From d7e2d05f60fb2c10770eb6d0c364d84c3d5cc5d4 Mon Sep 17 00:00:00 2001
From: Ivan Kravets <me@ikravets.com>
Date: Wed, 20 Mar 2019 18:49:20 +0200
Subject: [PATCH] Fix error with conflicting declaration of a prototype
 (Arduino sketch preprocessor)

---
 HISTORY.rst                         |  1 +
 platformio/builder/tools/piomisc.py | 13 ++++++++++---
 tests/ino2cpp/basic/basic.ino       |  8 ++++++++
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/HISTORY.rst b/HISTORY.rst
index 32e2aa8d..f59d36aa 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -7,6 +7,7 @@ PlatformIO 3.0
 3.6.6 (2019-??-??)
 ~~~~~~~~~~~~~~~~~~
 
+* Fixed error with conflicting declaration of a prototype (Arduino sketch preprocessor)
 * Fixed "FileExistsError" when `platformio ci <https://docs.platformio.org/en/latest/userguide/cmd_ci.html>`__ command is used in pair with ``--keep-build-dir`` option
 
 3.6.5 (2019-03-07)
diff --git a/platformio/builder/tools/piomisc.py b/platformio/builder/tools/piomisc.py
index be030f39..c2173bd2 100644
--- a/platformio/builder/tools/piomisc.py
+++ b/platformio/builder/tools/piomisc.py
@@ -33,10 +33,10 @@ class InoToCPPConverter(object):
     PROTOTYPE_RE = re.compile(
         r"""^(
         (?:template\<.*\>\s*)?      # template
-        ([a-z_\d\&]+\*?\s+){1,2}      # return type
+        ([a-z_\d\&]+\*?\s+){1,2}    # return type
         ([a-z_\d]+\s*)              # name of prototype
         \([a-z_,\.\*\&\[\]\s\d]*\)  # arguments
-        )\s*\{                      # must end with {
+        )\s*(\{|;)                  # must end with `{` or `;`
         """, re.X | re.M | re.I)
     DETECTMAIN_RE = re.compile(r"void\s+(setup|loop)\s*\(", re.M | re.I)
     PROTOPTRS_TPLRE = r"\([^&\(]*&(%s)[^\)]*\)"
@@ -162,7 +162,14 @@ class InoToCPPConverter(object):
         if not prototypes:
             return contents
 
-        prototype_names = set([m.group(3).strip() for m in prototypes])
+        # skip already declared prototypes
+        declared = set(
+            m.group(1).strip() for m in prototypes if m.group(4) == ";")
+        prototypes = [
+            m for m in prototypes if m.group(1).strip() not in declared
+        ]
+
+        prototype_names = set(m.group(3).strip() for m in prototypes)
         split_pos = prototypes[0].start()
         match_ptrs = re.search(
             self.PROTOPTRS_TPLRE % ("|".join(prototype_names)),
diff --git a/tests/ino2cpp/basic/basic.ino b/tests/ino2cpp/basic/basic.ino
index 0c5d7511..fcec8edd 100644
--- a/tests/ino2cpp/basic/basic.ino
+++ b/tests/ino2cpp/basic/basic.ino
@@ -49,4 +49,12 @@ void fooCallback(){
 
 }
 
+extern "C" {
+void some_extern(const char *fmt, ...);
+};
+
+void some_extern(const char *fmt, ...) {
+
+}
+
 // юнікод