| commit | 18c277f035c27dceccaf7efcc72212db4905419a | [log] [tgz] |
|---|---|---|
| author | Greg Estren <gregce@google.com> | Thu Apr 21 18:07:49 2016 +0000 |
| committer | Damien Martin-Guillerez <dmarting@google.com> | Fri Apr 22 11:48:53 2016 +0000 |
| tree | 3f6e357e7f8e6d8982503fd979fe077424a579e5 | |
| parent | df7b05fdef63caaa218bda6e9d8013b06c7f6f33 [diff] |
Make constraints and select() work well with each other.
This implements most of a design proposal that splits constraint checking
into two pieces: *static* checks, which apply the standard constraint checking
done today, and *refined* checks, which selectively prune environments based
on select paths and check that not every environment gets pruned out.
As a result of this change, dependencies like:
java_library(
name = "lib",
restricted_to = [":A", ":B"],
deps = select({
":config_a": [":depA"],
":config_b": [":depB"],
}))
java_library(
name = "depA",
restricted_to = [":A"])
java_library(
name = "depB",
restricted_to = [":B"])
are allowed.
Specifically, even though neither "depA" nor "depB" supports [":A", ":B"], the combination of the two does. So the select as a whole supports all environments declared in lib, even though only one of those environments actually gets chosen for a given build.
Refinement makes lib "match" the chosen path. So for "config_a" builds, lib's environment set is "refined" down to [":A"], meaning [":B"]-restricted rules cannot depend on it. Likewise, for "config_b" builds, lib's environment set is "refined" down to [":B"], meaning [":A"]-restricted rules cannot depend on it. This guarantees that the restrictions imposed by the chosen select path propagate faithfully up the dependency chain.
See new documentation in ConstraintSemantics.java for more details.
--
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