fix: correctly advertise minimum supported version (#1065)

* feat: bump the latest supported version to 5.4.0
* feat: add gazelle and RBE minimum supported version tests
* feat: pip_parse_vendored example is now 5.4.0 compatible

.bazelci/presubmit.yml

@@ -17,6 +17,12 @@ buildifier:
   version: latest
   # keep this argument in sync with .pre-commit-config.yaml
   warnings: "all"
+.minimum_supported_version: &minimum_supported_version
+  # For testing minimum supported version.
+  # NOTE: Keep in sync with //:version.bzl
+  bazel: 5.4.0
+.minimum_supported_bzlmod_version: &minimum_supported_bzlmod_version
+  bazel: 6.0.0 # test minimum supported version of bazel for bzlmod tests
 .reusable_config: &reusable_config
   build_targets:
     - "--"
@@ -54,12 +60,24 @@ buildifier:
     - //tests:version_3_9_test
     - //tests:version_default_test
 tasks:
+  gazelle_extension_min:
+    <<: *minimum_supported_version
+    name: Test the Gazelle extension using minimum supported Bazel version
+    platform: ubuntu2004
+    build_targets: ["//..."]
+    test_targets: ["//..."]
+    working_directory: gazelle
   gazelle_extension:
     name: Test the Gazelle extension
     platform: ubuntu2004
     build_targets: ["//..."]
     test_targets: ["//..."]
     working_directory: gazelle
+  ubuntu_min:
+    <<: *minimum_supported_version
+    <<: *reusable_config
+    name: Default test on Ubuntu using minimum supported Bazel version
+    platform: ubuntu2004
   ubuntu:
     <<: *reusable_config
     name: Default test on Ubuntu
@@ -78,13 +96,27 @@ tasks:
     platform: windows
     test_flags:
       - "--test_tag_filters=-integration-test,-fix-windows"
+
+  rbe_min:
+    <<: *minimum_supported_version
+    <<: *reusable_config
+    name: Test on RBE using minimum supported Bazel version
+    platform: rbe_ubuntu1604
+    test_flags:
+      - "--test_tag_filters=-integration-test,-acceptance-test"
   rbe:
     <<: *reusable_config
     name: Test on RBE
     platform: rbe_ubuntu1604
     test_flags:
       - "--test_tag_filters=-integration-test,-acceptance-test"
 
+  integration_test_build_file_generation_ubuntu_minimum_supported:
+    <<: *minimum_supported_version
+    <<: *reusable_build_test_all
+    name: build_file_generation integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: examples/build_file_generation
+    platform: ubuntu2004
   integration_test_build_file_generation_ubuntu:
     <<: *reusable_build_test_all
     name: build_file_generation integration tests on Ubuntu
@@ -106,6 +138,13 @@ tasks:
     working_directory: examples/build_file_generation
     platform: windows
 
+  integration_test_bzlmod_ubuntu_min:
+    <<: *minimum_supported_bzlmod_version
+    <<: *reusable_build_test_all
+    <<: *coverage_targets_example_bzlmod
+    name: bzlmod integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: examples/bzlmod
+    platform: ubuntu2004
   integration_test_bzlmod_ubuntu:
     <<: *reusable_build_test_all
     <<: *coverage_targets_example_bzlmod
@@ -131,6 +170,12 @@ tasks:
     working_directory: examples/bzlmod
     platform: windows
 
+  integration_test_multi_python_versions_ubuntu_min:
+    <<: *minimum_supported_version
+    <<: *reusable_build_test_all
+    name: multi_python_versions integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: examples/multi_python_versions
+    platform: ubuntu2004
   integration_test_multi_python_versions_ubuntu:
     <<: *reusable_build_test_all
     <<: *coverage_targets_example_multi_python
@@ -156,6 +201,12 @@ tasks:
     working_directory: examples/multi_python_versions
     platform: windows
 
