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Diffstat (limited to 'doc/concepts/rules.md')
| -rw-r--r-- | doc/concepts/rules.md | 13 |
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diff --git a/doc/concepts/rules.md b/doc/concepts/rules.md index a9db5705..2e09cb81 100644 --- a/doc/concepts/rules.md +++ b/doc/concepts/rules.md @@ -149,6 +149,19 @@ has to be a map of artifacts. The result is a single tree artifact formed from the input map. It is an error if the map cannot be transformed into a tree (e.g., due to staging conflicts). +### `TREE_OVERLAY` and `DISJOINT_TREE_OVERLAY` + +The `TREE_OVERLAY` and `DISJOINT_TREE_OVERLAY` functions take a +single (evaluated) argument `$1` which has to be a list of maps +of artifacts. Each entry in the list is transformed into a single +tree artifact formed from that map and it is an error if the map +cannot be transformed into a tree (e.g., due to a staging conflict). +The result is a single tree artifact defined as the overlay of the +specified trees in that order (latest wins on each path after build +evaluation); in the case of `DISJOINT_TREE_OVERLAY` it is a build +error if a non-trivial conflict arises when computing the overlay +in the build phase. + #### `ACTION` Actions are a way to define new artifacts from (zero or more) |