stackeval: More robust absolute source addrs

Instead of relying on the module call's source being unique, we now use
the entire path as the key for looking up the parent's absolute source
address.

internal/stacks/stackruntime/internal/stackeval/component_config.go

@@ -452,16 +452,16 @@ func (c *ComponentConfig) tracingName() string {
 // sourceBundleModuleWalker is an implementation of [configs.ModuleWalker]
 // that loads all modules from a single source bundle.
 type sourceBundleModuleWalker struct {
-	rootModuleSource    sourceaddrs.FinalSource
-	absoluteSourceAddrs map[addrs.ModuleSource]sourceaddrs.FinalSource
+	absoluteSourceAddrs map[string]sourceaddrs.FinalSource
 	sources             *sourcebundle.Bundle
 	parser              *configs.SourceBundleParser
 }
 
 func newSourceBundleModuleWalker(rootModuleSource sourceaddrs.FinalSource, sources *sourcebundle.Bundle, parser *configs.SourceBundleParser) *sourceBundleModuleWalker {
+	absoluteSourceAddrs := make(map[string]sourceaddrs.FinalSource, 1)
+	absoluteSourceAddrs[addrs.RootModule.String()] = rootModuleSource
 	return &sourceBundleModuleWalker{
-		rootModuleSource:    rootModuleSource,
-		absoluteSourceAddrs: make(map[addrs.ModuleSource]sourceaddrs.FinalSource),
+		absoluteSourceAddrs: absoluteSourceAddrs,
 		sources:             sources,
 		parser:              parser,
 	}
@@ -507,7 +507,7 @@ func (w *sourceBundleModuleWalker) LoadModule(req *configs.ModuleRequest) (*conf
 	// We store the absolute source address for this module so that any in-repo
 	// child modules can use it to construct their absolute source addresses
 	// too.
-	w.absoluteSourceAddrs[req.SourceAddr] = absoluteSourceAddr
+	w.absoluteSourceAddrs[req.Path.String()] = absoluteSourceAddr
 
 	_, err = w.sources.LocalPathForSource(absoluteSourceAddr)
 	if err != nil {
@@ -603,13 +603,15 @@ func (w *sourceBundleModuleWalker) bundleSourceAddrForTerraformSourceAddr(tfSour
 func (w *sourceBundleModuleWalker) absoluteSourceAddr(sourceAddr sourceaddrs.FinalSource, parent *configs.Config) (sourceaddrs.FinalSource, error) {
 	switch source := sourceAddr.(type) {
 	case sourceaddrs.LocalSource:
-		parentSourceAddr := w.rootModuleSource
+		parentPath := addrs.RootModule
 		if parent != nil {
-			if p, ok := w.absoluteSourceAddrs[parent.SourceAddr]; ok {
-				parentSourceAddr = p
-			}
+			parentPath = parent.Path
+		}
+		absoluteParentSourceAddr, ok := w.absoluteSourceAddrs[parentPath.String()]
+		if !ok {
+			return nil, fmt.Errorf("unexpected missing source address for module parent %q", parentPath)
 		}
-		return sourceaddrs.ResolveRelativeFinalSource(parentSourceAddr, source)
+		return sourceaddrs.ResolveRelativeFinalSource(absoluteParentSourceAddr, source)
 	default:
 		return sourceAddr, nil
 	}