final phase is inlined (bazelbuild#947)

all phases are equal
DefaultInfo is returned by a default_info phase
Other external providers are passed by their respective phases

docs/customizable_phase.md

@@ -128,14 +128,14 @@ Currently phase architecture is used by 7 rules:
  - scala_junit_test
  - scala_repl
 
-In each of the rule implementation, it calls `run_phases` and returns the information from `phase_final`, which groups the final returns of the rule. To prevent consumers from accidently removing `phase_final` from the list, we make it a non-customizable phase.
+If you need to expose providers to downstream targets you need to return an array of providers from your phase under the `external_providers` attribute.
+
+In each of the rule implementations, it calls `run_phases` and returns an accumulated `external_providers` array declared by the phases.
 
 To make a new phase, you have to define a new `phase_<PHASE_NAME>.bzl` in `scala/private/phases/`. Function definition should have 2 arguments, `ctx` and `p`. You may expose the information for later phases by returning a `struct`. In some phases, there are multiple phase functions since different rules may take slightly different input arguemnts. You may want to re-expose the phase definition in `scala/private/phases/phases.bzl`, so it's more convenient to access in rule files.
 
 In the rule implementations, put your new phase in `builtin_customizable_phases` list. The phases are executed sequentially, the order matters if the new phase depends on previous phases.
 
-If you are making new return fields of the rule, remember to modify `phase_final`.
-
 ### Phase naming convention
 Files in `scala/private/phases/`
  - `phase_<PHASE_NAME>.bzl`: phase definition file

scala/private/phases/api.bzl

@@ -41,7 +41,7 @@ def _adjust_phases(phases, adjustments):
     return phases
 
 # Execute phases
-def run_phases(ctx, builtin_customizable_phases, fixed_phase):
+def run_phases(ctx, builtin_customizable_phases):
     # Loading custom phases
     # Phases must be passed in by provider
     phase_providers = [
@@ -64,7 +64,7 @@ def run_phases(ctx, builtin_customizable_phases, fixed_phase):
     global_provider = {}
     current_provider = struct(**global_provider)
     acculmulated_external_providers = []
-    for (name, function) in adjusted_phases + [fixed_phase]:
+    for (name, function) in adjusted_phases:
         # Run a phase
         new_provider = function(ctx, current_provider)
 
@@ -77,7 +77,7 @@ def run_phases(ctx, builtin_customizable_phases, fixed_phase):
             current_provider = struct(**global_provider)
 
     # The final return of rules implementation
-    return acculmulated_external_providers + current_provider.final
+    return acculmulated_external_providers
 
 # A method to pass in phase provider
 def extras_phases(extras):

scala/private/phases/phase_collect_jars.bzl

@@ -108,6 +108,7 @@ def _phase_collect_jars(
         transitive_compile_jars = transitive_compile_jars,
         transitive_runtime_jars = transitive_rjars,
         deps_providers = deps_providers,
+        external_providers = [jars2labels],
     )
 
 def _collect_runtime_jars(dep_targets):

scala/private/phases/phase_compile.bzl

@@ -170,6 +170,7 @@ def _phase_compile(
         java_jar = out.java_jar,
         source_jars = _pack_source_jars(ctx) + out.source_jars,
         merged_provider = out.merged_provider,
+        external_providers = [out.merged_provider] + out.coverage.providers,
     )
 
 def _compile_or_empty(

scala/private/phases/phase_default_info.bzl

@@ -0,0 +1,36 @@
+#
+# PHASE: default_info
+#
+# DOCUMENT THIS
+#
+def phase_binary_default_info(ctx, p):
+    return struct(
+        external_providers = [
+            DefaultInfo(
+                executable = p.declare_executable,
+                files = depset([p.declare_executable] + p.compile.full_jars),
+                runfiles = p.runfiles.runfiles,
+            ),
+        ],
+    )
+
+def phase_library_default_info(ctx, p):
+    return struct(
+        external_providers = [
+            DefaultInfo(
+                files = depset(p.compile.full_jars),
+                runfiles = p.runfiles.runfiles,
+            ),
+        ],
+    )
+
+def phase_scalatest_default_info(ctx, p):
+    return struct(
+        external_providers = [
+            DefaultInfo(
+                executable = p.declare_executable,
+                files = depset([p.declare_executable] + p.compile.full_jars),
+                runfiles = ctx.runfiles(p.coverage_runfiles.coverage_runfiles, transitive_files = p.runfiles.runfiles.files),
+            ),
+        ],
+    )

scala/private/phases/phases.bzl

@@ -46,10 +46,10 @@ load(
     _phase_scalatest_runfiles = "phase_scalatest_runfiles",
 )
 load(
-    "@io_bazel_rules_scala//scala/private:phases/phase_final.bzl",
-    _phase_binary_final = "phase_binary_final",
-    _phase_library_final = "phase_library_final",
-    _phase_scalatest_final = "phase_scalatest_final",
+    "@io_bazel_rules_scala//scala/private:phases/phase_default_info.bzl",
+    _phase_binary_default_info = "phase_binary_default_info",
+    _phase_library_default_info = "phase_library_default_info",
+    _phase_scalatest_default_info = "phase_scalatest_default_info",
 )
 load("@io_bazel_rules_scala//scala/private:phases/phase_scalac_provider.bzl", _phase_scalac_provider = "phase_scalac_provider")
 load("@io_bazel_rules_scala//scala/private:phases/phase_write_manifest.bzl", _phase_write_manifest = "phase_write_manifest")
@@ -125,7 +125,7 @@ phase_library_runfiles = _phase_library_runfiles
 phase_scalatest_runfiles = _phase_scalatest_runfiles
 phase_common_runfiles = _phase_common_runfiles
 
