roll_commenter: Add logging to revision logic

Bug: b/525381446
Change-Id: I90e3a3db0099a37e66df1d84ec8f3db2a41adf84
Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/424992

recipes/roll_commenter.py

diff --git a/recipes/roll_commenter.py b/recipes/roll_commenter.py
index a586b21..640ae87 100644
--- a/recipes/roll_commenter.py
+++ b/recipes/roll_commenter.py
@@ -148,7 +148,8 @@
     build: build_pb.Build,
 ) -> str | None:
     if build.status != common_pb.SUCCESS:
-        return
+        api.step.empty('build not successful')
+        return None
 
     input_props = json_format.MessageToDict(build.input.properties) or {}
     er_input = input_props.get('checkout_options', {}).get(
@@ -165,7 +166,8 @@
             continue  # pragma: no cover
 
         if roll.get('dry_run', True):
-            return
+            api.step.empty('dry run')
+            return None
 
     for _, value in output_props.items():
         if not isinstance(value, Mapping):
@@ -178,20 +180,28 @@
                 value['remote'],
             ):
                 if 'revision' in value:
+                    api.step.empty(f'found revision {value["revision"]}')
                     return value['revision']
+                api.step.empty(f'found new revision {value["new"]}')
                 return value['new']
 
+    api.step.empty('no matching revision')
+    return None
+
 
 def _get_current_revision(
     api: recipe_api.RecipeScriptApi,
     remote: str,
     builds: Sequence[build_pb.Build],
 ) -> str | None:
-    for build in builds:
-        if res := _get_revision_from_build(api, remote, build):
-            return res
+    with api.step.nest('get current revision'):
+        for build in builds:
+            api.step.empty(f'checking build {build.id}')
+            if res := _get_revision_from_build(api, remote, build):
+                return res
 
-    return None
+        api.step.empty('no revision found')
+        return None
 
 
 class State(TypedDict):
@@ -874,12 +884,19 @@
         return result
 
     def passed(
-        *, n: int, dry_run: bool = False, **kwargs: Any
+        *,
+        n: int,
+        dry_run: bool = False,
+        wrong_remote: bool = False,
+        **kwargs: Any,
     ) -> build_pb.Build:
         build = api.builder_status.passed(**kwargs)
         key = 'new' if n % 2 else 'revision'
+        remote = (
+            'https://wrong.git' if wrong_remote else api.checkout.pigweed_repo
+        )
         build.output.properties['pigweed'] = {
-            'remote': api.checkout.pigweed_repo,
+            'remote': remote,
             key: commit40(n),
         }
         build.output.properties['gerrit_changes'] = [
@@ -1274,3 +1291,16 @@
         ),
         drop_expectations_must_be_last(),
     )
+
+    yield api.test(
+        'wrong_remote',
+        checkout_options(),
+        roller_props('foo-roller', 'bar-roller'),
+        api.checkout.ci_test_data(),
+        state_in(last=12, warned=(), foo_roller=12, bar_roller=12),
+        results('foo-roller', passed(id=88001, n=12, wrong_remote=True)),
+        results('bar-roller', passed(id=88002, n=12)),
+        skipping('foo-roller'),
+        state_out(last=12, bar_roller=12),
+        drop_expectations_must_be_last(),
+    )