Usage of Gradle option "--parallel" should be safe

Gradle should not execute several "yarn install" in parallel,
because Yarn doesn't support concurrent access to its global cache.

"task1.mustRunAfter(task2)" ordering has an effect only when both
tasks are scheduled for execution, however currently task
":private:docs:yarn" is not executed during execution of "gradle build".
Therefore "mustRunAfter" should be established between all pairs of
"yarn install" tasks to define their total order and to prevent their
concurrent execution even in case when one or more of these tasks not
scheduled.

1 files changed, 7 insertions, 2 deletions

diff --git a/build.gradle b/build.gradle
index a2b1fd54c46..9ce55594e38 100644
--- a/build.gradle
+++ b/build.gradle
@@ -422,9 +422,14 @@ subprojects {
 // Yarn doesn't support concurrent access to its global cache,
 // i.e. parallel execution of several "yarn install" tasks,
 // since these tasks are independent, we can establish arbitrary total order
-// to prevent their concurrent execution:
+// to prevent their concurrent execution.
+// Note that "task1.mustRunAfter(task2)" ordering has an effect only when both
+// tasks are scheduled for execution, therefore should be established between
+// all pairs of "yarn install" tasks to define their total order and to prevent
+// their concurrent execution even in case when one or more of these tasks not
+// scheduled.
 def yarnInstallTasks = allprojects.findResults { it -> it.tasks.findByName('yarn') }
-yarnInstallTasks.eachWithIndex { it, i -> if (i > 0) it.mustRunAfter(yarnInstallTasks.get(i - 1)) }
+yarnInstallTasks.drop(1).eachWithIndex { it, i -> it.mustRunAfter(yarnInstallTasks[0..i]) }
 
 
 artifactory {