René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Support Kotlin null safety","articleBody":"**Description**\r\n\r\nWe have to properly handle Kotlin nullable and not-nullable types to produce correct tests:\r\n\r\n1. We shouldn't generate models in which value of not-nullable type is `null`\r\n2. We should put `?.` and `!!` in generated files where it is needed.\r\n3. We should properly handle possibly-null values returned by java code.\r\n\r\nThere were some attempts to support this, but this is only partially supported currently.\r\n\r\n**To Reproduce**\r\n\r\nThere are many cases where behavior is incorrect. For example, launch action on the following class:\r\n\r\n```Kotlin\r\nclass NullabilityIssuesExample(var x: Int) {\r\n    fun copyWithX(new_x: Int?): NullabilityIssuesExample? {\r\n        if (new_x == null)\r\n            return null\r\n        return NullabilityIssuesExample(x + new_x)\r\n    }\r\n}\r\n```\r\n\r\n**Expected behavior**\r\n\r\nCorrect tests are generated.\r\n\r\n**Actual behavior**\r\n\r\nAmong others, the following test is generated:\r\n\r\n```Kotlin\r\nfun testCopyWithX2() {\r\n    val nullabilityIssuesExample = NullabilityIssuesExample(-255)\r\n    val new_x = -255\r\n    \r\n    val actual = nullabilityIssuesExample.copyWithX(new_x)\r\n    \r\n    val expected = NullabilityIssuesExample(0)\r\n    expected.x = -510\r\n    val expectedX = expected.x\r\n    val actualX = actual.x\r\n    assertEquals(expectedX, actualX)   \r\n}\r\n```\r\n\r\n**Additional context**\r\n\r\nThis is an old big issue, which may be solved step by step.\r\n","author":{"url":"https://github.com/volivan239","@type":"Person","name":"volivan239"},"datePublished":"2022-10-28T13:39:32.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/1257/UTBotJava/issues/1257"}