Fix compile_commands.json having incorrect include paths for clean builds when a variant dir is used, duplicate=0, and a relative CPPPATH is used in a child SConscript

CHANGES.txt

@@ -94,6 +94,10 @@ RELEASE  VERSION/DATE TO BE FILLED IN LATER
     - Update documentation for linking-related construction variables.
       Add a few more live links.
 
+  From Will Toohey:
+    - Fix compile_commands.json having incorrect include paths for clean builds
+      when a variant dir is used, duplicate=0, and a relative CPPPATH is used in
+      a child SConscript.
 
 RELEASE 4.10.1 - Sun, 16 Nov 2025 10:51:57 -0700
 

RELEASE.txt

@@ -51,6 +51,9 @@ FIXES
   directory for each writer before doing the move, instead of depending
   on a one-time uuid to make a path to the file.
 
+- Fix compile_commands.json having incorrect include paths for clean builds when a
+  variant dir is used, duplicate=0, and a relative CPPPATH is used in a child SConscript.
+
 IMPROVEMENTS
 ------------
 

SCons/Node/FS.py

@@ -3305,7 +3305,6 @@ def built(self) -> None:
             self._specific_sources = False
             self._labspath = ""
             self._save_str()
-            self.cwd = None
 
             self.scanner_paths = None
 

test/CompilationDatabase/fixture/SConstruct_variant

@@ -49,3 +49,5 @@ env.Program('build2/main', 'build2/test_main.c')
 env.VariantDir('build3','src', duplicate=0)
 env.InstallAs('build3/test_main_copy.c', 'src/test_main.c')
 env.Program('build3/main', 'build3/test_main_copy.c')
+
+SConscript('src/SConscript_cpppath', variant_dir='build4', duplicate=0, exports={'env': env})

test/CompilationDatabase/fixture/src_SConscript_cpppath

@@ -0,0 +1,2 @@
+Import('env')
+env.Object('test_main.c', CPPPATH=['inc'])

test/CompilationDatabase/variant_dir.py

@@ -40,6 +40,7 @@
 
 test.verbose_set(1)
 test.file_fixture('fixture/SConstruct_variant', 'SConstruct')
+test.file_fixture('fixture/src_SConscript_cpppath', 'src/SConscript_cpppath')
 test.file_fixture('test_main.c', 'src/test_main.c')
 test.run()
 
@@ -84,6 +85,12 @@
         "directory": "%(workdir)s",
         "file": "%(variant3_src_file)s",
         "output": "%(output3_file)s"
+    },
+    {
+        "command": "%(exe)s mygcc.py cc -o %(output4_file)s -c -I%(inc_build4)s -I%(inc_src)s %(src_file)s",
+        "directory": "%(workdir)s",
+        "file": "%(src_file)s",
+        "output": "%(output4_file)s"
     }
 ]
 """ % {'exe': sys.executable,
@@ -92,8 +99,11 @@
         'output_file': os.path.join('build', 'test_main.o'),
         'output2_file': os.path.join('build2', 'test_main.o'),
         'output3_file': os.path.join('build3', 'test_main_copy.o'),
+        'output4_file': os.path.join('build4', 'test_main.o'),
         'variant_src_file': os.path.join('build', 'test_main.c'),
-        'variant3_src_file': os.path.join('build3', 'test_main_copy.c')
+        'variant3_src_file': os.path.join('build3', 'test_main_copy.c'),
+        'inc_build4': os.path.join('build4', 'inc'),
+        'inc_src': os.path.join('src', 'inc'),
         }
 
 if sys.platform == 'win32':
@@ -122,6 +132,12 @@
         "directory": "%(workdir)s",
         "file": "%(abs_variant3_src_file)s",
         "output": "%(abs_output3_file)s"
+    },
+    {
+        "command": "%(exe)s mygcc.py cc -o %(output4_file)s -c -I%(inc_build4)s -I%(inc_src)s %(src_file)s",
+        "directory": "%(workdir)s",
+        "file": "%(abs_src_file)s",
+        "output": "%(abs_output4_file)s"
     }
 ]
 """ % {'exe': sys.executable,
@@ -131,12 +147,16 @@
         'abs_output_file': os.path.join(test.workdir, 'build', 'test_main.o'),
         'abs_output2_file': os.path.join(test.workdir, 'build2', 'test_main.o'),
         'abs_output3_file': os.path.join(test.workdir, 'build3', 'test_main_copy.o'),
+        'abs_output4_file': os.path.join(test.workdir, 'build4', 'test_main.o'),
         'output_file': os.path.join('build', 'test_main.o'),
         'output2_file': os.path.join('build2', 'test_main.o'),
         'output3_file': os.path.join('build3', 'test_main_copy.o'),
+        'output4_file': os.path.join('build4', 'test_main.o'),
         'abs_variant3_src_file': os.path.join(test.workdir, 'build3', 'test_main_copy.c'),
         'variant_src_file': os.path.join('build', 'test_main.c'),
-        'variant3_src_file': os.path.join('build3', 'test_main_copy.c')
+        'variant3_src_file': os.path.join('build3', 'test_main_copy.c'),
+        'inc_build4': os.path.join('build4', 'inc'),
+        'inc_src': os.path.join('src', 'inc'),
         }
 
 if sys.platform == 'win32':

test/fixture/mygcc.py

@@ -33,7 +33,7 @@ def fake_gcc():
         sys.exit(0)
 
     compiler = sys.argv[1].encode('utf-8')
-    opts, args = getopt.getopt(sys.argv[2:], 'co:xf:K:')
+    opts, args = getopt.getopt(sys.argv[2:], 'co:xf:K:I:')
     for opt, arg in opts:
         if opt == '-o':
             out = arg