Replace scala_deps.toolchains with tag classes

mbland · mbland · commit a2e69e0a4d55 · 2025-04-20T23:31:44.000-04:00
Replaces the `scala_deps.toolchains` tag class, which contained boolean parameters for selecting toolchains, with a series of individual tag classes for each toolchain. Suggested by @simuons in the following comment as an alternative implementation that could allow for adding attributes to each toolchain's tag class. - bazel-contrib#1722 (comment) We already had tag classes for `scalafmt`, `scala_proto`, and `twitter_scrooge` options. Now the presence of these tag classes, along with the tag classes added in this commit, translates to a `True` argument for `scala_toolchains()`.
diff --git a/MODULE.bazel b/MODULE.bazel
@@ -77,6 +77,7 @@ use_repo(
     "rules_scala_toolchains",
     "scala_compiler_sources",
 )
+scala_deps.scala()
 
 # Register some of our testing toolchains first when building our repo.
 register_toolchains(
@@ -100,15 +101,13 @@ dev_deps = use_extension(
     "scala_deps",
     dev_dependency = True,
 )
-dev_deps.toolchains(
-    jmh = True,
-    junit = True,
-    scala_proto = True,
-    scalafmt = True,
-    scalatest = True,
-    specs2 = True,
-    twitter_scrooge = True,
-)
+dev_deps.jmh()
+dev_deps.junit()
+dev_deps.scala_proto()
+dev_deps.scalafmt()
+dev_deps.scalatest()
+dev_deps.specs2()
+dev_deps.twitter_scrooge()
 use_repo(
     dev_deps,
     "scala_proto_rules_scalapb_compilerplugin",
diff --git a/README.md b/README.md
@@ -75,17 +75,18 @@ scala_deps = use_extension(
     "scala_deps",
 )
 
-# Defines a default toolchain repo for the configured Scala version that
-# loads Maven deps like the Scala compiler and standard libs. Enable other builtin
-# toolchains by setting their corresponding parameters to `True`. See the
-# documentation of `_toolchains_attrs` from `scala/extensions/deps.bzl` for all
-# builtin toolchain configuration options.
+# Defines a default toolchain repo for the configured Scala version that loads
+# Maven deps like the Scala compiler and standard libs. Enable and configure
+# other builtin toolchains by instantiating their corresponding tag classes.
+# See the documentation in `scala/extensions/deps.bzl` for all builtin
+# toolchain configuration options.
 #
 # On production projects, you may consider defining a custom toolchain to use
-# your project's required dependencies instead. In that case, you can omit
-# `scala_deps` or explicitly set `scala = False` if you use it to instantiate
-# other builtin toolchains.
-scala_deps.toolchains()
+# your project's required dependencies instead. In that case, you can omit using
+# the module extension and this next line altogether. Or, you can still use the
+# module extension to instantiate other optional `rules_scala` toolchains
+# without it.
+scala_deps.scala()
 
 # The remaining items are optional, enabling the precompiled protocol compiler
 # toolchain via `--incompatible_enable_proto_toolchain_resolution`. See the
@@ -921,18 +922,23 @@ docs/scala_toolchain.md#b-defining-your-own-scala_toolchain), don't use
 `scala_deps` or `scala_toolchains()` if you don't need any other builtin
 toolchains.
 
-If you do need other builtin toolchains, then set `scala = False`:
+If you do need other builtin toolchains when using Bzlmod, then use the module
+extension and only instantiate the tag classes to the corresponding toolchains.
+
+If you do need other builtin toolchains when using `WORKSPACE`, then set `scala
+= False`.
 
 ```py
 # MODULE.bazel
-scala_deps.toolchains(
-    scala = False,
-    # ...other toolchain parameters...
-)
+scala_deps.scala_proto()
+scala_deps.twitter_scrooge()
+# ...other scala_deps tag class instantations...
 
 # WORKSPACE
 scala_toolchains(
     scala = False,
+    scala_proto = True,
+    twitter_scrooge = True,
     # ...other toolchain parameters...
 )
 ```
@@ -972,10 +978,9 @@ scala_deps = use_extension(
     "@rules_scala//scala/extensions:deps.bzl",
     "scala_deps",
 )
-scala_deps.toolchains(
-    scalafmt = True,
-    scalatest = True,
-)
+scala_deps.scala()
+scala_deps.scalafmt()
+scala_deps.scalatest()
 ```
 
 The module extensions call `scala_config()` and `scala_toolchains()`
@@ -1384,9 +1389,7 @@ To access these repositories under Bzlmod, you'll need to add the following to
 your `MODULE.bazel` file:
 
