stonebig · Oct 29, 2026 · Oct 29, 2026 · Oct 29, 2026
diff --git a/.github/actions/publish-winpython/action.yml b/.github/actions/publish-winpython/action.yml
@@ -94,11 +94,15 @@ runs:
             Compress-Archive -Path "${{ inputs.build_location }}" -DestinationPath "$baseName.zip" -Force
         }
         if ("${{ inputs.format_7z }}" -eq "true") { 
-            7z a -mx7 "$baseName.7z" "${{ inputs.build_location }}"
+            7z a -mx9 "$baseName.7z" "${{ inputs.build_location }}"
         }
-        if ("${{ inputs.format_exe }}" -eq "true") { 
+        if ("${{ inputs.format_exe }}" -eq "true") {
             $SFXModulePath = "C:\Program Files\7-Zip\7z.sfx"
-            7z a -mx7 -t7z -sfx"$SFXModulePath" "$baseName.exe" "${{ inputs.build_location }}"
+            7z a -mx9 -t7z -sfx"$SFXModulePath" "$baseName.exe" "${{ inputs.build_location }}"
+        }
+        # VirusTotal refuses uploads over 650 MB
+        Get-ChildItem "$baseName.*" | Where-Object Length -gt 650MB | ForEach-Object {
+            Write-Output "::warning::$($_.Name) is $([math]::Round($_.Length / 1MB)) MB, over the VirusTotal 650 MB limit"
         }
 
     - name: Generate Hashes

diff --git a/.github/scripts/cycle_config.py b/.github/scripts/cycle_config.py
@@ -2,6 +2,7 @@
 
     python .github/scripts/cycle_config.py cycles/2026_04.toml all
     python .github/scripts/cycle_config.py cycles/2026_04.toml 3.14
+    python .github/scripts/cycle_config.py cycles/2026_04.toml all slim,slimf
 
 Writes to $GITHUB_OUTPUT when set, otherwise stdout, so it can be run locally
 to see exactly what a workflow run would get. tomllib is stdlib from 3.11, and
@@ -154,8 +155,28 @@ def release_title(cfg: dict, cycle_name: str, today: datetime.date | None = None
     return f"WinPython {name} of {today:%B} {ordinal(today.day)} {today.year}"
 
 
-def build_config(cfg: dict, requested: str, cycle_name: str) -> dict:
+def wanted_flavors(cfg: dict, flavors: str) -> set[str] | None:
+    """The flavor names a comma-separated input asks for; None means all.
+
+    A typo would otherwise filter everything out, or quietly build less than
+    asked, so a name the cycle does not declare is refused.
+    """
+    if flavors.strip() in ("", "all"):
+        return None
+    names = {name.strip() for name in flavors.split(",") if name.strip()}
+    declared = {flavor["name"] for flavor in cfg["flavors"]}
+    unknown = names - declared
+    if unknown:
+        raise SystemExit(
+            f"unknown flavor {', '.join(sorted(unknown))}; this cycle declares "
+            f"{', '.join(sorted(declared))} (or 'all')"
+        )
+    return names
+
+
+def build_config(cfg: dict, requested: str, cycle_name: str, flavors: str = "all") -> dict:
     pythons = cfg["pythons"]
+    only = wanted_flavors(cfg, flavors)
     if requested == "all":
         wanted = list(pythons)
     elif requested in pythons:
@@ -167,6 +188,10 @@ def build_config(cfg: dict, requested: str, cycle_name: str) -> dict:
         )
 
     legs = [leg for python in wanted for leg in legs_for(cfg, python)]
+    if only is not None:
+        legs = [leg for leg in legs if leg["name"] in only]
+    if not legs and only is not None:
+        raise SystemExit(f"{requested}: none of {flavors} can be built for this Python")
     if not legs:
         missing = ", ".join(
             f"pylock.64-{pythons[p]['ver2'].replace('.', '_')}<flavor>"
@@ -191,15 +216,15 @@ def build_config(cfg: dict, requested: str, cycle_name: str) -> dict:
 
 
 def main(argv: list[str]) -> None:
-    if len(argv) != 3:
-        raise SystemExit(f"usage: {Path(argv[0]).name} <cycle.toml> <python_version|all>")
+    if len(argv) not in (3, 4):
+        raise SystemExit(f"usage: {Path(argv[0]).name} <cycle.toml> <python_version|all> [flavors|all]")
     cfg_path = Path(argv[1])
     if not cfg_path.is_file():
         raise SystemExit(f"no such cycle file: {cfg_path}")
     with cfg_path.open("rb") as fh:
         cfg = tomllib.load(fh)
 
