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Add support for casts #710

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codecholeric opened this issue Oct 30, 2021 · 6 comments · May be fixed by #1081
Open

Add support for casts #710

codecholeric opened this issue Oct 30, 2021 · 6 comments · May be fixed by #1081
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enhancement good start to contributing help wanted topic:core

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@codecholeric
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At the moment casts without any further dependencies on the target type are not detected as dependencies. I.e.

SomeClass example(Object rawInput) {
  return (SomeClassImpl) rawInput; // should forbid dependencies on SomeClassImpl
}

Since there are no further dependencies on SomeClassImpl this would be missed. It does likely not cause a maintenance problem later, because the cast could at any time be weakened to (SomeClass) without any further compile or runtime issues, but still it would be nice to detect these things. Also to be able to access all casts that a class or method applies could be useful for other scenarios.

We could add this the following way:

  • extend Set<TypeCast> JavaCodeUnit.getCasts() (compare InstanceofCheck)
  • add the TypeCasts to JavaClass.directDependencies{From/To}Self

(open for discussion: What is the best name for the domain object? TypeCast, Cast, JavaCast, ClassCast, ...?)
@codecholeric codecholeric mentioned this issue Oct 30, 2021
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@Kaammill
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Is this issue open? If yes I would like to try to work on it.
I have a few questions about the task.
JavaClass.directDependencies{From/To}Self those methods are returning a set of Dependency objects. TypeCasts should be added to the dependency object or a new version of those methods is required like this: "getDirectDependenciesFromSelf(TypeCasts typeCasts)"?

@hankem
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hankem commented Feb 23, 2022

IMO we want both: (1) a specific method to ask domain objects for casts, and (2) register those as dependencies.

Random previous examples:

  • instanceof checks
  • .class references

@codecholeric
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@Kaammill and yes, the issue is up for grabs and we're always super happy about contributions 😃

Kaammill added a commit to Kaammill/ArchUnit that referenced this issue Mar 3, 2022
@Kaammill
init commit
bf97930 
Add support for casts
TNG#710

Signed-off-by: Kaammill  <>
@Kaammill Kaammill mentioned this issue Mar 3, 2022
Open
Kaammill added a commit to Kaammill/ArchUnit that referenced this issue Mar 8, 2022
@Kaammill
PR TNG#822 fix
3f9c75a 
task: TNG#710
@ratoaq2
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ratoaq2 commented Mar 9, 2023 •
edited

Some information about checkcast

The compiler might add some checkcast instructions:

  void foobar(java.lang.Object);
    Code:
       0: aload_1
       1: invokestatic  #29                 // Method com/foobar/SomeClass.of:(Ljava/lang/Object;)Lcom/foobar/SomeClass;
       4: ldc           #35                 // class java/lang/Boolean
       6: invokevirtual #37                 // Method com/foobar/SomeClass.someMethod:(Ljava/lang/Class;)Ljava/lang/Object;
       9: checkcast     #35                 // class java/lang/Boolean

What I noticed: if the previous instruction is invokevirtual or invokeinterface, the checkcast was generated by the compiler

@ratoaq2
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ratoaq2 commented Mar 9, 2023

Also bridge methods will have more compiler checkcast instructions

@ratoaq2
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ratoaq2 commented Mar 10, 2023

Detecting casts are also useful when working with polymorphism in hibernate, where instanceof and direct casts should not be used due to hibernate proxies.

Having this feature in archunit would also help in building rules for this case

ratoaq2 added a commit to ratoaq2/ArchUnit that referenced this issue Mar 12, 2023
@ratoaq2
support type cast detection TNG#710
bf83238 
Detect *checkcast* asm instructions as TypeCast (similar to
InstanceofCheck)
Implicit checkcast instructions generated by compiler due to method
invocations are ignored

Signed-off-by: Allan Jones <allan.jones@gmail.com>
@ratoaq2 ratoaq2 linked a pull request Mar 12, 2023 that will close this issue
Open
ratoaq2 added a commit to ratoaq2/ArchUnit that referenced this issue Mar 12, 2023
@ratoaq2
support type cast detection TNG#710
2730507 
Detect *checkcast* asm instructions as TypeCast (similar to
InstanceofCheck)
Implicit checkcast instructions generated by compiler due to method
invocations are ignored

Signed-off-by: Allan Jones <allan.jones@gmail.com>
ratoaq2 added a commit to ratoaq2/ArchUnit that referenced this issue Mar 12, 2023
@ratoaq2
support type cast detection TNG#710
bc7c038 
Detect checkcast asm instructions as TypeCast (similar to InstanceofCheck)
Implicit checkcast instructions generated by compiler due to method invocations are ignored

Resolves TNG#710

Signed-off-by: Allan Jones <allan.jones@gmail.com>
ratoaq2 added a commit to ratoaq2/ArchUnit that referenced this issue Mar 14, 2023
@ratoaq2
support type cast detection TNG#710
a4778c2 
Detect checkcast asm instructions as TypeCast (similar to InstanceofCheck)
Implicit checkcast instructions generated by compiler due to method invocations are ignored

Resolves TNG#710

Signed-off-by: Allan Jones <allan.jones@gmail.com>
ratoaq2 added a commit to ratoaq2/ArchUnit that referenced this issue Aug 12, 2023
@ratoaq2
support type cast detection TNG#710
9b3a512 
Detect checkcast asm instructions as TypeCast (similar to InstanceofCheck)
Implicit checkcast instructions generated by compiler due to method invocations are ignored

Resolves TNG#710

Signed-off-by: Allan Jones <allan.jones@gmail.com>
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support type cast detection ratoaq2/ArchUnit
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@codecholeric @hankem @ratoaq2 @Kaammill