landing_jobs: store commit SHA for each revision/landing job combo (Bug 1995895)

src/lando/api/legacy/workers/landing_worker.py

@@ -141,6 +141,7 @@ def run_job(self, job: LandingJob) -> bool:
             except TemporaryFailureException:
                 return False
 
+        job.set_landed_commit_ids()
         job.transition_status(JobAction.LAND, commit_id=commit_id)
 
         mots_path = Path(repo.path) / "mots.yaml"
@@ -241,6 +242,11 @@ def apply_and_push(
                 raise PermanentFailureException(message) from exc
             else:
                 new_commit = scm.describe_commit()
+
+                # Record the commit ID on the revision object.
+                revision.commit_id = new_commit.hash
+                revision.save()
+
                 logger.debug(f"Created new commit {new_commit}")
 
         # Get the changeset titles for the stack.

src/lando/api/tests/test_landings.py

@@ -16,6 +16,7 @@
     LandingJob,
     Repo,
     Revision,
+    RevisionLandingJob,
 )
 from lando.main.scm import SCM_TYPE_GIT, SCM_TYPE_HG
 from lando.main.scm.exceptions import SCMInternalServerError
@@ -381,6 +382,104 @@ def test_integrated_execute_job(
     assert new_push_count == 1, "Incorrect number of additional pushes in the PushLog"
 
 
+@pytest.mark.parametrize(
+    "repo_type",
+    [
+        SCM_TYPE_GIT,
+        SCM_TYPE_HG,
+    ],
+)
+@pytest.mark.django_db
+def test_revisionlandingjob_commit_ids_updated_on_success(
+    repo_mc,
+    treestatusdouble,
+    mock_phab_trigger_repo_update_apply_async,
+    create_patch_revision,
+    make_landing_job,
+    get_landing_worker,
+    repo_type: str,
+):
+    """Ensure landed commit SHAs are copied onto RevisionLandingJob rows."""
+    repo = repo_mc(repo_type)
+    treestatusdouble.open_tree(repo.name)
+
+    revisions = [
+        create_patch_revision(1, patch=None),
+        create_patch_revision(2, patch=None),
+    ]
+    job_params = {
+        "status": JobStatus.IN_PROGRESS,
+        "requester_email": "test@example.com",
+        "target_repo": repo,
+        "attempts": 1,
+    }
+    job = make_landing_job(revisions=revisions, **job_params)
+
+    worker = get_landing_worker(repo_type)
+    assert worker.run_job(job)
+    assert job.status == JobStatus.LANDED
+
+    revision_jobs = list(
+        RevisionLandingJob.objects.filter(landing_job=job).order_by("index")
+    )
+    assert len(revision_jobs) == len(revisions)
+
+    ordered_revisions = list(job.revisions)
+    for revision, revision_job in zip(ordered_revisions, revision_jobs, strict=False):
+        assert revision.commit_id, "`commit_id` should be set on `Revision` object."
+        assert (
+            revision_job.commit_id
+        ), "`commit_id` should be set on `RevisionLandingJob` object."
+
+
+@pytest.mark.parametrize(
+    "repo_type",
+    [
+        SCM_TYPE_GIT,
+        SCM_TYPE_HG,
+    ],
+)
+@pytest.mark.django_db
+def test_revisionlandingjob_commit_ids_unset_without_landing(
+    repo_mc,
+    treestatusdouble,
+    mock_phab_trigger_repo_update_apply_async,
+    create_patch_revision,
+    make_landing_job,
+    get_landing_worker,
+    repo_type: str,
+):
+    """Ensure `commit_id` is not tracked for incomplete job."""
+    repo = repo_mc(repo_type)
+    treestatusdouble.open_tree(repo.name)
+    scm = repo.scm
+
+    job_params = {
+        "status": JobStatus.IN_PROGRESS,
+        "requester_email": "test@example.com",
+        "target_repo": repo,
+        "attempts": 1,
+    }
+    job = make_landing_job(revisions=[create_patch_revision(1)], **job_params)
+
+    scm.push = mock.MagicMock(side_effect=SCMInternalServerError("push failed", "500"))
+
+    worker = get_landing_worker(repo_type)
+    assert not worker.run_job(job)
+    assert job.status == JobStatus.DEFERRED
+
+    revision_jobs = list(
+        RevisionLandingJob.objects.filter(landing_job=job).order_by("index")
+    )
+    assert len(revision_jobs) == 1
+
+    revision = job.revisions.first()
+    assert revision.commit_id, "`commit_id` should still be set on `Revision` object."
+    assert (
+        revision_jobs[0].commit_id is None
+    ), "`commit_id` should not be set for un-landed job."
+
+
 @pytest.mark.parametrize(
     "repo_type",
     [

src/lando/main/migrations/0032_revisionlandingjob_commit_id.py

@@ -0,0 +1,18 @@
+# Generated by Django 5.2.7 on 2025-10-23 17:57
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("main", "0031_alter_landingjob_requester_email"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="revisionlandingjob",
+            name="commit_id",
+            field=models.CharField(blank=True, max_length=40, null=True),
+        ),
+    ]

src/lando/main/models/landing_job.py

@@ -220,6 +220,14 @@ def set_landed_revision_diffs(self):
                 revision=revision, landing_job=self
             ).update(diff_id=revision.diff_id)
 
+    def set_landed_commit_ids(self):
+        """Assign diff_ids, if available, to each association row."""
+        # Update association table records with current diff_id values.
+        for revision in self.unsorted_revisions.all():
+            RevisionLandingJob.objects.filter(
+                revision=revision, landing_job=self
+            ).update(commit_id=revision.commit_id)
+
     def set_landed_reviewers(self, path: Path):
         """Set approving peers and owners at time of landing."""
         directory = Directory(FileConfig(path))

src/lando/main/models/revision.py

@@ -31,6 +31,9 @@ class RevisionLandingJob(BaseModel):
     # See also: LandingJob.set_landed_revision_diffs, called by transplants.post.
     diff_id = models.IntegerField(null=True, blank=True)
 
+    # The commit ID generated by the landing worker, before pushing to remote repo.
+    commit_id = models.CharField(max_length=40, null=True, blank=True)
+
 
 class Revision(BaseModel):
     """