Add support for complex short-circuiting in non-conditional flows #226
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sonalmahajan15
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Apr 3, 2024
This PR adds support for short-circuit `||` in non-conditional flows, thereby reducing false positives. For example, ``` return x == nil || *x == 1 ``` was reported as a false positive, since NilAway only analyzed `&&`. We apply logic similar to the handling of `&&`. Because this analysis resides in the recursion of the short-circuit expression, where we have limited context visibility, it makes it difficult to accurately analyze complex expressions. Therefore, with extending support for `||`, we had to trade-off some of the precision we previously had with only the `&&` support. However, we made this tough choice since empirically we observed that complex cases that we had to trade-off did not occur frequently enough, while simple `||` patterns were more prevalent. I have created issue #226 to keep a track of the comprehensive support that we plan to add in the future. [closes #92 ]
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NilAway can support prevalently found short-circuiting in non-conditional logical expressions. Examples of supported expressions are shown below (refer to nonconditional.go for detailed test cases).
Although not common, NilAway reports false negatives for complex short-circuit expressions, such as below.
Following are the ideas that can be used to extend support for the above cases:
if (a != nil || b == nil) && *a == 1 {}) are well-supported in NilAway. So, the idea here is to transform the non-conditional expression to a conditional expression in the pre-process phase. However, this would require the AST to be modified. We currently don't do this since drivers such as nogo create a shared AST between all linters. However, if we deeply copy the AST in NilAway, then this idea could be a viable approach.The text was updated successfully, but these errors were encountered: