add go as a required dependency to build plan

[#167707118]

Co-authored-by: Forest Eckhardt <[email protected]>

cmd/detect/main.go

@@ -15,6 +15,7 @@ import (
 
 const MissingGopkgErrorMsg = "no Gopkg.toml found at root level"
 const EmptyTargetEnvVariableMsg = "BP_GO_TARGETS set but with empty value"
+const GoDependency = "go"
 
 type BuildpackYAML struct {
 	Config Config `yaml:"go"`
@@ -87,6 +88,8 @@ func runDetect(context detect.Detect) (int, error) {
 			Requires: []buildplan.Required{{
 				Name: dep.Dependency,
 				Metadata: metadata,
+			}, {
+				Name: GoDependency,
 			}},
 		})
 	}
@@ -98,6 +101,8 @@ func runDetect(context detect.Detect) (int, error) {
 		Requires: []buildplan.Required{{
 			Name: dep.Dependency,
 			Metadata: buildplan.Metadata{"build": true},
+		}, {
+			Name: GoDependency,
 		}},
 	})
 }

cmd/detect/main_test.go

@@ -51,6 +51,8 @@ func testDetect(t *testing.T, when spec.G, it spec.S) {
 				Requires: []buildplan.Required{{
 					Name:     dep.Dependency,
 					Metadata: buildplan.Metadata{"build": true},
+				}, {
+					Name: GoDependency,
 				}},
 			}))
 		})
@@ -89,6 +91,8 @@ go:
 							"import-path": "some/app",
 							"targets":     []string{"./path/to/first", "./path/to/second"},
 						},
+					}, {
+						Name: GoDependency,
 					}},
 				}
 
@@ -112,6 +116,8 @@ go:
 								"build":       true,
 								"import-path": "some/app",
 								"targets":     []string{"./path/to/third", "./path/to/fourth"}},
+						},{
+							Name: GoDependency,
 						}},
 					}
 
@@ -151,6 +157,8 @@ go:
 					Requires: []buildplan.Required{{
 						Name:     dep.Dependency,
 						Metadata: buildplan.Metadata{"build": true},
+					}, {
+						Name: GoDependency,
 					}},
 				}))
 			})