test: Speed up Swift feature usage verification script

* The set of files that enable features and the set of files that
  require features are expected to have a very small, if any,
  difference. Don't compute and check each set separately.
* Find RUN and REQUIRES lines in a file in one go.

Author: AnthonyLatsis

test/Misc/verify-swift-feature-testing.test-sh

@@ -27,25 +27,27 @@ EXCEPTIONAL_FILES = [
     pathlib.Path("test/IDE/complete_decl_attribute_feature_requirement.swift"),
 ]
 
-FEATURE_USAGE_RE = re.compile(
+ENABLE_FEATURE_RE = re.compile(
     r"-enable-(?:experimental|upcoming)-feature (?:-Xfrontend )?([A-Za-z0-9]*)"
 )
-# Be careful of not using REQUIRES or RUN with a colon after them or Lit will
-# pick them up.
 FEATURE_LIT_MARKER_RE = re.compile(r"swift_feature_([A-Za-z0-9]*)")
 
 
-def find_test_files_with_features_usage(swift_src_root):
+def find_test_files(swift_src_root):
+    # Look for every test file in the test directories with `REQUIRES` lines
+    # that mention `swift_feature_`.
     # Look for every test file in the test directories with `RUN` lines that
     # mention `-enable-experimental-feature` or `-enable-upcoming-feature`.
-    # Be careful of not using REQUIRES or RUN with a colon after them or Lit will
+    # Be careful to not use RUN or REQUIRES with a colon after them or Lit will
     # pick them up.
     output = subprocess.check_output(
         [
             "grep",
             "--extended-regexp",
             "--recursive",
             "-e",
+            "REQUIRES[:].*swift_feature_",
+            "-e",
             "RUN[:].*-enable-(experimental|upcoming)-feature",
             "--files-with-matches",
             str(swift_src_root / "test"),
@@ -56,154 +58,68 @@ def find_test_files_with_features_usage(swift_src_root):
     return output.splitlines()
 
 
-def find_test_files_with_marker_usage(swift_src_root):
-    # Look for every test file in the test directories with `REQUIRES` lines
-    # that mention `swift_feature_`.
-    # Be careful of not using REQUIRES with a colon after them or Lit will
+def find_run_and_requires_lines(test_file):
+    # Be careful to not use RUN or REQUIRES with a colon after them or Lit will
     # pick them up.
-    output = subprocess.check_output(
-        [
-            "grep",
-            "--extended-regexp",
-            "--recursive",
-            "-e",
-            "REQUIRES[:].*swift_feature_",
-            "--files-with-matches",
-            str(swift_src_root / "test"),
-            str(swift_src_root / "validation-test"),
-        ],
-        text=True,
-    )
-    return output.splitlines()
-
-
-def find_run_lines(test_file):
     output = subprocess.check_output(
         [
             "grep",
             "--extended-regexp",
             "--no-filename",
             "-e",
             "RUN[:]",
-            str(test_file),
-        ],
-        text=True,
-    )
-    return output.splitlines()
-
-
-def find_requires_lines(test_file):
-    output = subprocess.check_output(
-        [
-            "grep",
-            "--extended-regexp",
-            "--no-filename",
             "-e",
             "REQUIRES[:]",
-            str(test_file),
+            test_file,
         ],
         text=True,
     )
     return output.splitlines()
 
 
-def check_existing_requires(test_file, feature):
-    returncode = subprocess.call(
-        [
-            "grep",
-            "--extended-regexp",
-            "--quiet",
-            "-e",
-            "REQUIRES[:].*swift_feature_" + feature,
-            str(test_file),
-        ]
-    )
-    return returncode != 0
+def check_test_file(test_file, existing_swift_features):
+    enabled_features = set()
+    required_features = set()
 
+    for line in find_run_and_requires_lines(test_file):
+        enabled_features.update(feature for feature in ENABLE_FEATURE_RE.findall(line))
+        required_features.update(
+            feature for feature in FEATURE_LIT_MARKER_RE.findall(line)
+        )
 
-def check_existing_feature_usage(test_file, feature):
-    returncode = subprocess.call(
-        [
-            "grep",
-            "--extended-regexp",
-            "--quiet",
-            "-e",
-            (
-                "RUN[:].*-enable-(experimental|upcoming)-feature (-Xfrontend )?"
-                + re.escape(feature)
-            ),
-            str(test_file),
-        ]
-    )
-    return returncode != 0
+    had_error = False
 
+    # First check for unknown features.
 
