remove skipped-builds builder

run all of them on the normal build worker. this significantly
simplifies the overall scheduler/builder config and removes a
triplication of possible builds paths.

buildbot_nix/__init__.py

@@ -31,8 +31,6 @@ from .github_projects import (
     slugify_project_name,
 )
 
-SKIPPED_BUILDER_NAME = "skipped-builds"
-
 log = Logger()
 
 class LixSystemsOAuth2(OAuth2Auth):
@@ -57,7 +55,6 @@ class BuildTrigger(Trigger):
     def __init__(
         self,
         builds_scheduler: str,
-        skipped_builds_scheduler: str,
         jobs: list[dict[str, Any]],
         **kwargs: Any,
     ) -> None:
@@ -66,11 +63,10 @@ class BuildTrigger(Trigger):
         self.jobs = jobs
         self.config = None
         self.builds_scheduler = builds_scheduler
-        self.skipped_builds_scheduler = skipped_builds_scheduler
         Trigger.__init__(
             self,
             waitForFinish=True,
-            schedulerNames=[builds_scheduler, skipped_builds_scheduler],
+            schedulerNames=[builds_scheduler],
             haltOnFailure=True,
             flunkOnFailure=True,
             sourceStamps=[],
@@ -99,11 +95,7 @@ class BuildTrigger(Trigger):
 
             if error is not None:
                 props.setProperty("error", error, source)
-                triggered_schedulers.append((self.skipped_builds_scheduler, props))
+                triggered_schedulers.append((self.builds_scheduler, props))
-                continue
-
-            if job.get("isCached"):
-                triggered_schedulers.append((self.skipped_builds_scheduler, props))
                 continue
 
             drv_path = job.get("drvPath")
@@ -117,6 +109,7 @@ class BuildTrigger(Trigger):
             props.setProperty("system", system, source)
             props.setProperty("drv_path", drv_path, source)
             props.setProperty("out_path", out_path, source)
+            props.setProperty("isCached", job.get("isCached"), source)
 
             triggered_schedulers.append((self.builds_scheduler, props))
         return triggered_schedulers
@@ -179,7 +172,6 @@ class NixEvalCommand(buildstep.ShellMixin, steps.BuildStep):
                 [
                     BuildTrigger(
                         builds_scheduler=f"lix-nix-build",
-                        skipped_builds_scheduler=f"lix-nix-skipped-build",
                         name="build flake",
                         jobs=filtered_jobs,
                     ),
@@ -189,19 +181,6 @@ class NixEvalCommand(buildstep.ShellMixin, steps.BuildStep):
         return result
 
 
-class EvalErrorStep(steps.BuildStep):
-    """Shows the error message of a failed evaluation."""
-
-    @defer.inlineCallbacks
-    def run(self) -> Generator[Any, object, Any]:
-        error = self.getProperty("error")
-        attr = self.getProperty("attr")
-        # show eval error
-        error_log: Log = yield self.addLog("nix_error")
-        error_log.addStderr(f"{attr} failed to evaluate:\n{error}")
-        return util.FAILURE
-
-
 class NixBuildCommand(buildstep.ShellMixin, steps.BuildStep):
     """Builds a nix derivation."""
 
@@ -211,6 +190,20 @@ class NixBuildCommand(buildstep.ShellMixin, steps.BuildStep):
 
     @defer.inlineCallbacks
     def run(self) -> Generator[Any, object, Any]:
+        if error := self.getProperty("error"):
+            attr = self.getProperty("attr")
+            # show eval error
+            error_log: Log = yield self.addLog("nix_error")
+            error_log.addStderr(f"{attr} failed to evaluate:\n{error}")
+            return util.FAILURE
+
+        if self.getProperty("isCached"):
+            yield self.addCompleteLog(
+                "cached outpath from previous builds",
+                # buildbot apparently hides the first line in the ui?
+                f'\n{self.getProperty("out_path")}\n')
+            return util.SKIPPED
+
         # run `nix build`
         cmd: remotecommand.RemoteCommand = yield self.makeRemoteShellCommand()
         yield self.runCommand(cmd)
@@ -390,38 +383,6 @@ def nix_build_config(
     )
 
 
-def nix_skipped_build_config(
-    project: GerritProject,
-    worker_names: list[str],
-) -> util.BuilderConfig:
-    """Dummy builder that is triggered when a build is skipped."""
-    factory = util.BuildFactory()
-    factory.addStep(
-        EvalErrorStep(
-            name="Nix evaluation",
-            doStepIf=lambda s: s.getProperty("error"),
-            hideStepIf=lambda _, s: not s.getProperty("error"),
-        ),
-    )
-
-    # This is just a dummy step showing the cached build
-    factory.addStep(
-        steps.BuildStep(
-            name="Nix build (cached)",
-            doStepIf=lambda _: False,
-            hideStepIf=lambda _, s: s.getProperty("error"),
-        ),
-    )
-    return util.BuilderConfig(
-        name=f"{project.name}/nix-skipped-build",
-        project=project.name,
-        workernames=worker_names,
-        collapseRequests=False,
-        env={},
-        factory=factory,
-    )
-
-
 def read_secret_file(secret_name: str) -> str:
     directory = os.environ.get("CREDENTIALS_DIRECTORY")
     if directory is None:
@@ -458,11 +419,6 @@ def config_for_project(
                 name=f"{project.name}-nix-build",
                 builderNames=[f"{project.name}/nix-build"],
             ),
-            # this is triggered from `nix-eval` when the build is skipped
-            schedulers.Triggerable(
-                name=f"{project.name}-nix-skipped-build",
-                builderNames=[f"{project.name}/nix-skipped-build"],
-            ),
             # allow to manually trigger a nix-build
             schedulers.ForceScheduler(
                 name=f"{project.name}-force",
@@ -502,7 +458,6 @@ def config_for_project(
                 worker_names,
                 outputs_path=outputs_path,
             ),
-            nix_skipped_build_config(project, [SKIPPED_BUILDER_NAME]),
         ],
     )
 
@@ -688,7 +643,6 @@ class GerritNixConfigurator(ConfiguratorBase):
         )
 
         config["change_source"] = self.gerrit_change_source
-        config["workers"].append(worker.LocalWorker(SKIPPED_BUILDER_NAME))
         config["services"].append(
             reporters.GerritStatusPush(self.gerrit_server, self.gerrit_user,
                                        port=2022,