Add compiledb generation to test project and customs loading SConstruct

SConstruct

@@ -85,6 +85,11 @@ if env.GetOption("num_jobs") == altered_num_jobs:
 
 # Custom options and profile flags.
 customs = ["custom.py"]
+try:
+    customs += Import("customs")
+except:
+    pass
+
 profile = ARGUMENTS.get("profile", "")
 if profile:
     if os.path.isfile(profile):
@@ -265,9 +270,11 @@ if env["precision"] == "double":
     env.Append(CPPDEFINES=["REAL_T_IS_DOUBLE"])
 
 # compile_commands.json
+compilation_db = None
 if env.get("compiledb", False):
     env.Tool("compilation_db")
-    env.Alias("compiledb", env.CompilationDatabase(normalize_path(env["compiledb_file"])))
+    compilation_db = env.CompilationDatabase(normalize_path(env["compiledb_file"]))
+    env.Alias("compiledb", compilation_db)
 
 # Generate bindings
 env.Append(BUILDERS={"GenerateBindings": Builder(action=scons_generate_bindings, emitter=scons_emit_files)})
@@ -316,7 +323,10 @@ library_name = "libgodot-cpp{}{}".format(suffix, env["LIBSUFFIX"])
 
 if env["build_library"]:
     library = env.StaticLibrary(target=env.File("bin/%s" % library_name), source=sources)
-    Default(library)
+    default_args = [library]
+    if not compilation_db is None:
+        default_args += [compilation_db]
+    Default(*default_args)
 
 env.Append(LIBPATH=[env.Dir("bin")])
 env.Append(LIBS=library_name)

test/.gitignore

@@ -23,3 +23,6 @@ mono_crash.*.json
 # System/tool-specific ignores
 .directory
 *~
+
+# Build configuarion.
+/custom.py

test/SConstruct

@@ -1,8 +1,49 @@
 #!/usr/bin/env python
 import os
 import sys
+from SCons.Errors import UserError
 
-env = SConscript("../SConstruct")
+
+def normalize_path(val, env):
+    return val if os.path.isabs(val) else os.path.join(env.Dir("#").abspath, val)
+
+
+def validate_parent_dir(key, val, env):
+    if not os.path.isdir(normalize_path(os.path.dirname(val), env)):
+        raise UserError("'%s' is not a directory: %s" % (key, os.path.dirname(val)))
+
+
+localEnv = Environment()
+customs = ["custom.py"]
+opts = Variables(customs, ARGUMENTS)
+
+opts.Add(
+    BoolVariable(
+        key="compiledb",
+        help="Generate compilation DB (`compile_commands.json`) for external tools",
+        default=localEnv.get("compiledb", False),
+    )
+)
+opts.Add(
+    PathVariable(
+        key="compiledb_file",
+        help="Path to a custom `compile_commands.json` file",
+        default=localEnv.get("compiledb_file", "compile_commands.json"),
+        validator=validate_parent_dir,
+    )
+)
+
+opts.Update(localEnv)
+
+env = localEnv.Clone()
+env["compiledb"] = False
+env = SConscript("../SConstruct", {"env": env, "customs": customs})
+
+compilation_db = None
+if localEnv.get("compiledb", False):
+    env.Tool("compilation_db")
+    compilation_db = env.CompilationDatabase(normalize_path(env["compiledb_file"], env))
+    env.Alias("compiledb", compilation_db)
 
 # For the reference:
 # - CCFLAGS are compilation flags shared between C and C++
@@ -29,4 +70,8 @@ else:
         source=sources,
     )
 
-Default(library)
+default_args = [library]
+if not compilation_db is None:
+    default_args += [compilation_db]
+
+Default(*default_args)