buildkite: eliminate initial_steps

The point of these is to run in parallel with the compilation steps, and
not block the wait step if they fail. However, since we use `depends_on:
null` for these, it doesn't matter whether they are initial or not, so
just add them via `add_step` with `decorate=False`, as we do for normal
steps.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

.buildkite/common.py

@@ -233,7 +233,7 @@ class BKPipeline:
 
     parser = COMMON_PARSER
 
-    def __init__(self, initial_steps=None, with_build_step=True, **kwargs):
+    def __init__(self, with_build_step=True, **kwargs):
         self.steps = []
         self.args = args = self.parser.parse_args()
         # Retry one time if agent was lost. This can happen if we terminate the
@@ -263,18 +263,6 @@ def __init__(self, initial_steps=None, with_build_step=True, **kwargs):
         else:
             self.shared_build = None
 
-        # If we run initial_steps before the "wait" step above, then a failure of the initial steps
-        # would result in the build not progressing past the "wait" step (as buildkite only proceeds past a wait step
-        # if everything before it passed). Thus put the initial steps after the "wait" step, but set `"depends_on": null`
-        # to start running them immediately (e.g. without waiting for the "wait" step to unblock).
-        #
-        # See also https://buildkite.com/docs/pipelines/dependencies#explicit-dependencies-in-uploaded-steps
-        if initial_steps:
-            for step in initial_steps:
-                step["depends_on"] = None
-
-            self.steps += initial_steps
-
     def add_step(self, step, decorate=True):
         """
         Add a step to the pipeline.

.buildkite/pipeline_pr.py

@@ -21,15 +21,18 @@
 pipeline = BKPipeline(
     priority=DEFAULT_PRIORITY,
     timeout_in_minutes=45,
-    initial_steps=[
-        {
-            "command": "./tools/devtool -y checkstyle",
-            "label": "🪶 Style",
-        },
-    ],
     with_build_step=not DOC_ONLY_CHANGE,
 )
 
+pipeline.add_step(
+    {
+        "command": "./tools/devtool -y checkstyle",
+        "label": "🪶 Style",
+        "depends_on": None,
+    },
+    decorate=False,
+)
+
 # run sanity build of devtool if Dockerfile is changed
 if any(x.parent.name == "devctr" for x in changed_files):
     pipeline.build_group_per_arch(