 ```py
-scala_deps.toolchains(
-    twitter_scrooge = True,
-)
+scala_deps.twitter_scrooge()
 use_repo(
     scala_deps,
     "io_bazel_rules_scala_guava",
diff --git a/dt_patches/test_dt_patches/MODULE.bazel b/dt_patches/test_dt_patches/MODULE.bazel
@@ -51,6 +51,7 @@ scala_deps.settings(
     fetch_sources = True,
     validate_scala_version = False,
 )
+scala_deps.scala()
 
 scala_protoc = use_extension(
     "@rules_scala//scala/extensions:protoc.bzl",
diff --git a/dt_patches/test_dt_patches_user_srcjar/MODULE.bazel b/dt_patches/test_dt_patches_user_srcjar/MODULE.bazel
@@ -61,6 +61,7 @@ scala_deps.settings(
     fetch_sources = True,
     validate_scala_version = False,
 )
+scala_deps.scala()
 
 # The `scala_deps.compiler_srcjar()` tag prevents some of the kinds of errors
 # represented in the corresponding `WORKSPACE` file, so we have to force
diff --git a/examples/crossbuild/MODULE.bazel b/examples/crossbuild/MODULE.bazel
@@ -25,13 +25,13 @@ use_repo(scala_config, "rules_scala_config")
 scala_deps = use_extension(
     "@rules_scala//scala/extensions:deps.bzl",
     "scala_deps",
+    dev_dependency = True,
 )
 scala_deps.settings(
     fetch_sources = True,
 )
-scala_deps.toolchains(
-    scalatest = True,
-)
+scala_deps.scala()
+scala_deps.scalatest()
 
 scala_protoc = use_extension(
     "@rules_scala//scala/extensions:protoc.bzl",
diff --git a/examples/overridden_artifacts/MODULE.bazel b/examples/overridden_artifacts/MODULE.bazel
@@ -19,10 +19,12 @@ scala_config.settings(
 scala_deps = use_extension(
     "@rules_scala//scala/extensions:deps.bzl",
     "scala_deps",
+    dev_dependency = True,
 )
 scala_deps.settings(
     fetch_sources = False,
 )
+scala_deps.scala()
 
 # Deliberately set for Scala 3.3 and 2.13 versions less than the most
 # recently supported. See the `scala_version` setting at the top of
@@ -54,9 +56,7 @@ scala_deps.overridden_artifact(
     artifact = "org.scala-lang:scala-library:2.13.14",
     sha256 = "43e0ca1583df1966eaf02f0fbddcfb3784b995dd06bfc907209347758ce4b7e3",
 )
-scala_deps.toolchains(
-    scalatest = True,
-)
+scala_deps.scalatest()
 
 scala_protoc = use_extension(
     "@rules_scala//scala/extensions:protoc.bzl",
diff --git a/examples/scala3/MODULE.bazel b/examples/scala3/MODULE.bazel
@@ -15,6 +15,7 @@ scala_deps = use_extension(
 scala_deps.settings(
     fetch_sources = True,
 )
+scala_deps.scala()
 
 scala_protoc = use_extension(
     "@rules_scala//scala/extensions:protoc.bzl",
diff --git a/examples/semanticdb/MODULE.bazel b/examples/semanticdb/MODULE.bazel
@@ -23,6 +23,7 @@ scala_deps = use_extension(
 scala_deps.settings(
     fetch_sources = True,
 )
+scala_deps.scala()
 
 scala_protoc = use_extension(
     "@rules_scala//scala/extensions:protoc.bzl",
diff --git a/examples/testing/multi_frameworks_toolchain/MODULE.bazel b/examples/testing/multi_frameworks_toolchain/MODULE.bazel
@@ -24,15 +24,15 @@ use_repo(scala_config, "rules_scala_config")
 scala_deps = use_extension(
     "@rules_scala//scala/extensions:deps.bzl",
     "scala_deps",
+    dev_dependency = True,
 )
 scala_deps.settings(
     fetch_sources = True,
 )
-scala_deps.toolchains(
-    junit = True,
-    scalatest = True,
-    specs2 = True,
-)
+scala_deps.scala()
+scala_deps.junit()
+scala_deps.scalatest()
+scala_deps.specs2()
 
