Don't always provide transitive dependencies' analysis files to ZincRunner

They aren't used if Zinc persistence is disabled. They also contain
hashes of sources, which effectively makes `ijar` useless, since a
target will be always be recompiled if its transitive dependencies
were changed, regardless of whether their ijars changed.

Author: Jaden Peterson

rules/private/phases/phase_zinc_compile.bzl

@@ -38,7 +38,9 @@ def phase_zinc_compile(ctx, g):
     common_scalacopts = toolchain.scala_configuration.global_scalacopts + ctx.attr.scalacopts
 
     args = ctx.actions.args()
-    args.add_all(depset(transitive = [zinc.deps for zinc in zincs]), map_each = _compile_analysis)
+    if toolchain.zinc_configuration.incremental:
+        args.add_all(depset(transitive = [zinc.deps for zinc in zincs]), map_each = _compile_analysis)
+
     args.add("--compiler_bridge", toolchain.zinc_configuration.compiler_bridge)
     args.add_all("--compiler_classpath", g.classpaths.compiler)
     args.add_all("--classpath", g.classpaths.compile)
@@ -69,7 +71,7 @@ def phase_zinc_compile(ctx, g):
             g.classpaths.plugin,
             g.classpaths.compile,
             g.classpaths.compiler,
-        ] + [zinc.deps_files for zinc in zincs],
+        ] + ([zinc.deps_files for zinc in zincs] if toolchain.zinc_configuration.incremental else []),
     )
 
     outputs = [

tests/ijar/BUILD.bazel

@@ -0,0 +1,20 @@
+load("@rules_scala_annex//rules:scala.bzl", "scala_library")
+
+scala_library(
+    name = "dependency",
+    srcs = [
+        "Dependency.scala",
+        "DependencyCacheInvalidation.scala",
+    ],
+    scala_toolchain_name = "test_zinc_2_13",
+)
+
+scala_library(
+    name = "dependent",
+    srcs = [
+        "Dependent.scala",
+        "DependentCacheInvalidation.scala",
+    ],
+    scala_toolchain_name = "test_zinc_2_13",
+    deps = [":dependency"],
+)

tests/ijar/Dependency.scala

@@ -0,0 +1,7 @@
+package anx.ijar
+
+object Dependency {
+  def main(args: Array[String]): Unit = {
+    println("Hello, world!")
+  }
+}

tests/ijar/DependencyCacheInvalidation.scala

@@ -0,0 +1,5 @@
+package anx.ijar
+
+object Dependent {
+  def main(args: Array[String]): Unit = Dependency.main(args)
+}

tests/ijar/Dependent.scala

@@ -0,0 +1,32 @@
+#!/bin/bash -e
+. "$(dirname "$0")"/../common.sh
+
+invalidate_dependency_cache() {
+  echo "// $(cat /proc/sys/kernel/random/uuid)" > DependencyCacheInvalidation.scala
+}
+
+invalidate_dependent_cache() {
+  echo "// $(cat /proc/sys/kernel/random/uuid)" > DependentCacheInvalidation.scala
+}
+
+test_actions_executed() {
+  scalacompile_runs="$(
+    bazel build --color no --subcommands "$1" |& \
+      grep '^SUBCOMMAND: # //ijar:.* \[.*, mnemonic: ScalaCompile\]$' | \
+      wc -l
+  )"
+
+  if [ "$scalacompile_runs" -ne "$2" ]; then
+    echo "Expected 1 \`ScalaCompile\` action to be executed, but got $scalacompile_runs"
+    exit 1
+  fi
+}
+
+trap ": > DependencyCacheInvalidation.scala; : > DependentCacheInvalidation.scala" EXIT
+
+invalidate_dependency_cache
+invalidate_dependent_cache
+test_actions_executed //ijar:dependent 2
+
+invalidate_dependency_cache
+test_actions_executed //ijar:dependent 1