Enforce that output files are created in primary ninja execution

Missing output files in ninja execution will be treated as errors.
Products can bypass this using the newly introduced
BUILD_BROKEN_MISSING_OUTPUTS flag.

Test: m nothing # verified missingoutfile appears in out/soong.log
Test: checkbuild passes on presubmits

Change-Id: I4eebcd08aa57fc6ccf1688c32e0d1fe06d66ab9a

ui/build/config.go

@@ -98,9 +98,10 @@ type configImpl struct {
 	// Autodetected
 	totalRAM uint64
 
-	brokenDupRules     bool
-	brokenUsesNetwork  bool
-	brokenNinjaEnvVars []string
+	brokenDupRules       bool
+	brokenUsesNetwork    bool
+	brokenNinjaEnvVars   []string
+	brokenMissingOutputs bool
 
 	pathReplaced bool
 
@@ -1591,6 +1592,14 @@ func (c *configImpl) BuildBrokenNinjaUsesEnvVars() []string {
 	return c.brokenNinjaEnvVars
 }
 
+func (c *configImpl) SetBuildBrokenMissingOutputs(val bool) {
+	c.brokenMissingOutputs = val
+}
+
+func (c *configImpl) BuildBrokenMissingOutputs() bool {
+	return c.brokenMissingOutputs
+}
+
 func (c *configImpl) SetTargetDeviceDir(dir string) {
 	c.targetDeviceDir = dir
 }

ui/build/dumpvars.go

@@ -235,6 +235,11 @@ func runMakeProductConfig(ctx Context, config Config) {
 		"BUILD_BROKEN_SRC_DIR_IS_WRITABLE",
 		"BUILD_BROKEN_SRC_DIR_RW_ALLOWLIST",
 
+		// Whether missing outputs should be treated as warnings
+		// instead of errors.
+		// `true` will relegate missing outputs to warnings.
+		"BUILD_BROKEN_MISSING_OUTPUTS",
+
 		// Not used, but useful to be in the soong.log
 		"TARGET_BUILD_TYPE",
 		"HOST_ARCH",
@@ -301,4 +306,5 @@ func runMakeProductConfig(ctx Context, config Config) {
 	config.SetBuildBrokenUsesNetwork(makeVars["BUILD_BROKEN_USES_NETWORK"] == "true")
 	config.SetBuildBrokenNinjaUsesEnvVars(strings.Fields(makeVars["BUILD_BROKEN_NINJA_USES_ENV_VARS"]))
 	config.SetSourceRootDirs(strings.Fields(makeVars["PRODUCT_SOURCE_ROOT_DIRS"]))
+	config.SetBuildBrokenMissingOutputs(makeVars["BUILD_BROKEN_MISSING_OUTPUTS"] == "true")
 }

ui/build/ninja.go

@@ -77,6 +77,14 @@ func runNinjaForBuild(ctx Context, config Config) {
 		"-w", "dupbuild=err",
 		"-w", "missingdepfile=err")
 
+	if !config.BuildBrokenMissingOutputs() {
+		// Missing outputs will be treated as errors.
+		// BUILD_BROKEN_MISSING_OUTPUTS can be used to bypass this check.
+		args = append(args,
+			"-w", "missingoutfile=err",
+		)
+	}
+
 	cmd := Command(ctx, config, "ninja", executable, args...)
 
 	// Set up the nsjail sandbox Ninja runs in.