-# final
-phase_binary_final = _phase_binary_final
-phase_library_final = _phase_library_final
-phase_scalatest_final = _phase_scalatest_final
+# default_info
+phase_binary_default_info = _phase_binary_default_info
+phase_library_default_info = _phase_library_default_info
+phase_scalatest_default_info = _phase_scalatest_default_info

scala/private/rules/scala_binary.bzl

@@ -13,7 +13,7 @@ load(
     "@io_bazel_rules_scala//scala/private:phases/phases.bzl",
     "extras_phases",
     "phase_binary_compile",
-    "phase_binary_final",
+    "phase_binary_default_info",
     "phase_common_collect_jars",
     "phase_common_java_wrapper",
     "phase_common_runfiles",
@@ -42,9 +42,8 @@ def _scala_binary_impl(ctx):
             ("merge_jars", phase_merge_jars),
             ("runfiles", phase_common_runfiles),
             ("write_executable", phase_common_write_executable),
+            ("default_info", phase_binary_default_info),
         ],
-        # fixed phase
-        ("final", phase_binary_final),
     )
 
 _scala_binary_attrs = {

scala/private/rules/scala_junit_test.bzl

@@ -11,7 +11,7 @@ load("@io_bazel_rules_scala//scala/private:common_outputs.bzl", "common_outputs"
 load(
     "@io_bazel_rules_scala//scala/private:phases/phases.bzl",
     "extras_phases",
-    "phase_binary_final",
+    "phase_binary_default_info",
     "phase_common_java_wrapper",
     "phase_common_runfiles",
     "phase_declare_executable",
@@ -47,9 +47,8 @@ def _scala_junit_test_impl(ctx):
             ("runfiles", phase_common_runfiles),
             ("jvm_flags", phase_jvm_flags),
             ("write_executable", phase_junit_test_write_executable),
+            ("default_info", phase_binary_default_info),
         ],
-        # fixed phase
-        ("final", phase_binary_final),
     )
 
 _scala_junit_test_attrs = {

scala/private/rules/scala_library.bzl

@@ -22,7 +22,7 @@ load(
     "phase_collect_srcjars",
     "phase_common_collect_jars",
     "phase_library_compile",
-    "phase_library_final",
+    "phase_library_default_info",
     "phase_library_for_plugin_bootstrapping_collect_jars",
     "phase_library_for_plugin_bootstrapping_compile",
     "phase_library_runfiles",
@@ -66,9 +66,8 @@ def _scala_library_impl(ctx):
             ("merge_jars", phase_merge_jars),
             ("runfiles", phase_library_runfiles),
             ("collect_exports_jars", phase_collect_exports_jars),
+            ("default_info", phase_library_default_info),
         ],
-        # fixed phase
-        ("final", phase_library_final),
     )
 
 _scala_library_attrs = {}
@@ -143,9 +142,8 @@ def _scala_library_for_plugin_bootstrapping_impl(ctx):
             ("merge_jars", phase_merge_jars),
             ("runfiles", phase_library_runfiles),
             ("collect_exports_jars", phase_collect_exports_jars),
+            ("default_info", phase_library_default_info),
         ],
-        # fixed phase
-        ("final", phase_library_final),
     )
 
 # the scala compiler plugin used for dependency analysis is compiled using `scala_library`.
@@ -199,9 +197,8 @@ def _scala_macro_library_impl(ctx):
             ("merge_jars", phase_merge_jars),
             ("runfiles", phase_library_runfiles),
             ("collect_exports_jars", phase_collect_exports_jars),
+            ("default_info", phase_library_default_info),
         ],
-        # fixed phase
-        ("final", phase_library_final),
     )
 
 _scala_macro_library_attrs = {

scala/private/rules/scala_repl.bzl

@@ -12,7 +12,7 @@ load("@io_bazel_rules_scala//scala/private:common_outputs.bzl", "common_outputs"
 load(
     "@io_bazel_rules_scala//scala/private:phases/phases.bzl",
     "extras_phases",
-    "phase_binary_final",
+    "phase_binary_default_info",
     "phase_common_runfiles",
     "phase_declare_executable",
     "phase_merge_jars",
@@ -43,9 +43,8 @@ def _scala_repl_impl(ctx):
             ("merge_jars", phase_merge_jars),
             ("runfiles", phase_common_runfiles),
             ("write_executable", phase_repl_write_executable),
+            ("default_info", phase_binary_default_info),
         ],
-        # fixed phase
-        ("final", phase_binary_final),
     )
 
 _scala_repl_attrs = {

scala/private/rules/scala_test.bzl

@@ -19,7 +19,7 @@ load(
     "phase_scalac_provider",
     "phase_scalatest_collect_jars",
     "phase_scalatest_compile",
-    "phase_scalatest_final",
+    "phase_scalatest_default_info",
     "phase_scalatest_runfiles",
     "phase_scalatest_write_executable",
     "phase_unused_deps_checker",
@@ -44,9 +44,8 @@ def _scala_test_impl(ctx):
             ("runfiles", phase_scalatest_runfiles),
             ("coverage_runfiles", phase_coverage_runfiles),
             ("write_executable", phase_scalatest_write_executable),
+            ("default_info", phase_scalatest_default_info),
         ],
-        # fixed phase
-        ("final", phase_scalatest_final),
     )
 
 _scala_test_attrs = {