+  integration_test_pip_install_ubuntu_min:
+    <<: *minimum_supported_version
+    <<: *reusable_build_test_all
+    name: pip_install integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: examples/pip_install
+    platform: ubuntu2004
   integration_test_pip_install_ubuntu:
     <<: *reusable_build_test_all
     name: pip_install integration tests on Ubuntu
@@ -177,6 +228,12 @@ tasks:
     working_directory: examples/pip_install
     platform: windows
 
+  integration_test_pip_parse_ubuntu_min:
+    <<: *minimum_supported_version
+    <<: *reusable_build_test_all
+    name: pip_parse integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: examples/pip_parse
+    platform: ubuntu2004
   integration_test_pip_parse_ubuntu:
     <<: *reusable_build_test_all
     name: pip_parse integration tests on Ubuntu
@@ -198,6 +255,12 @@ tasks:
     working_directory: examples/pip_parse
     platform: windows
 
+  integration_test_pip_parse_vendored_ubuntu_min:
+    <<: *minimum_supported_version
+    <<: *reusable_build_test_all
+    name: pip_parse_vendored integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: examples/pip_parse_vendored
+    platform: ubuntu2004
   integration_test_pip_parse_vendored_ubuntu:
     <<: *reusable_build_test_all
     name: pip_parse_vendored integration tests on Ubuntu
@@ -216,6 +279,12 @@ tasks:
   # We don't run pip_parse_vendored under Windows as the file checked in is
   # generated from a repository rule containing OS-specific rendered paths.
 
+  integration_test_py_proto_library_ubuntu_min:
+    <<: *minimum_supported_version
+    <<: *reusable_build_test_all
+    name: py_proto_library integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: examples/py_proto_library
+    platform: ubuntu2004
   integration_test_py_proto_library_ubuntu:
     <<: *reusable_build_test_all
     name: py_proto_library integration tests on Ubuntu
@@ -238,6 +307,13 @@ tasks:
     platform: windows
 
   # Check the same using bzlmod as well
+  integration_test_py_proto_library_bzlmod_ubuntu_min:
+    <<: *minimum_supported_bzlmod_version
+    <<: *common_bzlmod_flags
+    <<: *reusable_build_test_all
+    name: py_proto_library bzlmod integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: examples/py_proto_library
+    platform: ubuntu2004
   integration_test_py_proto_library_bzlmod_ubuntu:
     <<: *reusable_build_test_all
     <<: *common_bzlmod_flags
@@ -263,6 +339,12 @@ tasks:
     working_directory: examples/py_proto_library
     platform: windows
 
+  integration_test_pip_repository_annotations_ubuntu_min:
+    <<: *minimum_supported_version
+    <<: *reusable_build_test_all
+    name: pip_repository_annotations integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: examples/pip_repository_annotations
+    platform: ubuntu2004
   integration_test_pip_repository_annotations_ubuntu:
     <<: *reusable_build_test_all
     name: pip_repository_annotations integration tests on Ubuntu
@@ -284,6 +366,12 @@ tasks:
     working_directory: examples/pip_repository_annotations
     platform: windows
 
+  integration_test_compile_pip_requirements_ubuntu_min:
+    <<: *minimum_supported_version
+    <<: *reusable_build_test_all
+    name: compile_pip_requirements integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: tests/compile_pip_requirements
+    platform: ubuntu2004
   integration_test_compile_pip_requirements_ubuntu:
     <<: *reusable_build_test_all
     name: compile_pip_requirements integration tests on Ubuntu
@@ -333,6 +421,12 @@ tasks:
     - "bazel run //:requirements.update"
     - "git diff --exit-code"
 
