refactor: use fallback versions and next_breaking_version for build system config

Copilot · nathanjmcdougall · Copilot · commit 520b09036e7a · 2026-03-25T00:29:46.000Z
- Add FALLBACK_HATCHLING_VERSION = "1.29.0" to _fallback.py - Extract next_breaking_version() generic helper into _fallback.py - Refactor next_breaking_uv_version() to delegate to next_breaking_version() - Update _BUILD_SYSTEM_CONFIG to use FALLBACK_UV_VERSION, FALLBACK_HATCHLING_VERSION and next_breaking_version() instead of hard-coded version bounds - Add TestFallbackHatchlingVersion and TestNextBreakingVersion tests Co-authored-by: nathanjmcdougall <18602289+nathanjmcdougall@users.noreply.github.com> Agent-Logs-Url: https://github.com/usethis-python/usethis-python/sessions/0ab118f5-5448-457b-a6aa-6740f6b46a5d
diff --git a/src/usethis/_backend/uv/version.py b/src/usethis/_backend/uv/version.py
@@ -1,10 +1,8 @@
 import json
 
-from packaging.version import Version
-
 from usethis._backend.uv.call import call_uv_subprocess
 from usethis._backend.uv.errors import UVSubprocessFailedError
-from usethis._fallback import FALLBACK_UV_VERSION
+from usethis._fallback import FALLBACK_UV_VERSION, next_breaking_version
 
 
 def get_uv_version() -> str:
@@ -26,7 +24,4 @@ def next_breaking_uv_version(version: str) -> str:
     For versions with major >= 1, bumps the major version (e.g. 1.0.2 -> 2.0.0).
     For versions with major == 0, bumps the minor version (e.g. 0.10.2 -> 0.11.0).
     """
-    v = Version(version)
-    if v.major >= 1:
-        return f"{v.major + 1}.0.0"
-    return f"0.{v.minor + 1}.0"
+    return next_breaking_version(version)
diff --git a/src/usethis/_fallback.py b/src/usethis/_fallback.py
@@ -5,9 +5,24 @@
 ``tests/usethis/test_fallback.py``.
 """
 
+from packaging.version import Version
+
 FALLBACK_UV_VERSION = "0.10.12"
+FALLBACK_HATCHLING_VERSION = "1.29.0"
 FALLBACK_PRE_COMMIT_VERSION = "4.5.1"
 FALLBACK_RUFF_VERSION = "v0.15.7"
 FALLBACK_SYNC_WITH_UV_VERSION = "v0.5.0"
 FALLBACK_PYPROJECT_FMT_VERSION = "v2.20.0"
 FALLBACK_CODESPELL_VERSION = "v2.4.2"
+
+
+def next_breaking_version(version: str) -> str:
+    """Get the next breaking version for a version string, following semver.
+
+    For versions with major >= 1, bumps the major version (e.g. 1.0.2 -> 2.0.0).
+    For versions with major == 0, bumps the minor version (e.g. 0.10.2 -> 0.11.0).
+    """
+    v = Version(version)
+    if v.major >= 1:
+        return f"{v.major + 1}.0.0"
+    return f"0.{v.minor + 1}.0"
diff --git a/src/usethis/_init.py b/src/usethis/_init.py
@@ -10,14 +10,29 @@
 from usethis._config import usethis_config
 from usethis._console import tick_print
 from usethis._deps import get_project_deps
+from usethis._fallback import (
+    FALLBACK_HATCHLING_VERSION,
+    FALLBACK_UV_VERSION,
+    next_breaking_version,
+)
 from usethis._file.pyproject_toml.io_ import PyprojectTOMLManager
 from usethis._integrations.project.name import get_project_name
 from usethis._types.backend import BackendEnum
 from usethis._types.build_backend import BuildBackendEnum
 
 _BUILD_SYSTEM_CONFIG: dict[BuildBackendEnum, tuple[list[str], str]] = {
-    BuildBackendEnum.hatch: (["hatchling"], "hatchling.build"),
-    BuildBackendEnum.uv: (["uv_build>=0.10.12,<0.11.0"], "uv_build"),
+    BuildBackendEnum.hatch: (
+        [
+            f"hatchling>={FALLBACK_HATCHLING_VERSION},<{next_breaking_version(FALLBACK_HATCHLING_VERSION)}"
+        ],
+        "hatchling.build",
+    ),
+    BuildBackendEnum.uv: (
+        [
+            f"uv_build>={FALLBACK_UV_VERSION},<{next_breaking_version(FALLBACK_UV_VERSION)}"
+        ],
+        "uv_build",
+    ),
 }
 
 
diff --git a/tests/usethis/test_fallback.py b/tests/usethis/test_fallback.py
@@ -5,11 +5,13 @@
 from usethis._config import usethis_config
 from usethis._fallback import (
     FALLBACK_CODESPELL_VERSION,
+    FALLBACK_HATCHLING_VERSION,
     FALLBACK_PRE_COMMIT_VERSION,
     FALLBACK_PYPROJECT_FMT_VERSION,
     FALLBACK_RUFF_VERSION,
     FALLBACK_SYNC_WITH_UV_VERSION,
     FALLBACK_UV_VERSION,
+    next_breaking_version,
 )
 from usethis._integrations.ci.github.errors import GitHubTagError
 from usethis._integrations.ci.github.tags import get_github_latest_tag
@@ -40,6 +42,22 @@ def test_latest_version(self):
             raise err
 
 
+class TestFallbackHatchlingVersion:
+    @pytest.mark.usefixtures("_vary_network_conn")
+    def test_latest_version(self):
+        if os.getenv("CI"):
+            pytest.skip("Avoid flaky pipelines by testing version bumps manually")
+
+        try:
+            assert (
+                get_github_latest_tag(owner="pypa", repo="hatch")
+                == f"hatchling-v{FALLBACK_HATCHLING_VERSION}"
+            )
+        except GitHubTagError as err:
+            _skip_on_github_error(err)
+            raise err
+
+
 class TestPreCommitVersion:
     @pytest.mark.usefixtures("_vary_network_conn")
     def test_latest_version(self):
@@ -120,3 +138,20 @@ def test_latest_version(self):
         except GitHubTagError as err:
             _skip_on_github_error(err)
             raise err
+
+
+class TestNextBreakingVersion:
+    def test_pre_one_bumps_minor(self):
+        assert next_breaking_version("0.10.2") == "0.11.0"
+
+    def test_post_one_bumps_major(self):
+        assert next_breaking_version("1.0.2") == "2.0.0"
+
+    def test_pre_one_zero_minor(self):
+        assert next_breaking_version("0.0.5") == "0.1.0"
+
+    def test_exact_one(self):
+        assert next_breaking_version("1.0.0") == "2.0.0"
+
+    def test_high_major(self):
+        assert next_breaking_version("3.2.1") == "4.0.0"
