Merge "Handle nil variant in applyTransitions" into main am: 515e7991fc

Original change: https://android-review.googlesource.com/c/platform/build/blueprint/+/3080846

Change-Id: Ia353694df8a7a48c0ffc5bde48162d83338fae7d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

context.go

@@ -1877,7 +1877,7 @@ func (c *Context) findReverseDependency(module *moduleInfo, config any, destName
 // modify the requested variation.  It finds a variant that existed before the TransitionMutator ran that is
 // a subset of the requested variant to use as the module context for IncomingTransition.
 func (c *Context) applyTransitions(config any, module *moduleInfo, group *moduleGroup, variant variationMap,
-	requestedVariations []Variation) {
+	requestedVariations []Variation) variationMap {
 	for _, transitionMutator := range c.transitionMutators {
 		// Apply the outgoing transition if it was not explicitly requested.
 		explicitlyRequested := slices.ContainsFunc(requestedVariations, func(variation Variation) bool {
@@ -1903,6 +1903,9 @@ func (c *Context) applyTransitions(config any, module *moduleInfo, group *module
 				}
 
 				finalVariation := transitionMutator.mutator.IncomingTransition(ctx, outgoingVariation)
+				if variant == nil {
+					variant = make(variationMap)
+				}
 				variant[transitionMutator.name] = finalVariation
 				appliedIncomingTransition = true
 				break
@@ -1914,6 +1917,8 @@ func (c *Context) applyTransitions(config any, module *moduleInfo, group *module
 			delete(variant, transitionMutator.name)
 		}
 	}
+
+	return variant
 }
 
 func (c *Context) findVariant(module *moduleInfo, config any,
@@ -1940,7 +1945,7 @@ func (c *Context) findVariant(module *moduleInfo, config any,
 		newVariant[v.Mutator] = v.Variation
 	}
 
-	c.applyTransitions(config, module, possibleDeps, newVariant, requestedVariations)
+	newVariant = c.applyTransitions(config, module, possibleDeps, newVariant, requestedVariations)
 
 	check := func(variant variationMap) bool {
 		if far {

transition_test.go

@@ -86,7 +86,18 @@ const testTransitionBp = `
 			}
 
 			transition_module {
-				name: "F"
+				name: "F",
+			}
+
+			transition_module {
+				name: "G",
+				outgoing: "h",
+				%s
+			}
+
+			transition_module {
+				name: "H",
+				split: ["h"],
 			}
 		`
 
@@ -128,7 +139,7 @@ func checkTransitionMutate(t *testing.T, m *transitionModule, variant string) {
 }
 
 func TestTransition(t *testing.T) {
-	ctx, errs := testTransition(fmt.Sprintf(testTransitionBp, ""))
+	ctx, errs := testTransition(fmt.Sprintf(testTransitionBp, "", ""))
 	assertNoErrors(t, errs)
 
 	// Module A uses Split to create a and b variants
@@ -154,6 +165,8 @@ func TestTransition(t *testing.T) {
 	D_d := getTransitionModule(ctx, "D", "d")
 	E_d := getTransitionModule(ctx, "E", "d")
 	F := getTransitionModule(ctx, "F", "")
+	G := getTransitionModule(ctx, "G", "")
+	H_h := getTransitionModule(ctx, "H", "h")
 
 	checkTransitionDeps(t, ctx, A_a, "B(a)", "C(a)")
 	checkTransitionDeps(t, ctx, A_b, "B(b)", "C(b)")
@@ -165,6 +178,8 @@ func TestTransition(t *testing.T) {
 	checkTransitionDeps(t, ctx, D_d, "E(d)")
 	checkTransitionDeps(t, ctx, E_d)
 	checkTransitionDeps(t, ctx, F)
+	checkTransitionDeps(t, ctx, G)
+	checkTransitionDeps(t, ctx, H_h)
 
 	checkTransitionMutate(t, A_a, "a")
 	checkTransitionMutate(t, A_b, "b")
@@ -176,11 +191,14 @@ func TestTransition(t *testing.T) {
 	checkTransitionMutate(t, D_d, "d")
 	checkTransitionMutate(t, E_d, "d")
 	checkTransitionMutate(t, F, "")
+	checkTransitionMutate(t, G, "")
+	checkTransitionMutate(t, H_h, "h")
 }
 
 func TestPostTransitionDeps(t *testing.T) {
 	ctx, errs := testTransition(fmt.Sprintf(testTransitionBp,
-		`post_transition_deps: ["C", "D:late", "E:d", "F"],`))
+		`post_transition_deps: ["C", "D:late", "E:d", "F"],`,
+		`post_transition_deps: ["H"],`))
 	assertNoErrors(t, errs)
 
 	// Module A uses Split to create a and b variants
@@ -206,6 +224,8 @@ func TestPostTransitionDeps(t *testing.T) {
 	D_d := getTransitionModule(ctx, "D", "d")
 	E_d := getTransitionModule(ctx, "E", "d")
 	F := getTransitionModule(ctx, "F", "")
+	G := getTransitionModule(ctx, "G", "")
+	H_h := getTransitionModule(ctx, "H", "h")
 
 	checkTransitionDeps(t, ctx, A_a, "B(a)", "C(a)")
 	checkTransitionDeps(t, ctx, A_b, "B(b)", "C(b)")
@@ -222,6 +242,8 @@ func TestPostTransitionDeps(t *testing.T) {
 	checkTransitionDeps(t, ctx, D_d, "E(d)")
 	checkTransitionDeps(t, ctx, E_d)
 	checkTransitionDeps(t, ctx, F)
+	checkTransitionDeps(t, ctx, G, "H(h)")
+	checkTransitionDeps(t, ctx, H_h)
 
 	checkTransitionMutate(t, A_a, "a")
 	checkTransitionMutate(t, A_b, "b")
@@ -233,12 +255,14 @@ func TestPostTransitionDeps(t *testing.T) {
 	checkTransitionMutate(t, D_d, "d")
 	checkTransitionMutate(t, E_d, "d")
 	checkTransitionMutate(t, F, "")
+	checkTransitionMutate(t, G, "")
+	checkTransitionMutate(t, H_h, "h")
 }
 
 func TestPostTransitionDepsMissingVariant(t *testing.T) {
 	// TODO: eventually this will create the missing variant on demand
 	_, errs := testTransition(fmt.Sprintf(testTransitionBp,
-		`post_transition_deps: ["E:missing"],`))
+		`post_transition_deps: ["E:missing"],`, ""))
 	expectedError := `Android.bp:8:4: dependency "E" of "B" missing variant:
   transition:missing
 available variants: