feat: initial support for header mappings

Author: dsanders11

common.py

@@ -31,3 +31,4 @@ class Configuration(BaseModel):
     dependencies: Dict[str, Union[str, "Configuration"]] = {}
     includeDirs: List[str] = []
     ignores: IgnoresConfiguration = IgnoresConfiguration()
+    headerMappings: Dict[str, str] = {}

config.schema.json

@@ -107,6 +107,16 @@
           "additionalProperties": false
         }
       }
+    },
+    "headerMappings": {
+      "description": "Mappings between header names from clangd and the canonical header, used when suggesting includes to add",
+      "type": "object",
+      "patternProperties": {
+        ".*": {
+          "description": "Mapping from header filename to canonical filename",
+          "type": "string"
+        }
+      }
     }
   },
   "additionalProperties": false

configs/chromium.json

@@ -43,9 +43,7 @@
       "ignores": {
         "add": {
           "headers": [
-            "absl/base/internal/inline_variable.h",
-            "absl/types/internal/optional.h",
-            "absl/types/optional.h"
+            "absl/base/internal/inline_variable.h"
           ]
         },
         "remove": {
@@ -270,5 +268,9 @@
         ]
       ]
     }
+  },
+  "headerMappings": {
+    "absl/types/optional.h": "third_party/abseil-cpp/absl/types/optional.h",
+    "third_party/abseil-cpp/absl/types/internal/optional.h": "third_party/abseil-cpp/absl/types/optional.h"
   }
 }

filter_include_changes.py

@@ -7,7 +7,8 @@
 import pathlib
 import re
 import sys
-from typing import List, Tuple
+from collections import defaultdict
+from typing import DefaultDict, Dict, List, Tuple
 
 from common import IgnoresConfiguration, IncludeChange
 from utils import load_config
@@ -27,9 +28,15 @@ def filter_changes(
     change_type_filter: IncludeChange = None,
     filter_generated_files=True,
     filter_mojom_headers=True,
+    header_mappings: Dict[str, str] = None,
 ):
     """Filter changes"""
 
+    # When header mappings are provided, we can cancel out suggestions from clangd where
+    # it suggests removing one include and adding another, when the pair is found in the
+    # mapping, since we know that means clangd is confused on which header to include
+    pending_changes: DefaultDict[str, Dict[str, Tuple[IncludeChange, int, int]]] = defaultdict(dict)
+
     for change_type_value, line, filename, header, *_ in changes:
         change_type = IncludeChange.from_value(change_type_value)
 
@@ -83,8 +90,38 @@ def filter_changes(
                 if ignore_edge or ignore_include:
                     continue
 
+        # If the header is in a provided header mapping, wait until the end to yield it
+        if header_mappings and header in header_mappings:
+            assert header not in pending_changes[filename]
+
+            # TODO - Includes inside of dependencies shouldn't be mapped since they can
+            #        access internal headers, and the mapped canonical header is from
+            #        the perspective of the project's root source directory
+            pending_changes[filename][header] = (change_type, line, *_)
+            continue
+
         yield (change_type_value, line, filename, header, *_)
 
+    if header_mappings:
+        inverse_header_mappings = {v: k for k, v in header_mappings.items()}
+
+        for filename in pending_changes:
+            for header in pending_changes[filename]:
+                change_type, line, *_ = pending_changes[filename][header]
+
+                if change_type is IncludeChange.ADD:
+                    # Look for a corresponding remove which would cancel out
+                    if header_mappings[header] in pending_changes[filename]:
+                        if pending_changes[filename][header][0] is IncludeChange.REMOVE:
+                            continue
+                elif change_type is IncludeChange.REMOVE and header in inverse_header_mappings:
+                    # Look for a corresponding add which would cancel out
+                    if inverse_header_mappings[header] in pending_changes[filename]:
+                        if pending_changes[filename][header][0] is IncludeChange.ADD:
+                            continue
+
+                yield (change_type.value, line, filename, header_mappings, *_)
+
 
 def main():
     parser = argparse.ArgumentParser(description="Filter include changes output")
@@ -127,10 +164,14 @@ def main():
     else:
         change_type_filter = None
 
+    config = None
     ignores = None
 
-    if args.config and not args.no_filter_ignores:
-        ignores = load_config(args.config).ignores
+    if args.config:
+        config = load_config(args.config)
+
+    if config and not args.no_filter_ignores:
+        ignores = config.ignores
 
     csv_writer = csv.writer(sys.stdout)
 
@@ -143,6 +184,7 @@ def main():
             change_type_filter=change_type_filter,
             filter_generated_files=not args.no_filter_generated_files,
             filter_mojom_headers=not args.no_filter_mojom_headers,
+            header_mappings=config.headerMappings if config else None,
         ):
             csv_writer.writerow(change)