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= conflict-managers

*Tag:* conflict-managers

[ivysettings.conflict-managers]#Defines a list of link:../concept{outfilesuffix}#conflict[conflict managers] usable in Ivy.# Each conflict manager is identified by its name, given as an attribute.
The child tag used for the conflict manager must be equal to a name of a conflict manager type (either built-in or added with the `typedef` tag).

Here is a list of built-in conflict managers (which do not require anything in the settings file):


    * all +
     this conflict manager resolve conflicts by selecting all revisions. Also called the `NoConflictManager`, it doesn't evict any modules.

    * latest-time +
     this conflict manager selects only the `latest` revision, latest being defined as the latest in time. Note that latest in time is costly to compute, so prefer latest-revision if you can.

    * latest-revision +
     this conflict manager selects only the `latest` revision, latest being defined by a string comparison of revisions.

    * latest-compatible +
     this conflict manager selects the latest version in the conflicts which can result in a compatible set of dependencies. This means that in the end, this conflict manager does not allow any conflicts (similar to the strict conflict manager), except that it follows a best effort strategy to try to find a set of compatible modules (according to the version constraints)

    * strict +
     this conflict manager throws an exception (i.e. causes a build failure) whenever a conflict is found.

The two "latest" conflict managers also take into account the force attribute of the dependencies.
In fact, direct dependencies can declare a force attribute (see link:../ivyfile/dependency{outfilesuffix}[dependency]), which indicates that the revision given in the direct dependency should be preferred over indirect dependencies.

Here is a list of conflict manager types available, which can be used to define your own custom conflict managers:


    * latest-cm +
    The latest conflict manager uses a latest strategy to select the latest revision among several ones. Both `latest-time` and `latest-revision` conflict managers are based on this conflict manager type. It takes `latest` as attribute to define which latest strategy should be used. Example:

[source, xml]
----
<latest-cm name="mylatest-conflict-manager" latest="my-latest-strategy"/>
----


    * compatible-cm +
    The latest compatible conflict manager uses a latest strategy to select the latest revision among several ones. It takes `latest` as an attribute to define which latest strategy should be used. Example:

[source, xml]
----
<compatible-cm name="my-latest-compatible-conflict-manager" latest="my-latest-strategy"/>
----


    * regexp-cm +
    This conflict manager is based on a regular expression and throws an exception (i.e. causes a build failure) when a conflict is found with versions with different matching group. For instance, if a conflict is found between 1.2.x and 1.3.y it will throw an exception if the regular expression is `(.*)\.\d`, because the matching group will match different strings (1.2 and 1.3). 1.2.1 and 1.2.2 won't throw an exception with the same regular expression. The regular expression is set using the `regexp` attribute. A `ignoreNonMatching` attribute can also be set to simply warn when a version is found which does not match the regular expression, instead of throwing an exception.



== Child elements


[options="header"]
|=======
|Element|Description|Cardinality
|any conflict manager|adds a conflict manager to the list of available conflict managers|0..n
|=======
