Use a (smart) set of branches for branch selection (GH-752)

Co-authored-by: Zachary Ware <zachary.ware@gmail.com>

Author: encukou

master/custom/branches.py

@@ -14,6 +14,7 @@
 
 """
 
+import collections.abc
 import dataclasses
 from functools import total_ordering
 from typing import Any
@@ -64,13 +65,6 @@ def _maintenance_branch(major, minor, **kwargs):
         # need more time.
         result.monolithic_test_asyncio = True
 
-    if version_tuple < (3, 11):
-        # WASM wasn't a supported platform until 3.11.
-        result.wasm_tier = None
-    elif version_tuple < (3, 13):
-        # Tier 3 support is 3.11 & 3.12.
-        result.wasm_tier = 3
-
     if version_tuple < (3, 13):
         # Free-threaded builds are available since 3.13
         result.gil_only = True
@@ -96,7 +90,6 @@ class BranchInfo:
     # Defaults are for main (and PR), overrides are in _maintenance_branch.
     gil_only: bool = False
     monolithic_test_asyncio: bool = False
-    wasm_tier: int | None = 2
 
     def __str__(self):
         return self.name
@@ -108,6 +101,9 @@ def __eq__(self, other):
             return NotImplemented
         return self.sort_key == other.sort_key
 
+    def __hash__(self):
+        return hash(self.sort_key)
+
     def __lt__(self, other):
         try:
             other_key = other.sort_key
@@ -116,15 +112,58 @@ def __lt__(self, other):
         return self.sort_key < other.sort_key
 
 
-BRANCHES = list(generate_branches())
+class BranchSet(collections.abc.Set):
+    """An immutable set of BranchInfo objects, with some convenience API"""
+
+    def __init__(self, branches):
+        self._branches = tuple(branches)
+
+    def __iter__(self):
+        return iter(self._branches)
+
+    def __len__(self):
+        return len(self._branches)
+
+    def __contains__(self, element):
+        return element in self._branches
+
+    def __getitem__(self, version_tuple):
+        """branchset[3, x] -> BranchInfo for 3.x"""
+        for branch in self._branches:
+            if branch.version_tuple == version_tuple:
+                return branch
+        raise LookupError(f'version {version_tuple} not found')
+
+    def only_since(self, major, minor, include_pr=True):
+        """only_since(3, x) -> BranchSet with 3.x and later"""
+        return BranchSet(
+            b for b in self._branches if (
+                include_pr if b.is_pr
+                else b.version_tuple >= (major, minor)
+            )
+        )
+
+    def only_until(self, major, minor, include_pr=False):
+        """only_since(3, x) -> BranchSet with up to (and including) 3.x"""
+        return BranchSet(
+            b for b in self._branches if (
+                include_pr if b.is_pr
+                else b.version_tuple <= (major, minor)
+            )
+        )
+
+
+BRANCHES = BranchSet(generate_branches())
+[MAIN_BRANCH] = [b for b in BRANCHES if b.is_main]
+[PR_BRANCH] = [b for b in BRANCHES if b.is_pr]
 
-# Verify that we've defined these in sort order
-assert BRANCHES == sorted(BRANCHES)
+# Verify that the (sort) keys are distinct
+assert len(set(BRANCHES)) == len(list(BRANCHES))
 
 if __name__ == "__main__":
     # Print a table to the terminal
     cols = [[f.name + ':' for f in dataclasses.fields(BranchInfo)]]
-    for branch in BRANCHES:
+    for branch in sorted(BRANCHES):
         cols.append([repr(val) for val in dataclasses.astuple(branch)])
     column_sizes = [max(len(val) for val in col) for col in cols]
     column_sizes[-2] += 2  # PR is special, offset it a bit

master/custom/builders.py

@@ -4,6 +4,7 @@
 from functools import cached_property
 
 from custom import factories
+from custom.branches import BRANCHES, MAIN_BRANCH, PR_BRANCH
 from custom.factories import (
     UnixBuild,
     UnixPerfBuild,
@@ -90,11 +91,18 @@ class BuilderDef:
     tags: frozenset[str]
     worker_name: str
 
