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improve handling of custom handler CaseDefs in CatchThrowable #721

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Merged
merged 1 commit into from
Jul 10, 2025
Merged

improve handling of custom handler CaseDefs in CatchThrowable #721

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4 changes: 3 additions & 1 deletion analyzer/src/main/scala/com/avsystem/commons/analyzer/CatchThrowable.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,9 @@ class CatchThrowable(g: Global) extends AnalyzerRule(g, "catchThrowable", Level.
t.catches.foreach {
case CaseDef(Alternative(trees), _, _) => trees.foreach(checkTree)
case CaseDef(Bind(_, Alternative(trees)), _, _) => trees.foreach(checkTree)
case CaseDef(pat, _, _) => checkTree(pat)
// CaseDef generated from a custom handler has NoPosition
case cd@CaseDef(pat, _, _) if cd.pos != NoPosition => checkTree(pat)
case _ =>
}
case _ =>
}
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109 changes: 56 additions & 53 deletions analyzer/src/test/scala/com/avsystem/commons/analyzer/CatchThrowableTest.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -7,53 +7,47 @@ final class CatchThrowableTest extends AnyFunSuite with AnalyzerTest {
test("catching Throwable should be rejected") {
assertErrors(1,
scala"""
|def test(): Unit =
| try {
| println("test")
| } catch {
| case t: Throwable => println(t)
| }
|try {
| println("test")
|} catch {
| case t: Throwable => println(t)
|}
|""".stripMargin)
}

test("catching specific exceptions should be allowed") {
assertNoErrors(
scala"""
|def test(): Unit =
| try {
| println("test")
| } catch {
| case e: Exception => println(e)
| case e: RuntimeException => println(e)
| case e: IllegalArgumentException => println(e)
| }
|try {
| println("test")
|} catch {
| case e: Exception => println(e)
| case e: RuntimeException => println(e)
| case e: IllegalArgumentException => println(e)
|}
|""".stripMargin)
}

test("catching Throwable with other exceptions should be rejected") {
assertErrors(1,
scala"""
|def test(): Unit = {
| try {
| println("test")
| } catch {
| case e: IllegalArgumentException => println(e)
| case t: Throwable => println(t)
| }
|try {
| println("test")
|} catch {
| case e: IllegalArgumentException => println(e)
| case t: Throwable => println(t)
|}
|""".stripMargin)
}

test("catching Throwable in nested catch block should be rejected") {
assertErrors(1,
scala"""
|def test(): Unit = {
| try println("test")
|try println("test")
|catch {
| case e: Exception => try println("test")
| catch {
| case e: Exception => try println("test")
| catch {
| case e: Throwable => println(e)
| }
| case e: Throwable => println(e)
| }
|}
|""".stripMargin)
Expand All @@ -70,46 +64,55 @@ final class CatchThrowableTest extends AnyFunSuite with AnalyzerTest {
| case _ => None
| }
|}
|def test(): Unit = {
| try {
| println("test")
| } catch {
| case custom(t) => println(t)
| case NonFatal(t) => println(t)
| case scala.util.control.NonFatal(t) => println(t)
| }
|
|try {
| println("test")
|} catch {
| case custom(t) => println(t)
| case NonFatal(t) => println(t)
| case scala.util.control.NonFatal(t) => println(t)
|}
|""".stripMargin)
}

test("catching non-Throwable with pattern match should be allowed") {
assertNoErrors(
scala"""
|def test(): Unit = {
| try {
| println("test")
| } catch {
| case _: IndexOutOfBoundsException | _: NullPointerException => println("OK!")
| }
| try {
| println("test")
| } catch {
| case e@(_: IndexOutOfBoundsException | _: NullPointerException) => println("OK!")
| }
|try {
| println("test")
|} catch {
| case _: IndexOutOfBoundsException | _: NullPointerException => println("OK!")
|}
|""".stripMargin)
|try {
| println("test")
|} catch {
| case e@(_: IndexOutOfBoundsException | _: NullPointerException) => println("OK!")
|}
|""".stripMargin
)
}

test("catching Throwable with pattern match should be rejected") {
assertErrors(1,
scala"""
|def test(): Unit = {
| try {
| println("test")
| } catch {
| case _: IndexOutOfBoundsException | _: Throwable => println("Not OK!")
| }
|try {
| println("test")
|} catch {
| case _: IndexOutOfBoundsException | _: Throwable => println("Not OK!")
|}
|""".stripMargin)
}

test("catching Throwable using custom handler should be allowed") {
assertNoErrors(
scala"""
|object CustomHandler {
| def apply[T](): PartialFunction[Throwable, T] = ???
|}
|
|try {
| println("test")
|} catch CustomHandler()
|""".stripMargin)
}
}