-def check_existing_error_message_checks(test_file, feature):
-    returncode = subprocess.call(
-        [
-            "grep",
-            "--extended-regexp",
-            "--quiet",
-            "-e",
-            "requires '-enable-(experimental|upcoming)-feature " + feature + "'",
-            str(test_file),
-        ]
-    )
-    return returncode != 0
+    for feature in enabled_features.difference(existing_swift_features):
+        enabled_features.remove(feature)
+        print(f"error: {test_file}: Unknown feature in RUN line: {feature}")
+        had_error = True
 
+    for feature in required_features.difference(existing_swift_features):
+        required_features.remove(feature)
+        print(f"error: {test_file}: Unknown feature in REQUIRES line: {feature}")
+        had_error = True
 
-def check_test_file_feature_usage(test_file, existing_swift_features):
-    run_lines = find_run_lines(test_file)
-    features = set(
-        feature for line in run_lines for feature in FEATURE_USAGE_RE.findall(line)
-    )
-    num_failures = 0
-    for feature in features:
-        # First, check this is a valid feature
-        if feature not in existing_swift_features:
-            print("error: {}: Unknown feature: {}".format(str(test_file), feature))
-            num_failures += 1
-            continue
+    # If the sets are equal, we're fine.
+    if enabled_features == required_features:
+        return had_error
 
-        # No warning if the necessary `REQUIRES` is already there
-        if not check_existing_requires(test_file, feature):
-            continue
+    # Then check for imbalances between required and enabled features.
 
-        # Some tests check for the errors themselves, so we can skip them as well
-        if not check_existing_error_message_checks(test_file, feature):
-            continue
+    for feature in enabled_features.difference(required_features):
+        # Be careful to not use REQUIRES with a colon after it or Lit will pick
+        # it up.
+        print(f"error: {test_file}: Missing 'REQUIRES" + f": swift_feature_{feature}'")
+        had_error = True
 
-        # For everything else, print a warning and add to the invalid exit code
+    for feature in required_features.difference(enabled_features):
         print(
-            "error: {}: Missing '{}: swift_feature_{}'".format(
-                str(test_file), "REQUIRES", feature
-            )
+            f"error: {test_file}: Missing '-enable-(experimental|upcoming)-feature: {feature}'"
         )
-        num_failures += 1
-    return num_failures == 0
+        had_error = True
 
-
-def check_test_file_marker_usage(test_file):
-    require_lines = find_requires_lines(test_file)
-    features = set(
-        feature
-        for line in require_lines
-        for feature in FEATURE_LIT_MARKER_RE.findall(line)
-    )
-    num_failures = 0
-    for feature in features:
-        # No warning if -enable-experimental/upcoming-feature is there
-        if not check_existing_feature_usage(test_file, feature):
-            continue
-
-        # For everything else, print a warning and add to the invalid exit code
-        print(
-            "error: {}: Missing '-enable-experimental/upcoming-feature: {}'".format(
-                str(test_file), feature
-            )
-        )
-        num_failures += 1
-    return num_failures == 0
+    return had_error
 
 
 def main():
@@ -214,29 +130,17 @@ def main():
     swift_src_root = pathlib.Path(sys.argv[1])
     existing_swift_features = set(json.loads(sys.argv[2]))
 
-    num_failures = 0
-    test_files_with_features_usage = find_test_files_with_features_usage(swift_src_root)
-    for test_file in test_files_with_features_usage:
-        test_file = pathlib.Path(test_file)
-        # First lets check this is not one of the exceptional files
-        if test_file.relative_to(swift_src_root) in EXCEPTIONAL_FILES:
-            continue
-
-        if not check_test_file_feature_usage(test_file, existing_swift_features):
-            num_failures += 1
-
-    test_files_with_marker_usage = find_test_files_with_marker_usage(swift_src_root)
-    for test_file in test_files_with_marker_usage:
-        test_file = pathlib.Path(test_file)
+    had_error = False
 
-        # First lets check this is not one of the exceptional files
-        if test_file.relative_to(swift_src_root) in EXCEPTIONAL_FILES:
+    for test_file in find_test_files(swift_src_root):
+        # Skip if this is one of the exceptional files.
+        if pathlib.Path(test_file).relative_to(swift_src_root) in EXCEPTIONAL_FILES:
             continue
 
-        if not check_test_file_marker_usage(test_file):
-            num_failures += 1
+        if check_test_file(test_file, existing_swift_features):
+            had_error = True
 
-    if num_failures > 0:
+    if had_error:
         sys.exit(1)