Replace —print-build-dir with --dump-config

The --dump-config option prints a recursive JSON dump of the BuildScriptInvocation object’s properties, which gives access to essentially all of the knowledge build-script has about the build before it starts performing it. This makes the output more flexible and extensible without severely convoluting the implementation, but doesn’t really give us a stable representation of that data.

Author: beccadax

utils/build-script

@@ -12,6 +12,7 @@
 from __future__ import print_function
 
 import argparse
+import json
 import os
 import pipes
 import platform
@@ -56,6 +57,15 @@ def exit_rejecting_arguments(message, parser=None):
     sys.exit(2)  # 2 is the same as `argparse` error exit code.
 
 
+class JSONDumper(json.JSONEncoder):
+    def __init__(self, *args, **kwargs):
+        json.JSONEncoder.__init__(self, indent=2, separators=(',', ': '),
+                                  *args, **kwargs)
+    
+    def default(self, o):
+        return vars(o)
+
+
 class HostSpecificConfiguration(object):
 
     """Configuration information for an individual host."""
@@ -1093,8 +1103,9 @@ def main_preset():
         "--build-dir",
         help="specify the directory where build artifact should be stored")
     parser.add_argument(
-        "--print-build-dir",
-        help="Print the build directory and exit without building",
+        "--dump-config",
+        help="instead of building, write JSON to stdout containing "
+             "various values used to build in this configuration",
         action="store_true",
         default=False)
     args = parser.parse_args()
@@ -1146,8 +1157,8 @@ def main_preset():
     build_script_args = [sys.argv[0]]
     if args.dry_run:
         build_script_args += ["--dry-run"]
-    if args.print_build_dir:
-        build_script_args += ["--print-build-dir"]
+    if args.dump_config:
+        build_script_args += ["--dump-config"]
 
     build_script_args += preset_args
     if args.distcc:
@@ -1233,8 +1244,8 @@ def main_normal():
     if args.show_sdks:
         debug.print_xcodebuild_versions()
 
-    if args.print_build_dir:
-        print(invocation.workspace.build_root)
+    if args.dump_config:
+        print(JSONDumper().encode(invocation))
         return 0
 
     # Clean build directory if requested.

utils/build_swift/driver_arguments.py

@@ -287,6 +287,10 @@ def create_argument_parser():
     option(['-n', '--dry-run'], store_true,
            help='print the commands that would be executed, but do not '
                 'execute them')
+    option('--dump-config', toggle_true,
+           help='instead of building, write JSON to stdout containing '
+                'various values used to build in this configuration')
+
     option('--legacy-impl', store_true('legacy_impl'),
            help='use legacy implementation')
 
@@ -333,8 +337,6 @@ def create_argument_parser():
            metavar='PATH',
            help='name of the directory under $SWIFT_BUILD_ROOT where the '
                 'build products will be placed')
-    option('--print-build-dir', toggle_true,
-           help='print the build directory and exit without building')
     option('--install-prefix', store_path,
            default=targets.install_prefix(),
            help='The installation prefix. This is where built Swift products '

utils/build_swift/tests/expected_options.py

@@ -161,7 +161,7 @@
     'tsan_libdispatch_test': False,
     'long_test': False,
     'lto_type': None,
-    'print_build_dir': False,
+    'dump_config': False,
     'show_sdks': False,
     'skip_build': False,
     'stdlib_deployment_targets': None,
@@ -403,7 +403,7 @@ class IgnoreOption(_BaseOption):
     SetTrueOption('--benchmark'),
     SetTrueOption('--clean'),
     SetTrueOption('--dry-run'),
-    SetTrueOption('--print-build-dir'),
+    SetTrueOption('--dump-config'),
     SetTrueOption('--disable-guaranteed-normal-arguments'),
     SetTrueOption('--enable-stdlibcore-exclusivity-checking'),
     SetTrueOption('--force-optimized-typechecker'),