feat: add option to control which PRs run workflows in a stack

adbc_drivers_dev/generate.py

@@ -208,6 +208,13 @@ class LangConfig(BaseModel):
         alias="exclude-platforms",
         description="Platforms to exclude from build/test.",
     )
+    github_stack_behavior: typing.Literal["all", "bottom", "top"] = Field(
+        default="all",
+        alias="github-stack-behavior",
+        description=(
+            "Which PRs in a stack run language_test.yaml: 'all', 'bottom' (lowest unmerged), and 'top'."
+        ),
+    )
     subdir: str | None = Field(
         default=None,
         description="Override the default subdirectory for this language. Use '.' to place files at the repository root.",

adbc_drivers_dev/templates/test.yaml

@@ -94,9 +94,21 @@ permissions:
 <% set has_test_platforms = ["linux_amd64", "macos_arm64", "windows_amd64"] | reject("in", lang_config.exclude_platforms) | list %>
 <% set run_tests = not lang_config.test.skip and has_test_platforms %>
 
+<% set stack_condition = none %>
+<% if not release %>
+<% if lang_config.github_stack_behavior == "bottom" %>
+<% set stack_condition = "github.event_name != 'pull_request' || github.event.pull_request.stack == null || github.event.pull_request.stack.base.ref == github.event.pull_request.base.ref" %>
+<% elif lang_config.github_stack_behavior == "top" %>
+<% set stack_condition = "github.event_name != 'pull_request' || github.event.pull_request.stack == null || github.event.pull_request.stack.position == github.event.pull_request.stack.size" %>
+<% endif %>
+<% endif %>
+
 jobs:
 <% if run_tests %>
   test:
+<% if stack_condition %>
+    if: <{stack_condition}>
+<% endif %>
     name: "Test/${{ matrix.platform }}_${{ matrix.arch }}"
     runs-on: ${{ matrix.runner }}
     strategy:
@@ -344,6 +356,9 @@ jobs:
 
 <% if not lang_config.validation.skip %>
   validate:
+<% if stack_condition %>
+    if: <{stack_condition}>
+<% endif %>
     name: "Validate <{driver}> ${{ matrix.vendor_version }}/${{ matrix.platform }}_${{ matrix.arch }}"
     runs-on: ${{ matrix.runner }}
     strategy:
@@ -579,6 +594,9 @@ jobs:
 <% endif %>
 
   build:
+<% if stack_condition %>
+    if: <{stack_condition}>
+<% endif %>
     name: "Build <{driver}>/${{ matrix.platform }}_${{ matrix.arch }}"
 <% if run_tests %>
     needs: test
@@ -710,6 +728,9 @@ jobs:
           retention-days: 2
 
   package:
+<% if stack_condition %>
+    if: <{stack_condition}>
+<% endif %>
     name: "Generate Packages"
     runs-on: ubuntu-latest
     needs:
@@ -829,6 +850,9 @@ jobs:
 
 <% if has_test_platforms %>
   test-packages:
+<% if stack_condition %>
+    if: <{stack_condition}>
+<% endif %>
     name: "Test Packages/${{ matrix.platform }}_${{ matrix.arch }}"
     runs-on: ${{ matrix.runner }}
     needs:
@@ -934,6 +958,9 @@ jobs:
 <% endif %>
 
   release:
+<% if stack_condition %>
+    if: <{stack_condition}>
+<% endif %>
 <% if release %>
     name: "Release"
 <% else %>

schema/generate-schema.json

@@ -86,6 +86,17 @@
           "title": "Exclude-Platforms",
           "type": "array"
         },
+        "github-stack-behavior": {
+          "default": "all",
+          "description": "Which PRs in a stack run language_test.yaml: 'all', 'bottom' (lowest unmerged), and 'top'.",
+          "enum": [
+            "all",
+            "bottom",
+            "top"
+          ],
+          "title": "Github-Stack-Behavior",
+          "type": "string"
+        },
         "subdir": {
           "anyOf": [
             {

tests/test_workflow.py

@@ -85,6 +85,32 @@ def test_model_custom() -> None:
     assert config != GenerateConfig.model_validate({})
 
 
+def test_github_stack_behavior_default() -> None:
+    assert LangConfig().github_stack_behavior == "all"
+    config = GenerateConfig.model_validate({"lang": {"go": True}})
+    assert config.lang["go"].github_stack_behavior == "all"
+
+
+@pytest.mark.parametrize("behavior", ["all", "bottom", "top"])
+@pytest.mark.parametrize("key", ["github-stack-behavior", "github_stack_behavior"])
+def test_github_stack_behavior(key: str, behavior: str) -> None:
+    config = GenerateConfig.model_validate({"lang": {"go": {key: behavior}}})
+    assert config.lang["go"].github_stack_behavior == behavior
+    assert (
+        config.model_dump(by_alias=True)["lang"]["go"]["github-stack-behavior"]
+        == behavior
+    )
+    assert config.model_dump()["lang"]["go"]["github_stack_behavior"] == behavior
+
+
+@pytest.mark.parametrize("behavior", ["invalid", "TOP", "", None, True, 1])
+def test_github_stack_behavior_invalid(behavior) -> None:
+    with pytest.raises(ValidationError):
+        GenerateConfig.model_validate(
+            {"lang": {"go": {"github-stack-behavior": behavior}}}
+        )
+
+
 def test_params_secrets() -> None:
     config = GenerateConfig.model_validate(
         {