-    def __init__(self, name, factory, *, tags, worker_name):
+    def __init__(
+        self, name, factory,
+        *,
+        tags,
+        worker_name,
+        branches=BRANCHES,
+    ):
         self.name = name
         self.factory = factory
         self.worker_name = worker_name
         self.tags = frozenset(tags)
+        self.branches = branches
 
     @cached_property
     def tier(self):
@@ -146,13 +154,23 @@ def get_tier_from_tags(tags):
         factories.Windows64PGOBuild,
         tags={STABLE, TIER_1},
         worker_name="bolen-windows10",
+        branches={MAIN_BRANCH, PR_BRANCH},
     ),
 ]
 
-def generate_builderdefs(tags, tuples):
+def generate_builderdefs(tags, entries):
     tags = frozenset(tags)
-    for name, worker_name, factory in tuples:
-        yield BuilderDef(name, factory, tags=tags, worker_name=worker_name)
+    for entry in entries:
+        if isinstance(entry, BuilderDef):
+            if not (entry.tags <= tags):
+                raise ValueError(
+                    f'{entry} is in the wrong generate_builderdefs call; '
+                    + 'move it to the main BUILDER_DEFS list above',
+                )
+            yield entry
+        else:
+            name, worker_name, factory = entry
+            yield BuilderDef(name, factory, tags=tags, worker_name=worker_name)
 
 
 # -- Stable Tier-1 builder ----------------------------------------------
@@ -181,9 +199,27 @@ def generate_builderdefs(tags, tuples):
     ("AMD64 Windows11 Non-Debug", "ware-win11", Windows64ReleaseBuild),
     ("AMD64 Windows11 Refleaks", "ware-win11", Windows64RefleakBuild),
     ("AMD64 Windows Server 2022 NoGIL", "itamaro-win64-srv-22-aws", Windows64NoGilBuild),
-    ("AMD64 Windows PGO Tailcall", "itamaro-win64-srv-22-aws", Windows64PGOTailcallBuild),
-    ("AMD64 Windows PGO NoGIL", "itamaro-win64-srv-22-aws", Windows64PGONoGilBuild),
-    ("AMD64 Windows PGO NoGIL Tailcall", "itamaro-win64-srv-22-aws", Windows64PGONoGilTailcallBuild),
+    BuilderDef(
+        "AMD64 Windows PGO Tailcall",
+        Windows64PGOTailcallBuild,
+        tags={STABLE, TIER_1},
+        worker_name="itamaro-win64-srv-22-aws",
+        branches={MAIN_BRANCH, PR_BRANCH},
+    ),
+    BuilderDef(
+        "AMD64 Windows PGO NoGIL",
+        Windows64PGONoGilBuild,
+        tags={STABLE, TIER_1},
+        worker_name="itamaro-win64-srv-22-aws",
+        branches={MAIN_BRANCH, PR_BRANCH},
+    ),
+    BuilderDef(
+        "AMD64 Windows PGO NoGIL Tailcall",
+        Windows64PGONoGilTailcallBuild,
+        tags={STABLE, TIER_1},
+        worker_name="itamaro-win64-srv-22-aws",
+        branches={MAIN_BRANCH, PR_BRANCH},
+    ),
 ]))
 
