go/ast: fix ast.MergePackageFiles to collect infos about imports

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/4710047

diff --git a/src/pkg/go/ast/filter.go b/src/pkg/go/ast/filter.go
index 26733430d64d65291e9333f9910d76f5938c5fdc..4c96e71c0371cd0376b92f1776514cf43e278e41 100644 (file)
--- a/src/pkg/go/ast/filter.go
+++ b/src/pkg/go/ast/filter.go
@@ -344,6 +344,8 @@ const (
        // If set, comments that are not associated with a specific
        // AST node (as Doc or Comment) are excluded.
        FilterUnassociatedComments
+       // If set, duplicate import declarations are excluded.
+       FilterImportDuplicates
 )
 
 // separator is an empty //-style comment that is interspersed between
@@ -459,6 +461,32 @@ func MergePackageFiles(pkg *Package, mode MergeMode) *File {
                }
        }
 
+       // Collect import specs from all package files.
+       var imports []*ImportSpec
+       if mode&FilterImportDuplicates != 0 {
+               seen := make(map[string]bool)
+               for _, f := range pkg.Files {
+                       for _, imp := range f.Imports {
+                               path := imp.Path.Value
+                               if !seen[path] {
+                                       //TODO: consider handling cases where:
+                                       // - 2 imports exist with the same import path but
+                                       //   have different local names (one should probably 
+                                       //   keep both of them)
+                                       // - 2 imports exist but only one has a comment
+                                       // - 2 imports exist and they both have (possibly
+                                       //   different) comments
+                                       seen[path] = true
+                                       imports = append(imports, imp)
+                               }
+                       }
+               }
+       } else {
+               for _, f := range pkg.Files {
+                       imports = append(imports, f.Imports...)
+               }
+       }
+
        // Collect comments from all package files.
        var comments []*CommentGroup
        if mode&FilterUnassociatedComments == 0 {
@@ -469,7 +497,6 @@ func MergePackageFiles(pkg *Package, mode MergeMode) *File {
                }
        }
 
-       // TODO(gri) need to compute pkgScope and unresolved identifiers!
-       // TODO(gri) need to compute imports!
-       return &File{doc, pos, NewIdent(pkg.Name), decls, nil, nil, nil, comments}
+       // TODO(gri) need to compute unresolved identifiers!
+       return &File{doc, pos, NewIdent(pkg.Name), decls, pkg.Scope, imports, nil, comments}
 }