 # Under normal circumstances, the above `scala_deps.toolchains()` registration
 # would be all you need. rules_scala will set up and register the toolchains
diff --git a/examples/testing/scalatest_repositories/MODULE.bazel b/examples/testing/scalatest_repositories/MODULE.bazel
@@ -11,13 +11,13 @@ local_path_override(
 scala_deps = use_extension(
     "@rules_scala//scala/extensions:deps.bzl",
     "scala_deps",
+    dev_dependency = True,
 )
 scala_deps.settings(
     fetch_sources = True,
 )
-scala_deps.toolchains(
-    scalatest = True,
-)
+scala_deps.scala()
+scala_deps.scalatest()
 
 scala_protoc = use_extension(
     "@rules_scala//scala/extensions:protoc.bzl",
diff --git a/examples/testing/specs2_junit_repositories/MODULE.bazel b/examples/testing/specs2_junit_repositories/MODULE.bazel
@@ -11,13 +11,13 @@ local_path_override(
 scala_deps = use_extension(
     "@rules_scala//scala/extensions:deps.bzl",
     "scala_deps",
+    dev_dependency = True,
 )
 scala_deps.settings(
     fetch_sources = True,
 )
-scala_deps.toolchains(
-    specs2 = True,
-)
+scala_deps.scala()
+scala_deps.specs2()
 
 scala_protoc = use_extension(
     "@rules_scala//scala/extensions:protoc.bzl",
diff --git a/scala/extensions/deps.bzl b/scala/extensions/deps.bzl
diff --git a/test_cross_build/MODULE.bazel b/test_cross_build/MODULE.bazel
diff --git a/test_version/MODULE.bazel.template b/test_version/MODULE.bazel.template
diff --git a/third_party/test/example_external_workspace/MODULE.bazel b/third_party/test/example_external_workspace/MODULE.bazel
diff --git a/third_party/test/proto/MODULE.bazel b/third_party/test/proto/MODULE.bazel

Original file line number	Diff line number	Diff line change
`@@ -51,6 +51,7 @@ scala_deps.settings(`
`51`	`51`	`fetch_sources = True,`
`52`	`52`	`validate_scala_version = False,`
`53`	`53`	`)`
	`54`	`+scala_deps.scala()`
`54`	`55`
`55`	`56`	`scala_protoc = use_extension(`
`56`	`57`	`"@rules_scala//scala/extensions:protoc.bzl",`
Original file line number	Diff line number	Diff line change
`@@ -61,6 +61,7 @@ scala_deps.settings(`
`61`	`61`	`fetch_sources = True,`
`62`	`62`	`validate_scala_version = False,`
`63`	`63`	`)`
	`64`	`+scala_deps.scala()`
`64`	`65`
`65`	`66`	# The `scala_deps.compiler_srcjar()` tag prevents some of the kinds of errors
`66`	`67`	# represented in the corresponding `WORKSPACE` file, so we have to force
Original file line number	Diff line number	Diff line change
`@@ -15,6 +15,7 @@ scala_deps = use_extension(`
`15`	`15`	`scala_deps.settings(`
`16`	`16`	`fetch_sources = True,`
`17`	`17`	`)`
	`18`	`+scala_deps.scala()`
`18`	`19`
`19`	`20`	`scala_protoc = use_extension(`
`20`	`21`	`"@rules_scala//scala/extensions:protoc.bzl",`
Original file line number	Diff line number	Diff line change
`@@ -23,6 +23,7 @@ scala_deps = use_extension(`
`23`	`23`	`scala_deps.settings(`
`24`	`24`	`fetch_sources = True,`
`25`	`25`	`)`
	`26`	`+scala_deps.scala()`
`26`	`27`
`27`	`28`	`scala_protoc = use_extension(`
`28`	`29`	`"@rules_scala//scala/extensions:protoc.bzl",`