Ninja: 'ninja -t compdb' should dump every rule

I'm also confused by this tool. I don't have problems passing rule names like cc cxx if they exist, but my problem with it was that I figured with no arguments, it should dump every rule it knows about, and only fallback to filtering when you give it arguments to do so.

I'm not sure if it's the project I work on or CMake, but when run using CMake in this project, the rule names are incredibly baroque and plentiful, so typing them all out is a non-starter for me. Instead, I use this patch to the package on my Ubuntu computer,

--- ninja-build-1.7.2.orig/src/ninja.cc
+++ ninja-build-1.7.2/src/ninja.cc
@@ -638,20 +638,36 @@ int NinjaMain::ToolCompilationDatabase(c
        e != state_.edges_.end(); ++e) {
     if ((*e)->inputs_.empty())
       continue;
-    for (int i = 0; i != argc; ++i) {
-      if ((*e)->rule_->name() == argv[i]) {
-        if (!first)
-          putchar(',');

-        printf("\n  {\n    \"directory\": \"");
-        EncodeJSONString(&cwd[0]);
-        printf("\",\n    \"command\": \"");
-        EncodeJSONString((*e)->EvaluateCommand().c_str());
-        printf("\",\n    \"file\": \"");
-        EncodeJSONString((*e)->inputs_[0]->path().c_str());
-        printf("\"\n  }");
+    if (argc == 0) {
+      if (!first)
+        putchar(',');

-        first = false;
+      printf("\n  {\n    \"directory\": \"");
+      EncodeJSONString(&cwd[0]);
+      printf("\",\n    \"command\": \"");
+      EncodeJSONString((*e)->EvaluateCommand().c_str());
+      printf("\",\n    \"file\": \"");
+      EncodeJSONString((*e)->inputs_[0]->path().c_str());
+      printf("\"\n  }");
+
+      first = false;
+    } else {
+      for (int i = 0; i != argc; ++i) {
+        if ((*e)->rule_->name() == argv[i]) {
+          if (!first)
+            putchar(',');
+
+          printf("\n  {\n    \"directory\": \"");
+          EncodeJSONString(&cwd[0]);
+          printf("\",\n    \"command\": \"");
+          EncodeJSONString((*e)->EvaluateCommand().c_str());
+          printf("\",\n    \"file\": \"");
+          EncodeJSONString((*e)->inputs_[0]->path().c_str());
+          printf("\"\n  }");
+
+          first = false;
+        }
       }
     }
   }

I never bothered cleaning it and posting to the list, because CMake provides it's own way to generate compile commands, but the above might help you in your situation.

I figured with no arguments, it should dump every rule it knows about, and only fallback to filtering when you give it arguments to do so.

That sounds reasonable to me.

As mentioned on https://github.com/ninja-build/ninja/issues/1024#issuecomment-178885017 , I think this would be a good change.

yes please.....