internal/rosa: use string pair for files

This is a much cleaner representation than the separator syntax.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/state.go

@@ -899,7 +899,7 @@ func (ctx *evalContext) pf(
 	var (
 		attr    PackageAttr
 		patches []string
-		files   []string
+		files   []KV
 		excl    bool
 		early   bool
 
@@ -965,16 +965,17 @@ func (ctx *evalContext) pf(
 
 	for _, pair := range files {
 		var pathname *check.Absolute
-		dst, src, ok := strings.Cut(pair, ":")
-		if !ok {
-			src, dst = dst, filepath.Base(dst)
+		if pathname, err = check.NewAbs(pair[0]); err != nil {
+			pathname = AbsUsrSrc.Append(pair[0])
+			err = nil
 		}
-		if pathname, err = check.NewAbs(dst); err != nil {
-			pathname = AbsUsrSrc.Append(dst)
+
+		if pair[1] == "" {
+			pair[1] = pair[0]
 		}
 
 		var p []byte
-		p, err = fs.ReadFile(ctx.b, src)
+		p, err = fs.ReadFile(ctx.b, pair[1])
 		if err != nil {
 			return
 		}
@@ -982,8 +983,8 @@ func (ctx *evalContext) pf(
 		attr.Paths = append(attr.Paths, pkg.Path(
 			pathname,
 			false,
-			pkg.NewFile(filepath.Base(dst), p),
-		))
+			pkg.NewFile(filepath.Base(pair[0]), p)),
+		)
 	}
 
 	if excl {