Falleri, Floréal Morandat, Xavier Blanc, Matias Martinez, Martin Monperrus), In Proceedings of the International Conference on Automated Software Engineering, 2014. DOI: 10.1145/2642937.2642982.
@inproceedings{gumtree,
title = {Fine-grained and Accurate Source Code Differencing},
author = {Falleri, Jean-R{\'e}my and Morandat, Flor{\'e}al and Blanc, Xavier and Martinez, Matias and Monperrus, Martin},
url = {https://hal.archives-ouvertes.fr/hal-01054552/file/main.pdf},
booktitle = {{Proceedings of the International Conference on Automated Software Engineering}},
pages = {313-324},
year = {2014},
doi = {10.1145/2642937.2642982},
}
What is the main difference between gumtree-spoon-ast-diff and gumtreediff?
changedNode
, commonAncestor
, getSrcNode
)The main class is used this way:
gumtree.spoon.AstComparator <file_1> <file_2>
As API:
new AstComparator().compare((CtElement) el1, (CtElement) el2);
new AstComparator().compare((File) f, (File) f2);
new AstComparator().compare((String) s1, (String) s2);
By default, the current version of Gumtree Spoon AST Diff uses the novel AST matcher called SimpleGumTree
. However, the API provides the possibility to change it: The mentioned compare
methods can also receive the configuration of the AST diff algorithm.
AstComparator comp = new AstComparator();
//We define a DiffConfiguration
DiffConfiguration diffConfiguration = new DiffConfiguration();
//Set the matcher to be used
diffConfiguration.setMatcher(new CompositeMatchers.ClassicGumtree());
//Set values for hyperparameters
GumtreeProperties properties = new GumtreeProperties();
properties.tryConfigure(ConfigurationOptions.bu_minsim, 0.2);
properties.tryConfigure(ConfigurationOptions.bu_minsize, 600);
properties.tryConfigure(ConfigurationOptions.st_minprio, 1);
properties.tryConfigure(ConfigurationOptions.st_priocalc, size);
diffConfiguration.setGumtreeProperties(properties);
//Now, compute the diff with the configuration diffConfiguration
Diff resultClassicMatcher = comp.compare(fl, fr, diffConfiguration);
In the previous snippet, we call the diff algorithm with a particular setup: ClassicGumtree matcher and a set of hyperparameters which minimize the size of the edit-scripts. The values of these hyperparameters were found using DAT (Diff Auto-Tuning).
@misc{dat,
author = {Martinez, Matias and Falleri, Jean-Rémy and Monperrus, Martin},
title = {Hyperparameter Optimization for AST Differencing},
publisher = {arXiv},
year = {2020},
doi = {10.48550/ARXIV.2011.10268},
url = {https://arxiv.org/abs/2011.10268},
keywords = {Software Engineering (cs.SE), FOS: Computer and information sciences, FOS: Computer and information sciences},
}
gumtree-spoon-ast-diff is heavily tested. The testing of AST tree differencing is quite interesting.
There are cases where the oracle is pretty clear, for instance for the deletion of a node.
// there is only one deletion at line 442
assertEquals(operations.size(), 1);
assertTrue(diff.containsOperation(operations, OperationKind.Delete, "Literal", "\"UTF-8\""));
assertEquals(442, result.changedNode().getPosition().getLine());
or for the addition of a single node
assertEquals(operations.size(), 1);
assertTrue(diff.containsOperation(operations, OperationKind.Insert, "Invocation", "append"));
However, with the presence of moves, the answer is less clear. For instance, an insert+delete instead of a move is correct, although not optimal. However, in this case, there are still definitive oracles: for instance, you are sure that the change happened within a certain node
// the change happened in System.out.println() at line 334
CtElement ancestor = result.commonAncestor();
assertTrue(ancestor instanceof CtInvocation);
assertEquals("println", ((CtInvocation)ancestor).getExecutable().getSimpleName());
assertEquals(344,ancestor.getPosition().getLine());
To conclude, for testing AST differencing, there is not always a unique and complete, it is a blend of assertions on:
Build your own version (mvn install
) or download the latest stable JAR on Maven.
To deploy a new version on Maven Central:
git branch -D deploy
(delete previous release)git checkout -b deploy
git commit -m release pom.xml
git push origin deploy -f
mvn -Prelease verify deploy:deploy
Copyright 2016 Matias Martinez
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
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http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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