From 1426e7879397804c2ec506ffaac17cde978c4723 Mon Sep 17 00:00:00 2001
From: Ivan Kravets <me@ikravets.com>
Date: Sat, 3 Oct 2015 15:38:33 +0100
Subject: [PATCH] Show valid environment names when user typed unknown values

---
 platformio/__init__.py     | 2 +-
 platformio/commands/run.py | 7 +++++--
 platformio/exception.py    | 6 +++---
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/platformio/__init__.py b/platformio/__init__.py
index 33f6ab52..e181eb57 100644
--- a/platformio/__init__.py
+++ b/platformio/__init__.py
@@ -1,7 +1,7 @@
 # Copyright (C) Ivan Kravets <me@ikravets.com>
 # See LICENSE for details.
 
-VERSION = (2, 3, 3)
+VERSION = (2, 3, "4.dev0")
 __version__ = ".".join([str(s) for s in VERSION])
 
 __title__ = "platformio"
diff --git a/platformio/commands/run.py b/platformio/commands/run.py
index daf6ae41..8fdf485b 100644
--- a/platformio/commands/run.py
+++ b/platformio/commands/run.py
@@ -36,9 +36,12 @@ def cli(ctx, environment, target, upload_port,  # pylint: disable=R0913,R0914
         if not config.sections():
             raise exception.ProjectEnvsNotAvailable()
 
-        unknown = set(environment) - set([s[4:] for s in config.sections()])
+        known = set([s[4:] for s in config.sections()
+                     if s.startswith("env:")])
+        unknown = set(environment) - known
         if unknown:
-            raise exception.UnknownEnvNames(", ".join(unknown))
+            raise exception.UnknownEnvNames(
+                ", ".join(unknown), ", ".join(known))
 
         # clean obsolete .pioenvs dir
         if not disable_auto_clean:
diff --git a/platformio/exception.py b/platformio/exception.py
index 84b6aca0..940d41d2 100644
--- a/platformio/exception.py
+++ b/platformio/exception.py
@@ -104,17 +104,17 @@ class UnsupportedArchiveType(PlatformioException):
 
 class ProjectEnvsNotAvailable(PlatformioException):
 
-    MESSAGE = "Please setup environments in `platformio.ini` file."
+    MESSAGE = "Please setup environments in `platformio.ini` file"
 
 
 class InvalidEnvName(PlatformioException):
 
-    MESSAGE = "Invalid environment '%s'. The name must start " "with 'env:'."
+    MESSAGE = "Invalid environment '%s'. The name must start with 'env:'"
 
 
 class UnknownEnvNames(PlatformioException):
 
-    MESSAGE = "Unknown environment names '%s'."
+    MESSAGE = "Unknown environment names '%s'. Valid names are '%s'"
 
 
 class GetSerialPortsError(PlatformioException):