From abf63048187c2ed28429dceeb072793e6f7c6252 Mon Sep 17 00:00:00 2001
From: Ivan Kravets <me@ikravets.com>
Date: Tue, 17 May 2022 16:03:33 +0300
Subject: [PATCH] Fixed an issue when using "Interpolation of Values" and
 merging str+int options // Resolve #4271

---
 HISTORY.rst                  |  6 ++++--
 platformio/project/config.py |  2 +-
 tests/project/test_config.py | 16 ++++++++++++----
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/HISTORY.rst b/HISTORY.rst
index bb35be2c..c8d278c2 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -3,6 +3,7 @@ Release Notes
 
 .. |PIOCONF| replace:: `"platformio.ini" <https://docs.platformio.org/en/latest/projectconf.html>`__ configuration file
 .. |LDF| replace:: `LDF <https://docs.platformio.org/en/latest/librarymanager/ldf.html>`__
+.. |INTERPOLATION| replace:: `Interpolation of Values <https://docs.platformio.org/en/latest/projectconf/interpolation.html>`__
 
 .. _release_notes_6:
 
@@ -15,7 +16,8 @@ PlatformIO Core 6
 ~~~~~~~~~~~~~~~~~~
 
 * Improved support for the renamed configuration options (`issue #4270 <https://github.com/platformio/platformio-core/issues/4270>`_)
-* Fixed an issue when calling built-in `pio device monitor <https://docs.platformio.org/en/latest/core/userguide/device/cmd_monitor.html#filters>`__ filter
+* Fixed an issue when calling the built-in `pio device monitor <https://docs.platformio.org/en/latest/core/userguide/device/cmd_monitor.html#filters>`__ filter
+* Fixed an issue when using |INTERPOLATION| and merging str+int options (`issue #4271 <https://github.com/platformio/platformio-core/issues/4271>`_)
 
 6.0.0 (2022-05-16)
 ~~~~~~~~~~~~~~~~~~
@@ -98,7 +100,7 @@ Please check the `Migration guide from 5.x to 6.0 <https://docs.platformio.org/e
 
 * **Project Configuration**
 
-  - Extended `Interpolation of Values <https://docs.platformio.org/en/latest/projectconf/interpolation.html>`__  with ``${this}`` pattern (`issue #3953 <https://github.com/platformio/platformio-core/issues/3953>`_)
+  - Extended |INTERPOLATION| with ``${this}`` pattern (`issue #3953 <https://github.com/platformio/platformio-core/issues/3953>`_)
   - Embed environment name of the current section in the |PIOCONF| using ``${this.__env__}`` pattern
   - Renamed the "src_build_flags" project configuration option to the `build_src_flags <https://docs.platformio.org/en/latest/projectconf/section_env_build.html#build-src-flags>`__
   - Renamed the "src_filter" project configuration option to the `build_src_filter <https://docs.platformio.org/en/latest/projectconf/section_env_build.html#build-src-filter>`__
diff --git a/platformio/project/config.py b/platformio/project/config.py
index 0a4c6ed1..999827d5 100644
--- a/platformio/project/config.py
+++ b/platformio/project/config.py
@@ -330,7 +330,7 @@ class ProjectConfigBase(object):
             )
         if isinstance(value, list):
             return "\n".join(value)
-        return value
+        return str(value)
 
     def get(self, section, option, default=MISSING):
         value = None
diff --git a/tests/project/test_config.py b/tests/project/test_config.py
index aa948f71..964c0e67 100644
--- a/tests/project/test_config.py
+++ b/tests/project/test_config.py
@@ -85,6 +85,7 @@ build_flags =
     -Wl,--gc-sections
     ${custom.lib_flags}
     ${custom.debug_flags}
+    -D SERIAL_BAUD_RATE=${this.monitor_speed}
 lib_install = 574
 
 [env:extra_2]
@@ -297,9 +298,9 @@ def test_getraw_value(config):
     # known
     assert config.getraw("env:base", "targets") == ""
     assert config.getraw("env:extra_1", "lib_deps") == "574"
-    assert (
-        config.getraw("env:extra_1", "build_flags")
-        == "\n-fdata-sections\n-Wl,--gc-sections\n-lc -lm\n-D DEBUG=1"
+    assert config.getraw("env:extra_1", "build_flags") == (
+        "\n-fdata-sections\n-Wl,--gc-sections\n"
+        "-lc -lm\n-D DEBUG=1\n-D SERIAL_BAUD_RATE=9600"
     )
 
     # extended
@@ -329,6 +330,7 @@ def test_get_value(config):
         "-Wl,--gc-sections",
         "-lc -lm",
         "-D DEBUG=1",
+        "-D SERIAL_BAUD_RATE=9600",
     ]
     assert config.get("env:extra_2", "build_flags") == ["-Og"]
     assert config.get("env:extra_2", "monitor_speed") == 9600
@@ -390,7 +392,13 @@ def test_items(config):
     assert config.items(env="extra_1") == [
         (
             "build_flags",
-            ["-fdata-sections", "-Wl,--gc-sections", "-lc -lm", "-D DEBUG=1"],
+            [
+                "-fdata-sections",
+                "-Wl,--gc-sections",
+                "-lc -lm",
+                "-D DEBUG=1",
+                "-D SERIAL_BAUD_RATE=9600",
+            ],
         ),
         ("lib_install", ["574"]),
         ("monitor_speed", 9600),