tools/fix: avoid name-mangled imports

By including a call to sanitize, and avoiding the ast cursor Import
method, we can avoid the name mangling of imports.

Fixes #3408

Signed-off-by: Matthew Sackman <matthew@cue.works>
Change-Id: I9bfc7082b504ac7a7d3c0a61580aef5bc8c3cd18
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1200498
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>

cmd/cue/cmd/testdata/script/fix.txtar

@@ -3,7 +3,6 @@ exec cue fix ./...
 cmp p/one.cue p/one.cue.fixed
 cmp p/two.cue p/two.cue.fixed
 cmp p/three.cue p/three.cue.fixed
-# TODO: the added imports have unnecessary name-mangling. https://cuelang.org/issue/3408
 -- p/one.cue --
 package one
 
@@ -17,16 +16,16 @@ out: ["a"] + ((["a"]*7) + ["gh"])
 -- p/one.cue.fixed --
 package one
 
-import list6c6973 "list"
+import "list"
 
-out: list6c6973.Concat([["foo"], ["bar"]])
+out: list.Concat([["foo"], ["bar"]])
 -- p/two.cue.fixed --
 package two
 
-import list6c6973 "list"
+import "list"
 
-out: list6c6973.Repeat(["baz"], 3)
+out: list.Repeat(["baz"], 3)
 -- p/three.cue.fixed --
-import list6c6973 "list"
+import "list"
 
-out: list6c6973.Concat([["a"], (list6c6973.Concat([(list6c6973.Repeat(["a"], 7)), ["gh"]]))])
+out: list.Concat([["a"], (list.Concat([(list.Repeat(["a"], 7)), ["gh"]]))])

tools/fix/fix.go

@@ -72,27 +72,27 @@ func File(f *ast.File, o ...Option) *ast.File {
 				if !(xIsList || yIsList) {
 					break
 				}
-				pkg := c.Import("list")
-				if pkg == nil {
-					break
-				}
 				if n.Op == token.ADD {
 					// Rewrite list addition to use list.Concat
 					ast.SetRelPos(x, token.NoSpace)
-					c.Replace(&ast.CallExpr{
-						Fun:  ast.NewSel(pkg, "Concat"),
-						Args: []ast.Expr{ast.NewList(x, y)},
-					})
+					c.Replace(ast.NewCall(
+						ast.NewSel(&ast.Ident{
+							Name: "list",
+							Node: ast.NewImport(nil, "list"),
+						}, "Concat"), ast.NewList(x, y)),
+					)
 				} else {
 					// Rewrite list multiplication to use list.Repeat
 					if !xIsList {
 						x, y = y, x
 					}
 					ast.SetRelPos(x, token.NoSpace)
-					c.Replace(&ast.CallExpr{
-						Fun:  ast.NewSel(pkg, "Repeat"),
-						Args: []ast.Expr{x, y},
-					})
+					c.Replace(ast.NewCall(
+						ast.NewSel(&ast.Ident{
+							Name: "list",
+							Node: ast.NewImport(nil, "list"),
+						}, "Repeat"), x, y),
+					)
 				}
 			}
 		}
@@ -103,5 +103,15 @@ func File(f *ast.File, o ...Option) *ast.File {
 		f = simplify(f)
 	}
 
+	err := astutil.Sanitize(f)
+	// TODO: this File method is public, and its signature was fixed
+	// before we started calling Sanitize. Ideally, we want to return
+	// this error, but that would require deprecating this File method,
+	// and creating a new one, which might happen in due course if we
+	// also discover that we need to be a bit more flexible than just
+	// accepting a File.
+	if err != nil {
+		panic(err)
+	}
 	return f
 }

tools/fix/fix_test.go

@@ -74,13 +74,13 @@ c: a + [8]
 d: [9] + a
 e: [0] + [1]
 `,
-			out: `import list6c6973 "list"
+			out: `import "list"
 
 a: [7]
 b: a + a
-c: list6c6973.Concat([a, [8]])
-d: list6c6973.Concat([[9], a])
-e: list6c6973.Concat([[0], [1]])
+c: list.Concat([a, [8]])
+d: list.Concat([[9], a])
+e: list.Concat([[0], [1]])
 `,
 		},
 
@@ -93,14 +93,14 @@ d: [7] * c
 e: c * [8]
 f: [9] * 5
 `,
-			out: `import list6c6973 "list"
+			out: `import "list"
 
 a: [7]
 b: a * 3
 c: 4
-d: list6c6973.Repeat([7], c)
-e: list6c6973.Repeat([8], c)
-f: list6c6973.Repeat([9], 5)
+d: list.Repeat([7], c)
+e: list.Repeat([8], c)
+f: list.Repeat([9], 5)
 `,
 		},
 	}
@@ -115,9 +115,9 @@ f: list6c6973.Repeat([9], 5)
 			if tc.simplify {
 				opts = append(opts, Simplify())
 			}
-			n := File(f, opts...)
+			File(f, opts...)
 
-			b, err := format.Node(n)
+			b, err := format.Node(f)
 			if err != nil {
 				t.Fatal(err)
 			}