feat(elixir_app): add name, target_compatible_with, testonly and tags

.github/workflows/test.yaml

@@ -71,6 +71,14 @@ jobs:
         run: |
           grep -E "Result: 2 passed|2 tests, 0 failures" \
             bazel-testlogs/two_file_test/test.log
+      - name: INCOMPATIBLE APP IS SKIPPED
+        working-directory: test
+        # //... above skipped it. Asking for it directly must fail.
+        run: |
+          if bazelisk build //:incompatible_app; then
+            echo "//:incompatible_app built despite target_compatible_with"
+            exit 1
+          fi
       - name: EXPECTED FAILURES FAIL
         working-directory: test
         run: |

elixir_app.bzl

@@ -4,25 +4,44 @@ load("//private:elixir_bytecode.bzl", "elixir_bytecode")
 load("//private:elixir_ebin_dir.bzl", "elixir_ebin_dir")
 load("//private:erlang_app_filter_module_conflicts.bzl", "erlang_app_filter_module_conflicts")
 
+def _prefixed(name, suffix, sep):
+    # The default name keeps the internal names and output dirs that
+    # elixir_app has always used, so existing users see no change.
+    if name == "erlang_app":
+        return suffix
+    return name + sep + suffix
+
 def elixir_app(
+        name = "erlang_app",
         app_name = None,
         extra_apps = [],
         srcs = None,
         data = [],
         elixirc_opts = [],
         ez_deps = [],
         deps = [],
+        target_compatible_with = None,
+        testonly = False,
+        tags = None,
         **kwargs):
     """compiles elixir sources in a manner compatible with @rules_erlang
 
     Args:
+      name: Name of the final ErlangAppInfo target. With the default
+          "erlang_app", the internal targets are named beam_files,
+          app_file, ebin and elixir_without_app_overlap. With any other
+          name they are prefixed with "<name>_", and their output dirs
+          with "<name>/", so several apps can share a package.
       app_name: Name of the application
       extra_apps: additional apps (elixir is always included) injected into
           the .app file
       srcs: Sources. Defaults to "lib/**/*.ex"
       elixirc_opts: elixirc options
       ez_deps: Dependencies that are .ez files
       deps: ErlangAppInfo labels
+      target_compatible_with: Passed to every generated target
+      testonly: Passed to every generated target
+      tags: Passed to every generated target
       **kwargs: Additional args passed to the underlying app_file rule, such
           as app_description
 
@@ -34,45 +53,58 @@ def elixir_app(
             "lib/**/*.ex",
         ])
 
+    beam_files = _prefixed(name, "beam_files", "_")
+    app_file_name = _prefixed(name, "app_file", "_")
+    ebin = _prefixed(name, "ebin", "_")
+    without_overlap = _prefixed(name, "elixir_without_app_overlap", "_")
+    common = dict(
+        target_compatible_with = target_compatible_with,
+        testonly = testonly,
+        tags = tags,
+    )
+
     elixir_bytecode(
-        name = "beam_files",
+        name = beam_files,
         srcs = srcs,
         data = data,
-        dest = "beam_files",
+        dest = _prefixed(name, "beam_files", "/"),
         elixirc_opts = elixirc_opts,
         ez_deps = ez_deps,
         deps = deps,
+        **common
     )
 
     app_file(
-        name = "app_file",
+        name = app_file_name,
         out = "%s.app" % app_name,
         app_name = app_name,
         extra_apps = ["elixir"] + extra_apps,
-        modules = [":beam_files"],
-        **kwargs
+        modules = [":" + beam_files],
+        **(common | kwargs)
     )
 
     elixir_ebin_dir(
-        name = "ebin",
-        beam_files_dir = ":beam_files",
-        app_file = ":app_file",
-        dest = "ebin",
+        name = ebin,
+        beam_files_dir = ":" + beam_files,
+        app_file = ":" + app_file_name,
+        dest = _prefixed(name, "ebin", "/"),
+        **common
     )
 
     erlang_app_filter_module_conflicts(
-        name = "elixir_without_app_overlap",
-        dest = "unconsolidated",
+        name = without_overlap,
+        dest = _prefixed(name, "unconsolidated", "/"),
         src = Label("@rules_elixir//elixir:elixir"),
-        without = [":ebin"],
+        without = [":" + ebin],
+        **common
     )
 
