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Fuzzy patching does not account for earlier changes in line count #237
Description
applyFuzzy(source, 0) can fail on the unchanged source after an earlier change reduces the line count:
import com.github.difflib.DiffUtils;
import com.github.difflib.patch.Patch;
import java.util.Arrays;
import java.util.List;
public class Reproduce {
public static void main(String[] args) throws Exception {
List<String> source=Arrays.asList("a","b","c","d","e");
List<String> target=Arrays.asList("x","d","y");
Patch<String> patch=DiffUtils.diff(source,target);
System.out.println(patch.getDeltas());
System.out.println("exact="+patch.applyTo(source));
System.out.println("fuzzy="+patch.applyFuzzy(source,0));
}
}applyTo returns [x, d, y]. applyFuzzy throws IndexOutOfBoundsException with 4.17 and PatchFailedException with current master instead of returning the same result.
An expanding earlier change can also cause a later delta to modify a newly inserted matching line. lastPatchDelta only records the found position; it needs to include the difference between the target and source chunk sizes as well.
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