-    config = build_config(cfg, argv[2], cfg_path.stem)
+    config = build_config(cfg, argv[2], cfg_path.stem, argv[3] if len(argv) == 4 else "all")
     rendered = "".join(f"{k}={v}\n" for k, v in config.items())
     out = os.environ.get("GITHUB_OUTPUT")
     if out:

diff --git a/.github/workflows/build_winpython_cycle.yml b/.github/workflows/build_winpython_cycle.yml
@@ -29,6 +29,11 @@ on:
           - '3.14F'
           - '3.15'
           - '3.15F'
+      flavors:
+        description: 'Flavors to build, comma-separated (e.g. slim,slimf); "all" builds every one'
+        required: true
+        default: 'all'
+        type: string
       publish:
         description: 'Upload to the draft release the cycle file names; off keeps the output as artifacts'
         required: false
@@ -69,7 +74,8 @@ jobs:
         env:
           CYCLE: ${{ inputs.cycle }}
           PYTHON_VERSIONF: ${{ inputs.python_versionf }}
-        run: python .github/scripts/cycle_config.py "cycles/$CYCLE.toml" "$PYTHON_VERSIONF"
+          FLAVORS: ${{ inputs.flavors }}
+        run: python .github/scripts/cycle_config.py "cycles/$CYCLE.toml" "$PYTHON_VERSIONF" "$FLAVORS"
 
   release-draft:
     # one job opens the draft, so the build legs cannot race to create it
@@ -232,7 +238,7 @@ jobs:
     # same lockfile produces the same package list, so a rebuilt leg cannot
     # change a changelog.
     needs: [config, build-winpython]
-    if: ${{ inputs.publish && inputs.python_versionf == 'all' }}
+    if: ${{ inputs.publish && inputs.python_versionf == 'all' && inputs.flavors == 'all' }}
     runs-on: ubuntu-latest
     permissions:
       contents: write

diff --git a/tests/test_cycle_config.py b/tests/test_cycle_config.py
@@ -152,6 +152,39 @@ def test_every_python_can_be_dispatched_on_its_own(self, cycle_file, workflow_te
         assert pythons <= offered, f"{cycle_file.stem} offers {pythons - offered}, the workflow does not"
 
 
+@needs_script
+@needs_cycles
+@pytest.mark.parametrize("cycle_file", cycle_files, ids=lambda p: p.stem)
+class TestFlavorFilter:
+    """Re-running only some flavors, e.g. slim after a size fix."""
+
+    def test_all_is_no_filter(self, cycle_config, at_repo_root, cycle_file):
+        everything = legs_of(config_for(cycle_config, cycle_file))
+        import tomllib
+
+        with cycle_file.open("rb") as fh:
+            cfg = tomllib.load(fh)
+        assert legs_of(cycle_config.build_config(cfg, "all", cycle_file.stem, "all")) == everything
+
+    def test_keeps_only_the_named_flavors(self, cycle_config, at_repo_root, cycle_file):
+        import tomllib
+
+        with cycle_file.open("rb") as fh:
+            cfg = tomllib.load(fh)
+        built = {leg["name"] for leg in legs_of(config_for(cycle_config, cycle_file))}
+        some = sorted(built)[:2]
+        legs = legs_of(cycle_config.build_config(cfg, "all", cycle_file.stem, ", ".join(some)))
+        assert legs and {leg["name"] for leg in legs} == set(some)
+
+    def test_an_unknown_flavor_is_refused(self, cycle_config, at_repo_root, cycle_file):
+        import tomllib
+
+        with cycle_file.open("rb") as fh:
+            cfg = tomllib.load(fh)
+        with pytest.raises(SystemExit):
+            cycle_config.build_config(cfg, "all", cycle_file.stem, "slimm")
+
+
 @needs_script
 class TestReleaseTag:
     """The tag is what the download URLs the website publishes are built on."""
@@ -314,7 +347,10 @@ def test_the_changelog_pr_is_whole_cycle_only(self, workflow_text):
         It has nothing to add either way: the same lockfile builds the same
         package list, so a rebuilt leg cannot change a changelog.
         """
-        assert "if: ${{ inputs.publish && inputs.python_versionf == 'all' }}" in workflow_text
+        assert (
+            "if: ${{ inputs.publish && inputs.python_versionf == 'all' && inputs.flavors == 'all' }}"
+            in workflow_text
+        )
         assert ".github/scripts/changelog_files.py release_metadata changelogs" in workflow_text
         assert (REPO / ".github/scripts/changelog_files.py").is_file()