remove retry logic

retries don't help us very much, in fact they mostly hurt by repeating
builds that failed for non-transient reasons. retries could help with
workers dropping while running a build, but those rare cases are better
to restart manually than to pend at least twice the ci time for commits
that simply do not build cleanly.

buildbot_nix/__init__.py

@@ -192,24 +192,6 @@ class NixEvalCommand(buildstep.ShellMixin, steps.BuildStep):
         return result
 
 
-# FIXME this leaks memory... but probably not enough that we care
-class RetryCounter:
-    def __init__(self, retries: int) -> None:
-        self.builds: dict[uuid.UUID, int] = defaultdict(lambda: retries)
-
-    def retry_build(self, build_id: uuid.UUID) -> int:
-        retries = self.builds[build_id]
-        if retries > 1:
-            self.builds[build_id] = retries - 1
-            return retries
-        return 0
-
-
-# For now we limit this to two. Often this allows us to make the error log
-# shorter because we won't see the logs for all previous succeeded builds
-RETRY_COUNTER = RetryCounter(retries=2)
-
-
 class EvalErrorStep(steps.BuildStep):
     """Shows the error message of a failed evaluation."""
 
@@ -236,12 +218,7 @@ class NixBuildCommand(buildstep.ShellMixin, steps.BuildStep):
         cmd: remotecommand.RemoteCommand = yield self.makeRemoteShellCommand()
         yield self.runCommand(cmd)
 
-        res = cmd.results()
-        if res == util.FAILURE:
-            retries = RETRY_COUNTER.retry_build(self.getProperty("build_uuid"))
-            if retries > 0:
-                return util.RETRY
-        return res
+        return cmd.results()
 
 
 class UpdateBuildOutput(steps.BuildStep):