+  integration_test_pip_repository_entry_points_ubuntu_min:
+    <<: *minimum_supported_version
+    <<: *reusable_build_test_all
+    name: pip_repository_entry_points integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: tests/pip_repository_entry_points
+    platform: ubuntu2004
   integration_test_pip_repository_entry_points_ubuntu:
     <<: *reusable_build_test_all
     name: pip_repository_entry_points integration tests on Ubuntu
@@ -354,6 +448,12 @@ tasks:
     working_directory: tests/pip_repository_entry_points
     platform: windows
 
+  integration_test_ignore_root_user_error_ubuntu_min:
+    <<: *minimum_supported_version
+    <<: *reusable_build_test_all
+    name: ignore_root_user_error integration tests on Ubuntu using minimum supported Bazel version
+    working_directory: tests/ignore_root_user_error
+    platform: ubuntu2004
   integration_test_ignore_root_user_error_ubuntu:
     <<: *reusable_build_test_all
     name: ignore_root_user_error integration tests on Ubuntu

BUILD.bazel

@@ -31,6 +31,7 @@ filegroup(
         "WORKSPACE",
         "internal_deps.bzl",
         "internal_setup.bzl",
+        "version.bzl",
         "//python:distribution",
         "//python/pip_install:distribution",
         "//tools:distribution",

docs/BUILD.bazel

@@ -67,6 +67,7 @@ bzl_library(
     ],
     deps = [
         ":defs",
+        "//:version.bzl",
     ],
 )
 

examples/pip_parse_vendored/BUILD.bazel

@@ -17,6 +17,9 @@ genrule(
         "cat $<",
         # Insert our load statement after the existing one so we don't produce a file with buildifier warnings
         """sed -e '/^load.*/i\\'$$'\\n''load("@python39//:defs.bzl", "interpreter")'""",
+        # Replace the bazel 6.0.0 specific comment with something that bazel 5.4.0 would produce.
+        # This enables this example to be run as a test under bazel 5.4.0.
+        """sed -e 's#@//#//#'""",
         """tr "'" '"' """,
         """sed 's#"@python39_.*//:bin/python3"#interpreter#' >$@""",
     ]),

examples/pip_parse_vendored/requirements.bzl

@@ -1,7 +1,7 @@
 """Starlark representation of locked requirements.
 
 @generated by rules_python pip_parse repository rule
-from @//:requirements.txt
+from //:requirements.txt
 """
 
 load("@python39//:defs.bzl", "interpreter")

python/pip_install/repositories.bzl

@@ -17,6 +17,7 @@
 load("@bazel_skylib//lib:versions.bzl", "versions")
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
+load("//:version.bzl", "MINIMUM_BAZEL_VERSION")
 
 _RULE_DEPS = [
     (
@@ -133,7 +134,7 @@ def pip_install_dependencies():
     # Give the user an obvious error to upgrade rather than some obscure missing symbol later.
     # It's not guaranteed that users call this function, but it's used by all the pip fetch
     # repository rules so it's likely that most users get the right error.
-    versions.check("4.0.0")
+    versions.check(MINIMUM_BAZEL_VERSION)
 
     for (name, url, sha256) in _RULE_DEPS:
         maybe(

version.bzl

@@ -19,14 +19,20 @@
 # in .bazelversion.
 BAZEL_VERSION = "6.0.0"
 
+# NOTE: Keep in sync with .bazelci/presubmit.yml
+# This is the minimum supported bazel version, that we have some tests for.
+MINIMUM_BAZEL_VERSION = "5.4.0"
+
 # Versions of Bazel which users should be able to use.
 # Ensures we don't break backwards-compatibility,
 # accidentally forcing users to update their LTS-supported bazel.
 # These are the versions used when testing nested workspaces with
 # bazel_integration_test.
 SUPPORTED_BAZEL_VERSIONS = [
-    # TODO: add LTS versions of bazel like 1.0.0, 2.0.0
     BAZEL_VERSION,
+    # TODO @aignas 2023-02-15: the integration tests currently support
+    # only a single element in this array.
+    #MINIMUM_BAZEL_VERSION,
 ]
 
 def bazel_version_to_binary_label(version):