Merge "Handle dependency limit errors more gracefully"

tests/fixtures/config/single-tenant/git/org_project4/README

@@ -0,0 +1 @@
+test

tests/fixtures/config/single-tenant/git/org_project4/zuul.yaml

@@ -0,0 +1,26 @@
+- queue:
+    name: integrated-topic
+    allow-circular-dependencies: True
+    dependencies-by-topic: True
+
+- project:
+    queue: integrated-topic
+    check:
+      jobs:
+        - project-merge
+        - project-test1:
+            dependencies: project-merge
+        - project-test2:
+            dependencies: project-merge
+    gate:
+      jobs:
+        - project-merge
+        - project-test1:
+            dependencies: project-merge
+        - project-test2:
+            dependencies: project-merge
+        - project-testfile:
+            dependencies: project-merge
+    post:
+      jobs:
+        - project-post

tests/fixtures/config/single-tenant/main-max-deps.yaml

@@ -9,3 +9,4 @@
           - org/project
           - org/project1
           - org/project2
+          - org/project4

tests/unit/test_v3.py

@@ -9869,3 +9869,29 @@ class TestMaxDeps(ZuulTestCase):
             dict(name='project-test1', result='SUCCESS', changes='1,1 2,1'),
             dict(name='project-test2', result='SUCCESS', changes='1,1 2,1'),
         ], ordered=False)
+
+    def test_max_deps_extended(self):
+        self.executor_server.hold_jobs_in_build = True
+        # max_dependencies for the connection is 1, so this is okay
+        A = self.fake_gerrit.addFakeChange('org/project4', 'master', 'A')
+        B = self.fake_gerrit.addFakeChange('org/project4', 'master', 'B',
+                                           topic='test-topic')
+        B.setDependsOn(A, 1)
+
+        self.fake_gerrit.addEvent(B.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+
+        # Increase the number of dependencies for B by adding a
+        # change with the same topic (dependencies-by-topic is enabled).
+        # With this C should not be enqueued and A is removed.
+        C = self.fake_gerrit.addFakeChange('org/project4', 'master', 'C',
+                                           topic='test-topic')
+        self.fake_gerrit.addEvent(C.getPatchsetCreatedEvent(1))
+
+        self.executor_server.hold_jobs_in_build = True
+        self.executor_server.release()
+        self.waitUntilSettled()
+
+        self.assertHistory([
+            dict(name='project-merge', result='SUCCESS', changes='1,1 2,1'),
+        ], ordered=False)

zuul/exceptions.py

@@ -50,6 +50,10 @@ class StreamingError(Exception):
     pass
 
 
+class DependencyLimitExceededError(Exception):
+    pass
+
+
 # Authentication Exceptions
 
 class AuthTokenException(Exception):

zuul/manager/__init__.py

@@ -596,8 +596,11 @@ class PipelineManager(metaclass=ABCMeta):
                       change, self.pipeline)
             return False
 
-        self.getDependencyGraph(change, dependency_graph, event,
-                                update_deps=True)
+        try:
+            self.getDependencyGraph(change, dependency_graph, event,
+                                    update_deps=True)
+        except exceptions.DependencyLimitExceededError:
+            return False
 
         with self.getChangeQueue(change, event, change_queue) as change_queue:
             if not change_queue:
@@ -808,9 +811,10 @@ class PipelineManager(metaclass=ABCMeta):
             if (self.pipeline.tenant.max_dependencies is not None and
                 (len(dependency_graph) >
                  self.pipeline.tenant.max_dependencies)):
-                log.debug("%sDependency graph for change %s is too large",
-                          indent, change)
-                raise Exception("Dependency graph is too large")
+                log.info("%sDependency graph for change %s is too large",
+                         indent, change)
+                raise exceptions.DependencyLimitExceededError(
+                    "Dependency graph is too large")
 
             node = dependency_graph.setdefault(change, [])
             if needed_change not in node:
@@ -1619,8 +1623,12 @@ class PipelineManager(metaclass=ABCMeta):
 
         meets_reqs = self.areChangesReadyToBeEnqueued(item.changes, item.event)
         dependency_graph = collections.OrderedDict()
-        self.getDependencyGraph(item.changes[0], dependency_graph, item.event,
-                                quiet=True)
+        try:
+            self.getDependencyGraph(item.changes[0], dependency_graph,
+                                    item.event, quiet=True)
+        except exceptions.DependencyLimitExceededError:
+            self.removeItem(item)
+            return True, nnfi
 
         # Verify that the cycle dependency graph is correct
         cycle = self.cycleForChange(