 
@@ -310,7 +346,13 @@ def generate_builderdefs(tags, tuples):
     ("AMD64 Arch Linux Asan", "pablogsal-arch-x86_64", UnixAsanBuild),
     ("AMD64 Arch Linux Asan Debug", "pablogsal-arch-x86_64", UnixAsanDebugBuild),
     ("AMD64 Arch Linux TraceRefs", "pablogsal-arch-x86_64", UnixTraceRefsBuild),
-    ("AMD64 Arch Linux Perf", "pablogsal-arch-x86_64", UnixPerfBuild),
+    BuilderDef(
+        "AMD64 Arch Linux Perf",
+        UnixPerfBuild,
+        tags={STABLE},
+        worker_name="pablogsal-arch-x86_64",
+        branches={MAIN_BRANCH, PR_BRANCH},
+    ),
     # UBSAN with -fno-sanitize=function, without which we currently fail (as
     #  tracked in gh-111178). The full "AMD64 Arch Linux Usan" is unstable, below
     ("AMD64 Arch Linux Usan Function", "pablogsal-arch-x86_64", ClangUbsanFunctionLinuxBuild),
@@ -345,7 +387,13 @@ def generate_builderdefs(tags, tuples):
     ("AMD64 CentOS9 FIPS Only Blake2 Builtin Hash", "cstratak-CentOS9-fips-x86_64", CentOS9NoBuiltinHashesUnixBuildExceptBlake2),
     ("AMD64 CentOS9 FIPS No Builtin Hashes", "cstratak-CentOS9-fips-x86_64", CentOS9NoBuiltinHashesUnixBuild),
 
-    ("AMD64 Arch Linux Valgrind", "pablogsal-arch-x86_64", ValgrindBuild),
+    BuilderDef(
+        "AMD64 Arch Linux Valgrind",
+        ValgrindBuild,
+        tags={UNSTABLE, TIER_1},
+        worker_name="pablogsal-arch-x86_64",
+        branches={MAIN_BRANCH, PR_BRANCH},
+    ),
 ]))
 
 
@@ -467,15 +515,6 @@ def get_builder_defs(settings):
     return BUILDER_DEFS
 
 
-# Match builder name (excluding the branch name) of builders that should only
-# run on the main and PR branches.
-ONLY_MAIN_BRANCH = (
-    "Windows PGO",
-    "AMD64 Arch Linux Perf",
-    "AMD64 Arch Linux Valgrind",
-)
-
-
 if __name__ == "__main__":
     # Print a list to the terminal
     import itertools
@@ -499,3 +538,6 @@ def key(builder_def):
             print(f'{NAME}{d.name}{END}')
             print(f'  {d.factory.__name__} on {d.worker_name}')
             print(f'  [{' '.join(sorted(d.tags))}]')
+            if d.branches != BRANCHES:
+                branchnames = ', '.join(b.name for b in sorted(d.branches))
+                print(f'  branches: {branchnames}')

master/custom/factories.py

@@ -10,6 +10,7 @@
 from buildbot.plugins import util
 
 from . import JUNIT_FILENAME
+from .branches import BRANCHES
 from .steps import (
     Test,
     Clean,
@@ -57,6 +58,7 @@ class BaseBuild(factory.BuildFactory):
     test_timeout = TEST_TIMEOUT
     buildersuffix = ""
     tags = ()
+    branches = BRANCHES
 
     def __init__(self, source, *, extra_tags=[], **kwargs):
         super().__init__([source])
@@ -920,6 +922,9 @@ class Wasm32WasiCrossBuild(UnixCrossBuild):
     host = "wasm32-unknown-wasi"
     host_configure_cmd = ["../../Tools/wasm/wasi-env", "../../configure"]
 
+    # See comment in _Wasm32WasiPreview1Build.__init__
+    branches = {BRANCHES[3, 11], BRANCHES[3, 12]}
+
     def setup(self, branch, worker, test_with_PTY=False, **kwargs):
         self.addStep(
             SetPropertyFromCommand(
@@ -956,6 +961,14 @@ def __init__(self, source, *, extra_tags=[], **kwargs):
         if not self.pydebug:
             extra_tags.append("nondebug")
         self.buildersuffix += self.append_suffix
+        if self.pydebug:
+            # The debug WASI buildbot is meant for 3.11 and 3.12 only.
+            # Don't use it on PRs; it's tier 3 only and getting it to
+            # work on PRs against `main` is too much work.
+            self.branches = {BRANCHES[3, 11], BRANCHES[3, 12]}
+        else:
+            # The non-debug buildbot is meant for 3.13+, where WASM is tier 2
+            self.branches = BRANCHES.only_since(3, 13)
         super().__init__(source, extra_tags=extra_tags, **kwargs)
 
     def setup(self, branch, worker, test_with_PTY=False, **kwargs):