SERVER-65901 scons.py silently ignores invalid variable-files parameter

1 files changed, 32 insertions, 0 deletions

diff --git a/SConstruct b/SConstruct
index 7267eed814d..580cb459b03 100755
--- a/SConstruct
+++ b/SConstruct
@@ -19,6 +19,7 @@ from glob import glob
 from pkg_resources import parse_version
 
 import SCons
+import SCons.Script
 
 # This must be first, even before EnsureSConsVersion, if
 # we are to avoid bulk loading all tools in the DefaultEnvironment.
@@ -55,8 +56,18 @@ print('scons: running with args {}'.format(scons_invocation))
 
 atexit.register(mongo.print_build_failures)
 
+# An extra instance of the SCons parser is used to manually validate options
+# flags. We use it detect some common misspellings/unknown options and
+# communicate with the user more effectively than just allowing Configure to
+# fail.
+# This is to work around issue #4187
+# (https://github.com/SCons/scons/issues/4187). Upon a future upgrade to SCons
+# that incorporates #4187, we should replace this solution with that.
+_parser = SCons.Script.SConsOptions.Parser("")
+
 
 def add_option(name, **kwargs):
+    _parser.add_option('--' + name, **{"default": None, **kwargs})
 
     if 'dest' not in kwargs:
         kwargs['dest'] = name
@@ -883,6 +894,27 @@ for vf in variables_files:
         fatal_error(None, f"Specified variables file '{vf}' does not exist")
     print(f"Using variable customization file {vf}")
 
+# Critically, this approach is technically incorrect. While all MongoDB
+# SConscript files use our add_option wrapper, builtin tools can
+# access SCons's GetOption/AddOption methods directly, causing their options
+# to not be validated by this block.
+(_, leftover) = _parser.parse_args(sys.argv)
+# leftover contains unrecognized options, including environment variables,and
+# the argv[0]. If we only look at flags starting with --, and we skip the first
+# leftover value (argv[0]), anything that remains is an invalid option
+invalid_options = list(filter(lambda x: x.startswith("--"), leftover[1:]))
+if len(invalid_options) > 0:
+    # users frequently misspell "variables-files" (note two `s`s) as
+    # "variable-files" or "variables-file". Detect and help them out.
+    for opt in invalid_options:
+        bad_var_file_opts = ["--variable-file", "--variables-file", "--variable-files"]
+        if opt in bad_var_file_opts or any(
+            [opt.startswith(f"{bad_opt}=") for bad_opt in bad_var_file_opts]):
+            print(
+                f"WARNING: You supplied the invalid parameter '{opt}' to SCons. Did you mean --variables-files (both words plural)?"
+            )
+    fatal_error(None, f"ERROR: unknown options supplied to scons: {invalid_options}")
+
 env_vars = Variables(
     files=variables_files,
     args=ARGUMENTS,