     erlang_app_info(
-        name = "erlang_app",
+        name = name,
         srcs = srcs,
         hdrs = [],
         app_name = app_name,
-        beam = [":ebin"],
+        beam = [":" + ebin],
         extra_apps = extra_apps,
         # allow_empty: plenty of Hex packages ship no LICENSE file (ash among them), and
         # with --incompatible_disallow_empty_glob on -- the default since Bazel 7 -- an
@@ -81,6 +113,7 @@ def elixir_app(
         priv = [],
         visibility = ["//visibility:public"],
         deps = [
-            ":elixir_without_app_overlap",
+            ":" + without_overlap,
         ] + deps,
+        **common
     )

test/BUILD.bazel

@@ -1,3 +1,4 @@
+load("@bazel_skylib//rules:build_test.bzl", "build_test")
 load("@rules_elixir//:elixir_app.bzl", "elixir_app")
 load("@rules_elixir//:ex_unit_test.bzl", "ex_unit_test")
 load(
@@ -15,6 +16,65 @@ elixir_app(
     ],
 )
 
+# A second app in the same package. Its internal targets and output dirs
+# are prefixed with its name, so they do not clash with the default ones.
+# testonly is forwarded to every generated target; if it were not, the
+# final target would fail analysis because it depends on testonly ones.
+elixir_app(
+    name = "other",
+    app_name = "other",
+    srcs = ["other_lib/other.ex"],
+    testonly = True,
+    tags = ["other_app"],
+)
+
+build_test(
+    name = "app_targets_test",
+    targets = [
+        ":erlang_app",
+        ":beam_files",
+        ":app_file",
+        ":ebin",
+        ":elixir_without_app_overlap",
+        ":other",
+        ":other_beam_files",
+        ":other_app_file",
+        ":other_ebin",
+        ":other_elixir_without_app_overlap",
+    ],
+)
+
+sh_test(
+    name = "app_names_test",
+    size = "small",
+    srcs = ["app_names_test.sh"],
+    args = [
+        "beam_files=$(rootpath :beam_files)",
+        "ebin=$(rootpath :ebin)",
+        "unconsolidated=$(rootpath :elixir_without_app_overlap)",
+        "other/beam_files=$(rootpath :other_beam_files)",
+        "other/ebin=$(rootpath :other_ebin)",
+        "other/unconsolidated=$(rootpath :other_elixir_without_app_overlap)",
+    ],
+    data = [
+        ":beam_files",
+        ":ebin",
+        ":elixir_without_app_overlap",
+        ":other_beam_files",
+        ":other_ebin",
+        ":other_elixir_without_app_overlap",
+    ],
+)
+
+# Incompatible with every platform, so //... skips all of its targets.
+# .github/workflows/test.yaml checks that building it directly fails.
+elixir_app(
+    name = "incompatible_app",
+    app_name = "incompatible_app",
+    srcs = ["incompatible_lib/incompatible.ex"],
+    target_compatible_with = ["@platforms//:incompatible"],
+)
+
 escript_archive(
     name = "basic",
     app = ":erlang_app",

test/MODULE.bazel

@@ -3,6 +3,10 @@ module(
     version = "0.1.0",
 )
 
+bazel_dep(
+    name = "bazel_skylib",
+    version = "1.9.2",
+)
 bazel_dep(
     name = "rules_erlang",
     version = "3.18.0",
@@ -23,6 +27,12 @@ bazel_dep(
     version = "0.8.0",
 )
 
+# target_compatible_with in BUILD.bazel uses @platforms//:incompatible.
+bazel_dep(
+    name = "platforms",
+    version = "1.1.0",
+)
+
 # See the note in the root MODULE.bazel. This is a separate module, so it needs
 # its own override; the one in the ruleset it depends on does not carry over.
 git_override(

test/app_names_test.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+# Each argument is "<expected path>=<rootpath>". The targets are in the
+# root package, so the rootpath of an output dir is its dest. The output
+# dirs of the default-named elixir_app must not gain a prefix.
+set -euo pipefail
+
+for arg in "$@"; do
+    expected="${arg%%=*}"
+    path="${arg#*=}"
+    path="${path#./}"
+    if [ "$path" != "$expected" ]; then
+        echo "FAIL: output dir is $path, expected $expected" >&2
+        exit 1
+    fi
+    if [ ! -d "$path" ]; then
+        echo "FAIL: $path is not a directory" >&2
+        exit 1
+    fi
+    echo "ok: $path"
+done

test/incompatible_lib/incompatible.ex

@@ -0,0 +1,3 @@
+defmodule Incompatible do
+  def hello, do: :world
+end

test/other_lib/other.ex

@@ -0,0 +1,3 @@
+defmodule Other do
+  def hello, do: :world
+end