add option to specify an alternate application name

Summary:
We currently hard-code the application name to be equivalent to the target name. However, when generating thrift targets, we can end up in the situation, where we will have duplicated application names in a dependency tree.

This option allows us to generate unique application names, either based on user overwrites, or based on the namespace.

Reviewed By: michalmuskala

Differential Revision: D69687014

fbshipit-source-id: a2b95992fd021e4b6baaabb555e506b9f05744ae

prelude/decls/erlang_rules.bzl

@@ -71,6 +71,9 @@ common_application_attributes = {
 
 rules_attributes = {
     "erlang_app": {
+        "app_name": attrs.option(attrs.string(), default = None, doc = """
+                This attribute allows the user to overwrite the Erlang application name, which otherwise defaults to the target name.
+            """),
         "app_src": attrs.option(attrs.source(), default = None, doc = """
                 The `app_src` field allows to optionally reference a `*.app.src` template file. This template file will then be used by
                 buck2 to generate the `*.app` output file in the applications `ebin/` directory. This is useful during the migration from
@@ -161,7 +164,7 @@ rules_attributes = {
         """),
     } | common_application_attributes,
     "erlang_app_includes": {
-        "application_name": attrs.string(),
+        "app_name": attrs.string(),
         "includes": attrs.list(attrs.source(), default = []),
         "_toolchain": attrs.toolchain_dep(default = "toolchains//:erlang-default"),
     },

prelude/erlang/erlang.bzl

@@ -35,6 +35,7 @@ def erlang_application(
         erlang_app_rule,
         erlang_app_includes_rule,
         name,
+        app_name = None,
         applications = [],
         included_applications = [],
         extra_includes = [],
@@ -57,6 +58,7 @@ def erlang_application(
     return [
         erlang_app_rule(
             name = name,
+            app_name = app_name,
             applications = normalized_applications,
             included_applications = normalized_included_applications,
             extra_includes = [
@@ -68,7 +70,7 @@ def erlang_application(
         ),
         erlang_app_includes_rule(
             name = _extra_include_name(name),
-            application_name = name,
+            app_name = name if app_name == None else app_name,
             includes = kwargs.get("includes", []),
             visibility = kwargs.get("visibility", None),
             labels = ["generated", "app_includes"],

prelude/erlang/erlang_application.bzl

@@ -32,6 +32,7 @@ load(
 load(
     ":erlang_utils.bzl",
     "action_identifier",
+    "app_name",
     "build_paths",
     "multidict_projection",
     "multidict_projection_key",
@@ -60,14 +61,14 @@ def erlang_application_impl(ctx: AnalysisContext) -> list[Provider]:
                                check_dependencies(ctx.attrs.extra_includes, [ErlangAppIncludeInfo]))
     dependencies = flatten_dependencies(ctx, all_direct_dependencies)
 
-    name = ctx.attrs.name
+    name = app_name(ctx)
     if name in dependencies and ErlangAppInfo in dependencies[name]:
         fail("cannot depend on an application with the same name: %s" % (dependencies[name].label,))
 
     return build_application(ctx, toolchains, dependencies)
 
 def build_application(ctx, toolchains, dependencies) -> list[Provider]:
-    name = ctx.attrs.name
+    name = app_name(ctx)
 
     build_environments = {}
     app_folders = {}
@@ -120,7 +121,7 @@ def build_application(ctx, toolchains, dependencies) -> list[Provider]:
     ]
 
 def _build_erlang_application(ctx: AnalysisContext, toolchain: Toolchain, dependencies: ErlAppDependencies) -> BuildEnvironment:
-    name = ctx.attrs.name
+    name = app_name(ctx)
 
     build_environment = erlang_build.prepare_build_environment(ctx, toolchain, dependencies)
 
@@ -214,7 +215,7 @@ def _generate_priv_dir(
         toolchain: Toolchain,
         build_environment: BuildEnvironment) -> BuildEnvironment:
     """Generate the application's priv dir."""
-    name = ctx.attrs.name
+    name = app_name(ctx)
 
     resources = ctx.attrs.resources
     priv_symlinks = {}
@@ -332,7 +333,7 @@ def link_output(
         link_path: str,
         build_environment: BuildEnvironment) -> Artifact:
     """Link application output folder in working dir root folder."""
-    name = ctx.attrs.name
+    name = app_name(ctx)
 
     ebin = build_environment.app_beams.values() + [build_environment.app_files[name]]
     include = build_environment.app_includes.values()
@@ -444,7 +445,7 @@ def build_app_info(
         app_folders: dict[str, Artifact],
         primary_app_folder: Artifact,
         start_dependencies: dict[str, list[StartDependencySet]]) -> Provider:
-    name = ctx.attrs.name
+    name = app_name(ctx)
 
     version = {
         toolchain.name: ctx.attrs.version

prelude/erlang/erlang_application_includes.bzl

@@ -23,7 +23,7 @@ def erlang_application_includes_impl(ctx: AnalysisContext) -> list[Provider]:
     """
 
     # prepare include directory for current app
-    name = ctx.attrs.application_name
+    name = ctx.attrs.app_name
 
     # input mapping
     input_mapping = {}

prelude/erlang/erlang_utils.bzl

@@ -23,9 +23,15 @@ def to_term_args(data: typing.Any) -> cmd_args:
         "",
     )
 
+def app_name(ctx: AnalysisContext) -> str:
+    if ctx.attrs.app_name == None:
+        return ctx.attrs.name
+    else:
+        return ctx.attrs.app_name
+
 # paths
 def app_file(ctx: AnalysisContext) -> str:
-    return paths.join(beam_dir(ctx), ctx.attrs.name + ".app")
+    return paths.join(beam_dir(ctx), app_name(ctx) + ".app")
 
 def beam_dir(ctx: AnalysisContext) -> str:
     return paths.join(ctx.attrs.name, "ebin")