now workflow calls can be nested (fix #201)

this was made possible with this change by GitHub

https://github.blog/changelog/2022-08-22-github-actions-improvements-to-reusable-workflows-2/

docs/checks.md

@@ -1965,9 +1965,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - run: echo "${{ inputs.scheme }}://${{ inputs.host }}:${{ inputs.port }}${{ inputs.path }}"
-  nested:
-    # ERROR: Nested workflow call is not allowed
-    uses: onwer/repo/w.yml@main
 ```
 
 Output:
@@ -1989,21 +1986,13 @@ test.yaml:26:18: input "path" of workflow_call event has the default value "", b
    |
 26 |         default: ''
    |                  ^~
-test.yaml:35:11: reusable workflow cannot be nested. but this workflow hooks "workflow_call" event at line:2,col:3 [workflow-call]
-   |
-35 |     uses: onwer/repo/w.yml@main
-   |           ^~~~~~~~~~~~~~~~~~~~~
 ```
 
-[Playground](https://rhysd.github.io/actionlint#eJx9kc1ugzAQhO99ilVUKSdA/Tn51AfooT/quTKwFBLjdey1KIp499pAIkRLb/CtPTPeIS1uADqyx0pR91lIpSIAaLTx7KZvAFfU2OLlD6BEV9jGcENawPs4BKrg4+15caSSXrGAmtm4K+beoADHttFfM6zJsfh9D79laxSmBbX/3TZkeSPYSxhtxtqLu/uHx/1KWvs2RzvDk0fbb2i/xtlafNKg/IAFX+JJrrfihdFaweLJNxZLAWw9/pF6HXjexYHysaySJjPrtUuiic+9Zp8oyeimTI7RXItN4smw66Im2N2ez3Pv6VQ4DIPIsgWOVUW4QHH/AS1JfNcw7IKFDqbhMaOZd+jCcnSHNrNoKOvSvlVPrWz0D3BGvIY=)
-[Playground]()
+[Playground](https://rhysd.github.io/actionlint#eJx9kctuwyAQRff9ilFUKSsn6mPFN3TRh7quMB4XUswQGJRGkf+9JjiR5dbdwZnhzmUuOXEDcKDw1Vo6fChpbQYAxvnEsZwBotLY4eUG0GBUwXg25AS8nYtALby/Pk1aWpksC9DMPl4xHz0KiByM+xyhpsji9zv8lp23uFHU/ffaU+AFY89DadHWWtzdPzyuZ9IudTWGEe4ThuOC9kuuzcWLBtU7VHyxJ1kv2RtKc4WA+2QCNgI4JPzD9dzwuIsd1eewGirDQnKxykNSnRynykrGWDxFRn8Ntsqdw66VJljdnk5j7psSOPS92G4nOEeV4QTl/Q9oSvK/+n71A7U5rsA=)
 
 Unlike inputs of action, inputs of a workflow must specify their types. actionlint validates input types and checks the default
 values are correctly typed. For more details, see [the official document][create-reusable-workflow-doc].
 
-In addition, nested workflow call is not allowed. actionlint checks reusable workflow is not called when the workflow hooks
-`workflow_call` event.
-
 ### Check reusable workflow call syntax
 
 Example input:

rule_expression.go

@@ -922,8 +922,6 @@ func (rule *RuleExpression) checkWorkflowCallOutputs(outputs map[*String]*Workfl
 		var o *ObjectType
 		if j.WorkflowCall != nil {
 			// Outputs are not defined in jobs.<job_id> section when it is reusable workflow call.
-			// At the point of writing this comment, reusable workflow cannot be nested. So reaching
-			// here would cause other error in some other checks.
 			o = NewEmptyObjectType()
 		} else {
 			p := make(map[string]ExprType, len(j.Outputs))

rule_workflow_call.go

@@ -40,10 +40,6 @@ func (rule *RuleWorkflowCall) VisitJobPre(n *Job) error {
 		return nil
 	}
 
-	if rule.workflowCallEventPos != nil {
-		rule.errorf(u.Pos, "reusable workflow cannot be nested. but this workflow hooks \"workflow_call\" event at %s", rule.workflowCallEventPos)
-	}
-
 	if !strings.Contains(u.Value, "${{") && !(checkWorkflowCallUsesLocalFormat(u.Value) || checkWorkflowCallUsesRepoFormat(u.Value)) {
 		rule.errorf(u.Pos, "reusable workflow call %q at \"uses\" is not following the format \"owner/repo/path/to/workflow.yml@ref\" nor \"./path/to/workflow.yml\". see https://docs.github.com/en/actions/learn-github-actions/reusing-workflows for more details", u.Value)
 	}

rule_workflow_call_test.go

@@ -1,7 +1,6 @@
 package actionlint
 
 import (
-	"strings"
 	"testing"
 )
 
@@ -56,14 +55,11 @@ func TestRuleWorkflowCallCheckWorkflowCallUsesFormat(t *testing.T) {
 	}
 }
 
-func TestRuleWorkflowCallCheckCannotCallNestedly(t *testing.T) {
+func TestRuleWorkflowCallNestedWorkflowCalls(t *testing.T) {
 	w := &Workflow{
 		On: []Event{
 			&WorkflowCallEvent{
-				Pos: &Pos{
-					Line: 12,
-					Col:  34,
-				},
+				Pos: &Pos{},
 			},
 		},
 	}
@@ -86,17 +82,9 @@ func TestRuleWorkflowCallCheckCannotCallNestedly(t *testing.T) {
 	if err := r.VisitJobPre(j); err != nil {
 		t.Fatal(err)
 	}
+	errs := r.Errs()
 
-	err := r.Errs()[0]
-	msg := err.Error()
-
-	want := "reusable workflow cannot be nested"
-	if !strings.Contains(msg, want) {
-		t.Errorf("error message %q does not contain expected message %q", msg, want)
-	}
-
-	want = "line:12,col:34"
-	if !strings.Contains(msg, want) {
-		t.Errorf("error message %q does not contain proper position %q", msg, want)
+	if len(errs) > 0 {
+		t.Fatal("unexpected errors:", errs)
 	}
 }

testdata/examples/workflow_call_definitions.out

@@ -2,4 +2,3 @@ test.yaml:9:7: "description" is missing at "host" input of workflow_call event [
 test.yaml:16:18: input of workflow_call event "port" is typed as number but its default value ":1234" cannot be parsed as a float number: strconv.ParseFloat: parsing ":1234": invalid syntax [events]
 test.yaml:21:15: invalid value "object" for input type of workflow_call event. it must be one of "boolean", "number", or "string" [syntax-check]
 test.yaml:26:18: input "path" of workflow_call event has the default value "", but it is also required. if an input is marked as required, its default value will never be used [events]
-test.yaml:35:11: reusable workflow cannot be nested. but this workflow hooks "workflow_call" event at line:2,col:3 [workflow-call]

testdata/examples/workflow_call_definitions.yaml

@@ -30,6 +30,3 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - run: echo "${{ inputs.scheme }}://${{ inputs.host }}:${{ inputs.port }}${{ inputs.path }}"
-  nested:
-    # ERROR: Nested workflow call is not allowed
-    uses: onwer/repo/w.yml@main