Fix an issue in `gn analyze` when building all.

tools/gn/analyzer.cc

Index: tools/gn/analyzer.cc
diff --git a/tools/gn/analyzer.cc b/tools/gn/analyzer.cc
index f89c93dfef20e134ce5db6b6fd34e58806ef697a..d73a23b63890edc612c833a1f0a5dfc28c73874b 100644
--- a/tools/gn/analyzer.cc
+++ b/tools/gn/analyzer.cc
@@ -43,6 +43,7 @@ struct Inputs {
 struct Outputs {
   std::string status;
   std::string error;
+  bool compile_includes_all;
   LabelSet compile_labels;
   LabelSet test_labels;
   LabelSet invalid_labels;
@@ -203,8 +204,14 @@ std::string OutputsToJSON(const Outputs& outputs,
                 outputs.invalid_labels);
   } else {
     WriteString(*value, "status", outputs.status);
-    WriteLabels(default_toolchain, *value, "compile_targets",
-                outputs.compile_labels);
+    if (outputs.compile_includes_all) {
+      auto compile_targets = base::WrapUnique(new base::ListValue());

[Nico, 2016/09/20 19:20:44]

For better or worse, I think we have decided to prefer `=
base::MakeUnique<base::ListValue>()` instead of `WrapUnique(new )`

[Dirk Pranke, 2016/09/20 19:24:17]

I think we mostly use WrapUnique() elsewhere, still, so I'd probably leave this
as-is for now and defer cleanup to a subsequent change, unless brettw@ also
wants me to change this now.

+      compile_targets->AppendString("all");
+      value->Set("compile_targets", std::move(compile_targets));
+    } else {
+      WriteLabels(default_toolchain, *value, "compile_targets",
+                  outputs.compile_labels);
+    }
     WriteLabels(default_toolchain, *value, "test_targets", outputs.test_labels);
   }
 
@@ -232,8 +239,8 @@ Analyzer::Analyzer(const Builder& builder)
 Analyzer::~Analyzer() {}
 
 std::string Analyzer::Analyze(const std::string& input, Err* err) const {
-  Inputs inputs;
-  Outputs outputs;
+  Inputs inputs = Inputs();
+  Outputs outputs = Outputs();

[Dirk Pranke, 2016/09/20 18:54:23]

Is this the best way to make sure everything is zero/value-initialized?

[Nico, 2016/09/20 19:16:59]

The best way is to give your thing a ctor, eg by doing

  struct Outputs {
    ...
    bool includes_all = false;
    ...
  };

Then you don't need to be careful everytime you make a variable of this type.

[Dirk Pranke, 2016/09/20 19:24:17]

Ah, I was wondering if you could do something like that, but couldn't find any
examples offhand and failed to think to just try it. Thanks!

 
   Err local_err = JSONToInputs(default_toolchain_, input, &inputs);
   if (local_err.has_error()) {
@@ -259,7 +266,14 @@ std::string Analyzer::Analyze(const std::string& input, Err* err) const {
   // or toolchain defined in that file.
   if (AnyBuildFilesWereModified(inputs.source_files)) {
     outputs.status = "Found dependency (all)";
-    outputs.compile_labels = inputs.compile_labels;
+    if (inputs.compile_included_all) {
+      outputs.compile_includes_all = true;
+    } else {
+      for (const auto label: inputs.compile_labels)
+        outputs.compile_labels.insert(label);
+      for (const auto label: inputs.test_labels)
+        outputs.compile_labels.insert(label);

[Dirk Pranke, 2016/09/20 18:54:23]

This is the thing that is equivalent to a set_union, but I couldn't figure out
how to the assignment operator happy; it seemed to want weird things to be
const. 

Let me know if you want me to keep playing with this, but I'd rather land a fix
first to avoid further incorrect builds.

[Nico, 2016/09/20 19:20:44]

I haven't looked at the docs of std::set, but I'd've expected something like
this to work:

  outputs.compile_labels.isert(inputs.compile_labels.begin(),
inputs.compile_labels.end());
  outputs.compile_labels.insert(inputs.test_labels.begin(),
inputs.test_labels.end());

[Dirk Pranke, 2016/09/20 19:24:17]

Yeah, that might also work, though I'm not sure that either that or set_union()
is actually clearer than what I've written.

[brettw, 2016/09/20 19:28:53]

Just do what Nico suggested. Since you already have a set, a union is trivial. I
realize now that the problem with your old code was using a set as the output
iterator. set_union is trying to write things out in order, while the
destination container is also thinking it has control over the order.

[Dirk Pranke, 2016/09/20 19:36:20]

ok, done.

+    }
     outputs.test_labels = inputs.test_labels;
     return OutputsToJSON(outputs, default_toolchain_, err);
   }