From f5406ef454662b98df107775d18ff71ae6849618 Mon Sep 17 00:00:00 2001
From: Seth Michael Larson <seth@python.org>
Date: Wed, 1 May 2024 09:47:41 -0500
Subject: gh-116122: Add SBOM generation to PCbuild/build.bat (GH-116138)

(cherry picked from commit 72dae53e09a5344bf4922d934a34a2fa48a11c86)

Co-authored-by: Seth Michael Larson <seth@python.org>
---
 PCbuild/regen.targets        | 15 +++++++++++++--
 Tools/build/generate_sbom.py | 21 ++++++++++++++++++---
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/PCbuild/regen.targets b/PCbuild/regen.targets
index 645656c..49a2266 100644
--- a/PCbuild/regen.targets
+++ b/PCbuild/regen.targets
@@ -30,11 +30,15 @@
     </_TokenOutputs>
     <_KeywordSources Include="$(PySourcePath)Grammar\python.gram;$(PySourcePath)Grammar\Tokens" />
     <_KeywordOutputs Include="$(PySourcePath)Lib\keyword.py" />
+    <_SbomSources Include="$(PySourcePath)PCbuild\get_externals.bat" />
+    <_SbomOutputs Include="$(PySourcePath)Misc\externals.spdx.json;$(PySourcePath)Misc\sbom.spdx.json">
+      <Format>json</Format>
+    </_SbomOutputs>
   </ItemGroup>
 
   <Target Name="_TouchRegenSources" Condition="$(ForceRegen) == 'true'">
     <Message Text="Touching source files to force regeneration" Importance="high" />
-    <Touch Files="@(_PegenSources);@(_ASTSources);@(_OpcodeSources);@(_TokenSources);@(_KeywordOutputs)"
+    <Touch Files="@(_PegenSources);@(_ASTSources);@(_OpcodeSources);@(_TokenSources);@(_KeywordOutputs);@(_SbomSources)"
            AlwaysCreate="False" />
   </Target>
 
@@ -89,9 +93,16 @@
           WorkingDirectory="$(PySourcePath)" />
   </Target>
 
+  <Target Name="_RegenSbom"
+          DependsOnTargets="FindPythonForBuild"
+          Inputs="@(_SbomSources)"
+          Outputs="@(_SbomOutputs)">
+    <Exec Command='$(PythonForBuild) "$(PySourcePath)Tools\build\generate_sbom.py"'/>
+  </Target>
+
   <Target Name="Regen"
           Condition="$(Configuration) != 'PGUpdate'"
-          DependsOnTargets="_TouchRegenSources;_RegenPegen;_RegenAST_H;_RegenOpcodes;_RegenTokens;_RegenKeywords;_RegenGlobalObjects">
+          DependsOnTargets="_TouchRegenSources;_RegenPegen;_RegenAST_H;_RegenOpcodes;_RegenTokens;_RegenKeywords;_RegenGlobalObjects;_RegenSbom">
     <Message Text="Generated sources are up to date" Importance="high" />
   </Target>
 
diff --git a/Tools/build/generate_sbom.py b/Tools/build/generate_sbom.py
index 5c1851f..258b58c 100644
--- a/Tools/build/generate_sbom.py
+++ b/Tools/build/generate_sbom.py
@@ -4,13 +4,13 @@ import re
 import hashlib
 import json
 import glob
-import pathlib
+from pathlib import Path, PurePosixPath, PureWindowsPath
 import subprocess
 import sys
 import urllib.request
 import typing
 
-CPYTHON_ROOT_DIR = pathlib.Path(__file__).parent.parent.parent
+CPYTHON_ROOT_DIR = Path(__file__).parent.parent.parent
 
 # Before adding a new entry to this list, double check that
 # the license expression is a valid SPDX license expression:
@@ -119,9 +119,16 @@ def filter_gitignored_paths(paths: list[str]) -> list[str]:
     # 1 means matches, 0 means no matches.
     assert git_check_ignore_proc.returncode in (0, 1)
 
+    # Paths may or may not be quoted, Windows quotes paths.
+    git_check_ignore_re = re.compile(r"^::\s+(\"([^\"]+)\"|(.+))\Z")
+
     # Return the list of paths sorted
     git_check_ignore_lines = git_check_ignore_proc.stdout.decode().splitlines()
-    return sorted([line.split()[-1] for line in git_check_ignore_lines if line.startswith("::")])
+    git_check_not_ignored = []
+    for line in git_check_ignore_lines:
+        if match := git_check_ignore_re.fullmatch(line):
+            git_check_not_ignored.append(match.group(2) or match.group(3))
+    return sorted(git_check_not_ignored)
 
 
 def get_externals() -> list[str]:
@@ -238,12 +245,20 @@ def create_source_sbom() -> None:
             )
 
             for path in paths:
+
+                # Normalize the filename from any combination of slashes.
+                path = str(PurePosixPath(PureWindowsPath(path)))
+
                 # Skip directories and excluded files
                 if not (CPYTHON_ROOT_DIR / path).is_file() or path in exclude:
                     continue
 
                 # SPDX requires SHA1 to be used for files, but we provide SHA256 too.
                 data = (CPYTHON_ROOT_DIR / path).read_bytes()
+                # We normalize line-endings for consistent checksums.
+                # This is a rudimentary check for binary files.
+                if b"\x00" not in data:
+                    data = data.replace(b"\r\n", b"\n")
                 checksum_sha1 = hashlib.sha1(data).hexdigest()
                 checksum_sha256 = hashlib.sha256(data).hexdigest()
 
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