Fixed handling of `-include` flag // Resolve #4683

HISTORY.rst

@@ -18,6 +18,8 @@ PlatformIO Core 6
 6.1.9 (2023-??-??)
 ~~~~~~~~~~~~~~~~~~
 
+* Rectified a regression bug that occurred when the ``-include`` flag was passed via the `build_flags <https://docs.platformio.org/en/latest/projectconf/sections/env/options/build/build_flags.html>`__ option as a relative path and subsequently expanded (`issue #4683 <https://github.com/platformio/platformio-core/issues/4683>`_)
+
 6.1.8 (2023-07-05)
 ~~~~~~~~~~~~~~~~~~
 

platformio/builder/tools/piobuild.py

@@ -201,15 +201,13 @@ def ParseFlagsExtended(env, flags):  # pylint: disable=too-many-branches
     for k in ("CPPPATH", "LIBPATH"):
         for i, p in enumerate(result.get(k, [])):
             p = env.subst(p)
-            if os.path.isdir(p):
-                result[k][i] = os.path.abspath(p)
+            result[k][i] = p if os.path.isabs(p) else env.Dir(f"#{p}")
 
     # fix relative path for "-include"
     for i, f in enumerate(result.get("CCFLAGS", [])):
         if isinstance(f, tuple) and f[0] == "-include":
             p = env.subst(f[1].get_path())
-            if os.path.exists(p):
-                result["CCFLAGS"][i] = (f[0], os.path.abspath(p))
+            result["CCFLAGS"][i] = (f[0], p if os.path.isabs(p) else env.File(f"#{p}"))
 
     return result
 

tests/commands/test_run.py

@@ -22,7 +22,10 @@ def test_generic_build(clirunner, validate_cliresult, tmpdir):
         ("-D TEST_INT=13", "-DTEST_INT=13"),
         ("-DTEST_SINGLE_MACRO", "-DTEST_SINGLE_MACRO"),
         ('-DTEST_STR_SPACE="Andrew Smith"', '"-DTEST_STR_SPACE=Andrew Smith"'),
+        ("-Iinclude", "-Iinclude"),
+        ("-include cpppath-include.h", "cpppath-include.h"),
         ("-Iextra_inc", "-Iextra_inc"),
+        ("-Inon-existing-dir", "-Inon-existing-dir"),
         (
             "-include $PROJECT_DIR/lib/component/component-forced-include.h",
             "component-forced-include.h",
@@ -103,12 +106,22 @@ projenv.Append(CPPDEFINES="POST_SCRIPT_MACRO")
 #error "I_AM_FORCED_COMPONENT_INCLUDE"
 #endif
 
+#ifndef I_AM_FORCED_CPPPATH_INCLUDE
+#error "I_AM_FORCED_CPPPATH_INCLUDE"
+#endif
+
 #ifdef COMMENTED_MACRO
 #error "COMMENTED_MACRO"
 #endif
 
 int main() {
 }
+"""
+    )
+
+    tmpdir.mkdir("include").join("cpppath-include.h").write(
+        """
+#define I_AM_FORCED_CPPPATH_INCLUDE
 """
     )
     component_dir = tmpdir.mkdir("lib").mkdir("component")