Feature/support prior return value in when clause

cumulusci/core/flowrunner.py

@@ -53,6 +53,7 @@
 
 import copy
 import logging
+import re
 from collections import defaultdict
 from operator import attrgetter
 from typing import (
@@ -85,6 +86,7 @@
 
 
 RETURN_VALUE_OPTION_PREFIX = "^^"
+RETURN_VALUE_SUBS_RE = re.compile(r"\^\^\S+")
 
 jinja2_env = ImmutableSandboxedEnvironment()
 
@@ -508,6 +510,15 @@ def _run_step(self, step: StepSpec):
             return
 
         if step.when:
+
+            ### get prior return values
+            prior_return_values = RETURN_VALUE_SUBS_RE.findall(step.when)
+            if prior_return_values is not None:
+                for value in prior_return_values:
+                    path, name = value[len(RETURN_VALUE_OPTION_PREFIX) :].rsplit(".", 1)
+                    result = self._find_result_by_path(path)
+                    step.when = step.when.replace(value, result.return_values.get(name))
+
             jinja2_context = {
                 "project_config": step.project_config,
                 "org_config": self.org_config,

cumulusci/core/tests/test_flowrunner.py

@@ -52,6 +52,13 @@ def _run_task(self):
         raise self.options["exception"](self.options["message"])
 
 
+class _TaskReturnsBoolStr(BaseTask):
+    task_options = {"flag": {"description": "String value to store in return_values"}}
+
+    def _run_task(self):
+        self.return_values = {"flag": self.options.get("flag", "True")}
+
+
 class _SfdcTask(BaseTask):
     salesforce_task = True
 
@@ -121,6 +128,10 @@ def _setup_project_config(self):
                 "description": "An sfdc task",
                 "class_path": "cumulusci.core.tests.test_flowrunner._SfdcTask",
             },
+            "return_bool": {
+                "description": "Returns a configurable string flag in return_values",
+                "class_path": "cumulusci.core.tests.test_flowrunner._TaskReturnsBoolStr",
+            },
         }
         self.project_config.config["flows"] = {
             "nested_flow": {
@@ -542,6 +553,65 @@ def test_run__skip_conditional_step(self):
         flow.run(self.org_config)
         assert len(flow.results) == 0
 
+    def test_run__when_substitutes_prior_return_value__step_runs(self):
+        """A when clause with ^^path.key runs the step when the substituted value is truthy."""
+        flow_config = FlowConfig(
+            {
+                "steps": {
+                    1: {"task": "return_bool", "options": {"flag": "True"}},
+                    2: {"task": "pass_name", "when": "^^return_bool.flag"},
+                },
+            }
+        )
+        flow = FlowCoordinator(self.project_config, flow_config)
+        flow.run(self.org_config)
+        assert len(flow.results) == 2
+
+    def test_run__when_substitutes_prior_return_value__step_skipped(self):
+        """A when clause with ^^path.key skips the step when the substituted value is falsy."""
+        flow_config = FlowConfig(
+            {
+                "steps": {
+                    1: {"task": "return_bool", "options": {"flag": "False"}},
+                    2: {"task": "pass_name", "when": "^^return_bool.flag"},
+                },
+            }
+        )
+        flow = FlowCoordinator(self.project_config, flow_config)
+        flow.run(self.org_config)
+        assert len(flow.results) == 1
+
+    def test_run__when_substitutes_multiple_prior_return_values(self):
+        """Multiple ^^path.key references in a single when clause are each substituted."""
+        flow_config = FlowConfig(
+            {
+                "steps": {
+                    1: {"task": "return_bool", "options": {"flag": "True"}},
+                    2: {
+                        "task": "pass_name",
+                        "when": "^^return_bool.flag and ^^return_bool.flag",
+                    },
+                },
+            }
+        )
+        flow = FlowCoordinator(self.project_config, flow_config)
+        flow.run(self.org_config)
+        assert len(flow.results) == 2
+
+    def test_run__when_substitutes_prior_return_value__path_not_found(self):
+        """A NameError is raised when the ^^path in a when clause has no matching prior result."""
+        flow_config = FlowConfig(
+            {
+                "steps": {
+                    1: {"task": "return_bool"},
+                    2: {"task": "pass_name", "when": "^^no_such_task.flag"},
+                },
+            }
+        )
+        flow = FlowCoordinator(self.project_config, flow_config)
+        with pytest.raises(NameError):
+            flow.run(self.org_config)
+
     def test_run__task_raises_exception_fail(self):
         """A flow aborts when a task raises an exception"""