Circular dependencies with export CDIST_ORDER_DEPENDENCY=1 #99

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opened 2021-11-20 13:23:53 +00:00 by ungleich-gitea · 2 comments

Created by: darko-poljak

In mailing list the following case was reported as not working, resulting in circular dependency.

Init manifest

__foo

__foo type manifest:

export CDIST_ORDER_DEPENDENCY=1

__group ...
__user ...

Error

The requirements of the following objects could
not be resolved:
__user/... requires:
         __group/...
__user/... autorequires:

__group/... requires:
         __foo/...
__group/... autorequires:

__foo/... requires:

__foo/... autorequires:
         __user/... 

__user/... requires:
__group/...
is the result of injecting last created type requirement
__group/... requires:
__foo/...
is the result of injecting last created type requirement
__foo/... autorequires:
__user/...
is the result of autorequirement.

foo autorequires group is not set since group requires foo was injected.

*Created by: darko-poljak* In mailing list the following case was reported as not working, resulting in circular dependency. Init manifest ``` __foo ``` __foo type manifest: ``` export CDIST_ORDER_DEPENDENCY=1 __group ... __user ... ``` Error ``` The requirements of the following objects could not be resolved: __user/... requires: __group/... __user/... autorequires: __group/... requires: __foo/... __group/... autorequires: __foo/... requires: __foo/... autorequires: __user/... ``` __user/... requires: __group/... is the result of injecting last created type requirement __group/... requires: __foo/... is the result of injecting last created type requirement __foo/... autorequires: __user/... is the result of autorequirement. foo autorequires group is not set since group requires foo was injected.
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Created by: darko-poljak

@telmich I will try to clarify the case better.

Let we have the following init manifest:

__foo

and foo type manifest:

export CDIST_ORDER_DEPENDENCY=1

__group ...
__user ...

So this means that we want dependency in type's manifest based on the order of types.
Here we want that __user type requires __group type.

What cdist determines is that

__group/... requires: __foo/...
__user/... requires: __group/...
__foo/... requires:  __user/...

So, __user requires __group, which requires __foo, which requires __user, and we have circle here.

How we came to that dependency tree?

  1. __foo type should depend on all types it uses in its manifest.
    When __foo type is executed, first __group type is executed.
  2. cdist sess that CDIST_ORDER_DEPENDENCY is defined.
    It looks for the previous type created. It finds __foo type and injects it as a requirement.
    And now we have __group/... requires: __foo/....
  3. Next step is auto requirement. cdist tries to define that __foo auto requires __gorup,
    but it sees that __group already requires __foo so it skips this.
  4. Next __user type is executed.
  5. cdist sess that CDIST_ORDER_DEPENDENCY is defined.
    It looks for the previous type created. It finds __group type and injects it as a requirement.
    And now we have __user/... requires: __group/....
  6. Next step is auto requirement. cdist tries to define that __foo auto requires __user,
    it sees that there is no __user requires __foo so it defines:
    __foo/... autorequires:__user/....

In the end we have this:

__group/... requires: __foo/...
__user/... requires: __group/...
__foo/... requires:  __user/...

And this is wrong!

The wrong step is in 2.. cdist should not inject requirement of type which manifest is being executed for a type in type's manifest. In the above case, requirement of __foo for type __group should not be injected!
Note that when CDIST_ORDER_DEPENDENCY in used only in init manifest, this does not happen because for init manifest, when first type is executed, previous type created is None.

*Created by: darko-poljak* @telmich I will try to clarify the case better. Let we have the following init manifest: ``` __foo ``` and foo type manifest: ``` export CDIST_ORDER_DEPENDENCY=1 __group ... __user ... ``` So this means that we want dependency in type's manifest based on the order of types. Here we want that `__user` type requires `__group` type. What cdist determines is that ``` __group/... requires: __foo/... __user/... requires: __group/... __foo/... requires: __user/... ``` So, `__user` requires `__group`, which requires `__foo`, which requires `__user`, and we have circle here. How we came to that dependency tree? 1. `__foo` type should depend on all types it uses in its manifest. When `__foo` type is executed, first `__group` type is executed. 2. cdist sess that `CDIST_ORDER_DEPENDENCY` is defined. It looks for the previous type created. It finds `__foo` type and injects it as a requirement. And now we have `__group/... requires: __foo/...`. 3. Next step is auto requirement. cdist tries to define that `__foo` auto requires `__gorup`, but it sees that `__group` already requires `__foo` so it skips this. 4. Next `__user` type is executed. 5. cdist sess that `CDIST_ORDER_DEPENDENCY` is defined. It looks for the previous type created. It finds `__group` type and injects it as a requirement. And now we have `__user/... requires: __group/...`. 6. Next step is auto requirement. cdist tries to define that `__foo` auto requires `__user`, it sees that there is no `__user` requires `__foo` so it defines: `__foo/... autorequires:__user/...`. In the end we have this: ``` __group/... requires: __foo/... __user/... requires: __group/... __foo/... requires: __user/... ``` And this is wrong! The wrong step is in **2.**. cdist **should not** inject requirement of type which manifest is being executed for a type in type's manifest. In the above case, requirement of `__foo` for type `__group` should not be injected! Note that when `CDIST_ORDER_DEPENDENCY` in used only in init manifest, this does not happen because for init manifest, when first type is executed, previous type created is **None**.
Author
Owner

Created by: darko-poljak

@telmich @asteven
The wrong part here is
__group/... requires:
__foo/...
injection.

When CDIST_ORDER_REQUIREMENT is set, if last created type is object whose type manifest is
currently being executed, then such requirement should not be injected.

PR follows.

*Created by: darko-poljak* @telmich @asteven The wrong part here is __group/... requires: __foo/... injection. When CDIST_ORDER_REQUIREMENT is set, if last created type is object whose type manifest is currently being executed, then such requirement should not be injected. PR follows.
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Reference: ungleich-public/cdist#99
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