Get files with extension (bazelbuild#979)

* Get files helper function

* Remove extra computation

* Move extension to shared file

* Move functions to paths.bzl

scala/private/paths.bzl

@@ -0,0 +1,12 @@
+java_extension = ".java"
+
+scala_extension = ".scala"
+
+srcjar_extension = ".srcjar"
+
+def get_files_with_extension(ctx, extension):
+    return [
+        f
+        for f in ctx.files.srcs
+        if f.basename.endswith(extension)
+    ]

scala/private/phases/phase_compile.bzl

@@ -9,19 +9,20 @@ load(
     "@io_bazel_rules_scala//scala/private:coverage_replacements_provider.bzl",
     _coverage_replacements_provider = "coverage_replacements_provider",
 )
+load(
+    "@io_bazel_rules_scala//scala/private:paths.bzl",
+    _get_files_with_extension = "get_files_with_extension",
+    _java_extension = "java_extension",
+    _scala_extension = "scala_extension",
+    _srcjar_extension = "srcjar_extension",
+)
 load(
     "@io_bazel_rules_scala//scala/private:rule_impls.bzl",
     _compile_scala = "compile_scala",
     _expand_location = "expand_location",
 )
 load(":resources.bzl", _resource_paths = "paths")
 
-_java_extension = ".java"
-
-_scala_extension = ".scala"
-
-_srcjar_extension = ".srcjar"
-
 _empty_coverage_struct = struct(
     external = struct(
         replacements = {},
@@ -197,29 +198,17 @@ def _compile_or_empty(
             merged_provider = scala_compilation_provider,
         )
     else:
-        in_srcjars = [
-            f
-            for f in ctx.files.srcs
-            if f.basename.endswith(_srcjar_extension)
-        ]
+        java_srcs = _get_files_with_extension(ctx, _java_extension)
+        scala_srcs = _get_files_with_extension(ctx, _scala_extension)
+        in_srcjars = _get_files_with_extension(ctx, _srcjar_extension)
         all_srcjars = depset(in_srcjars, transitive = [srcjars])
 
-        java_srcs = [
-            f
-            for f in ctx.files.srcs
-            if f.basename.endswith(_java_extension)
-        ]
-
         # We are not able to verify whether dependencies are used when compiling java sources
         # Thus we disable unused dependency checking when java sources are found
         if len(java_srcs) != 0:
             unused_dependency_checker_mode = "off"
 
-        sources = [
-            f
-            for f in ctx.files.srcs
-            if f.basename.endswith(_scala_extension)
-        ] + java_srcs
+        sources = scala_srcs + java_srcs
         _compile_scala(
             ctx,
             ctx.label,
@@ -258,7 +247,7 @@ def _compile_or_empty(
             #  so set ijar == jar
             ijar = ctx.outputs.jar
 
-        source_jar = _pack_source_jar(ctx)
+        source_jar = _pack_source_jar(ctx, scala_srcs, in_srcjars)
         scala_compilation_provider = _create_scala_compilation_provider(ctx, ijar, source_jar, deps_providers)
 
         # compile the java now
@@ -339,31 +328,16 @@ def _create_scala_compilation_provider(ctx, ijar, source_jar, deps_providers):
         runtime_deps = runtime_deps,
     )
 
-def _pack_source_jar(ctx):
-    # collect .scala sources and pack a source jar for Scala
-    scala_sources = [
-        f
-        for f in ctx.files.srcs
-        if f.basename.endswith(_scala_extension)
-    ]
-
-    # collect .srcjar files and pack them with the scala sources
-    bundled_source_jars = [
-        f
-        for f in ctx.files.srcs
-        if f.basename.endswith(_srcjar_extension)
-    ]
-    scala_source_jar = java_common.pack_sources(
+def _pack_source_jar(ctx, scala_srcs, in_srcjars):
+    return java_common.pack_sources(
         ctx.actions,
         output_jar = ctx.outputs.jar,
-        sources = scala_sources,
-        source_jars = bundled_source_jars,
+        sources = scala_srcs,
+        source_jars = in_srcjars,
         java_toolchain = find_java_toolchain(ctx, ctx.attr._java_toolchain),
         host_javabase = find_java_runtime_toolchain(ctx, ctx.attr._host_javabase),
     )
 
-    return scala_source_jar
-
 def _jacoco_offline_instrument(ctx, input_jar):
     if not ctx.configuration.coverage_enabled or not hasattr(ctx.attr, "_code_coverage_instrumentation_worker"):
         return _empty_coverage_struct

scala/private/phases/phase_scalafmt.bzl

@@ -3,6 +3,11 @@
 #
 # Outputs to format the scala files when it is explicitly specified
 #
+load(
+    "@io_bazel_rules_scala//scala/private:paths.bzl",
+    _scala_extension = "scala_extension",
+)
+
 def phase_scalafmt(ctx, p):
     if ctx.attr.format:
         manifest, files = _build_format(ctx)
@@ -17,7 +22,7 @@ def _build_format(ctx):
     manifest_content = []
     for src in ctx.files.srcs:
         # only format scala source files, not generated files
-        if src.path.endswith(".scala") and src.is_source:
+        if src.path.endswith(_scala_extension) and src.is_source:
             file = ctx.actions.declare_file("{}.fmt.output".format(src.short_path))
             files.append(file)
             ctx.actions.run(