feat: add linter support for step-level depends_on existence (#4657)

pipeline/frontend/yaml/linter/linter.go

@@ -161,11 +161,37 @@ func (l *Linter) lintContainers(config *WorkflowConfig, area string) error {
 		if err := l.lintContainerDeprecations(config, container, area); err != nil {
 			linterErr = multierr.Append(linterErr, err)
 		}
+		if err := l.lintDependsOn(config, container, area); err != nil {
+			linterErr = multierr.Append(linterErr, err)
+		}
 	}
 
 	return linterErr
 }
 
+func (l *Linter) lintDependsOn(config *WorkflowConfig, c *types.Container, area string) error {
+	if area != "steps" {
+		return nil
+	}
+
+	var linterErr error
+check:
+	for _, dep := range c.DependsOn {
+		for _, step := range config.Workflow.Steps.ContainerList {
+			if dep == step.Name {
+				continue check
+			}
+		}
+		linterErr = multierr.Append(linterErr,
+			newLinterError(
+				"One or more of the specified dependencies do not exist",
+				config.File, fmt.Sprintf("%s.%s.depends_on", area, c.Name), false,
+			),
+		)
+	}
+	return linterErr
+}
+
 func (l *Linter) lintImage(config *WorkflowConfig, c *types.Container, area string) error {
 	if len(c.Image) == 0 {
 		return newLinterError("Invalid or missing image", config.File, fmt.Sprintf("%s.%s", area, c.Name), false)

pipeline/frontend/yaml/linter/linter_test.go

@@ -185,6 +185,10 @@ func TestLintErrors(t *testing.T) {
 			from: "steps: { build: { image: golang, secrets: [ 'mysql_username' ] } }",
 			want: "Usage of `secrets` is deprecated, use `environment` in combination with `from_secret`",
 		},
+		{
+			from: "steps: { build: { image: golang }, publish: { image: golang, depends_on: [ binary ] } }",
+			want: "One or more of the specified dependencies do not exist",
+		},
 	}
 
 	for _, test := range testdata {