Automated software program repair

One or more non-transitory computer-readable storage media configured to store instructions that, in response to being executed, cause a system to perform operations, the operations comprising:

• generating a first abstract syntax tree with respect to a first iteration of first source code of a first software program, the first iteration excluding a particular change in a particular portion of the first source code;
• generating a second abstract syntax tree with respect to a second iteration of the first source code, the second iteration including the particular change in the particular portion, the particular change including a plurality of modifications made with respect to the particular portion of the first source code;
• identifying a first sub-tree of the first abstract syntax tree that corresponds to the particular portion with respect to the first iteration of the first source code;
• identifying a plurality of second sub-trees of the second abstract syntax tree that correspond to the particular portion with respect to the second iteration of the first source code;
• generating a first textual representation of the first sub-tree;
• generating a plurality of second textual representations in which a respective second textual representation is generated for each of the second sub-trees;
• performing a difference determination between the first textual representation and each of the second textual representations;
• identifying, from the second textual representations based on the difference determination, one or more differing textual representations that differ from the first textual representation, each differing textual representation corresponding to one or more respective modifications of the particular change;
• determining a smallest-sized set of the differing textual representations that corresponds to a same particular event as the particular change, the particular event occurring with respect to the first source code from the first iteration to the second iteration;
• identifying, as secondary textual representations, the differing textual representations that are outside of the smallest-sized set, the secondary textual representations corresponding to secondary modifications of the plurality of modifications;
• identifying, as secondary trees, the second sub-trees that correspond to the secondary textual representations;
• modifying the second abstract syntax tree by removing the secondary trees from the second abstract syntax tree;
• obtaining a third iteration of the first source code by regenerating the first source code based on the modified second abstract syntax tree;
• and
• performing repair operations with respect to one or more of the first source code and second source code of a second software program based on the third iteration of the first source code.

A system comprising:

• one or more computer-readable storage media configured to store instructions;
• and
• one or more processors communicatively coupled to the one or more computer- readable storage media and configured to, in response to execution of the instructions, cause the system to perform operations, the operations comprising:
• generating a first abstract syntax tree with respect to a first iteration of first source code of a first software program, the first iteration excluding a particular change in a particular portion of the first source code;
• generating a second abstract syntax tree with respect to a second iteration of the first source code, the second iteration including the particular change in the particular portion, the particular change including a plurality of modifications made with respect to the particular portion of the first source code;
• identifying a first sub-tree of the first abstract syntax tree that corresponds to the particular portion with respect to the first iteration of the first source code;
• identifying a plurality of second sub-trees of the second abstract syntax tree that correspond to the particular portion with respect to the second iteration of the first source code;
• generating a first textual representation of the first sub-tree;
• generating a plurality of second textual representations in which a respective second textual representation is generated for each of the second sub- trees;
• performing a difference determination between the first textual representation and each of the second textual representations;
• identifying, from the second textual representations based on the difference determination, one or more differing textual representations that differ from the first textual representation, each differing textual representation corresponding to one or more respective modifications of the particular change;
• determining a smallest-sized set of the differing textual representations that corresponds to a same particular event as the particular change, the particular event occurring with respect to the first source code from the first iteration to the second iteration;
• identifying, as secondary textual representations, the differing textual representations that are outside of the smallest-sized set, the secondary textual representations corresponding to secondary modifications of the plurality of modifications;
• identifying, as secondary trees, the second sub-trees that correspond to the secondary textual representations;
• modifying the second abstract syntax tree by removing the secondary trees from the second abstract syntax tree;
• obtaining a third iteration of the first source code by regenerating the first source code based on the modified second abstract syntax tree;
• and
• performing repair operations with respect to one or more of the first source code and second source code of a second software program based on the third iteration of the first source code.