buildozer fails to find targets that are macros with a return value assigned to a variable

[mattnworb]

I'm not sure if this is an actual bug or we are doing something weird, but I've found that if we have a BUILD file with a target which is a macro that returns a value (such as a struct, with the names of a few internally instantiated targets), then a command like buildozer 'print label srcs' //foo will print an error that the rule cannot be found, even if buildozer 'print label srcs' //foo:* shows that the rule exists.

I created a repo which reproduces the issue: https://github.com/mattnworb/buildozer-macro-return-issue

For instance, in //hello-world/BUILD.bazel, there is a target that creates a java_binary via a macro:

macro_java_binary(
    name = "hello-world",
    srcs = ["src/main/java/com/mattnworb/example/Main.java"],
    main_class = "com.mattnworb.example.Main",
)

❯ buildozer 'print label srcs' //hello-world
//hello-world [src/main/java/com/mattnworb/example/Main.java]

but if the macro is made to return something, and that value is assigned to a variable in the BUILD.bazel file, then buildozer can no longer find the rule/target:

foo = macro_java_binary(
    name = "hello-world",
    srcs = ["src/main/java/com/mattnworb/example/Main.java"],
    main_class = "com.mattnworb.example.Main",
)

❯ buildozer 'print label srcs' //hello-world
/Users/mattbrown/code/buildozer-issue-repro/hello-world/BUILD.bazel: error while executing commands [{[print label srcs]}] on target //hello-world: rule 'hello-world' not found

even though buildozer can execute the command against the target in question, when expanding wildcards:

❯ buildozer 'print label srcs' //hello-world:*
//hello-world [src/main/java/com/mattnworb/example/Main.java]

---

I think a part of the issue is that

buildtools/edit/edit.go

Lines 295 to 325 in be1c24c

	func IndexOfRuleByName(f *build.File, name string) (int, *build.Rule) {
	linenum := -1
	if strings.HasPrefix(name, "%") {
	// "%<LINENUM>" will match the rule which begins at LINENUM.
	// This is for convenience, "%" is not a valid character in bazel targets.
	if result, err := strconv.Atoi(name[1:]); err == nil {
	linenum = result
	}
	}
	for i, stmt := range f.Stmt {
	call, ok := stmt.(*build.CallExpr)
	if !ok {
	continue
	}
	r := f.Rule(call)
	start, _ := call.X.Span()
	if r.Name() == name || start.Line == linenum {
	return i, r
	}
	// Allow for precisely targeting the package declaration. This
	// helps adding new load() and license() rules
	if name == "__pkg__" {
	if rule, ok := ExprToRule(stmt, "package"); ok {
	return i, rule
	}
	}
	}
	return -1, nil
	}

only examines nodes in the BUILD file AST which are CallExpr, and assigning the return value of a macro (which I can't tell is an unorthodox thing to do?) changes that node to an AssignExpr.