pw_env_setup: add warning when using *.bat on Linux

Change-Id: I62da6ad0f14fd0563eee07c20b8fd78e38b53e28

activate.bat

@@ -1,3 +1,4 @@
+:<<"::WINDOWS_ONLY"
 @echo off
 :: Copyright 2020 The Pigweed Authors
 ::
@@ -12,6 +13,13 @@
 :: WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 :: License for the specific language governing permissions and limitations under
 :: the License.
+::WINDOWS_ONLY
+:; echo "ERROR: Attempting to run Windows .bat from a Unix/POSIX shell!"
+:; echo "Instead, run the following command."
+:; echo ""
+:; echo "    source ./activate.sh"
+:; echo ""
+:<<"::WINDOWS_ONLY"
 
 :: Activates a Pigweed development environment by setting the appropriate
 :: environment variables. bootstrap.bat must be run initially to install all
@@ -21,3 +29,4 @@
 set PW_SKIP_BOOTSTRAP=1
 call "%~dp0\bootstrap.bat"
 set PW_SKIP_BOOTSTRAP=
+::WINDOWS_ONLY

bootstrap.bat

@@ -1,3 +1,4 @@
+:<<"::WINDOWS_ONLY"
 @echo off
 :: Copyright 2020 The Pigweed Authors
 ::
@@ -12,6 +13,13 @@
 :: WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 :: License for the specific language governing permissions and limitations under
 :: the License.
+::WINDOWS_ONLY
+:; echo "ERROR: Attempting to run Windows .bat from a Unix/POSIX shell!"
+:; echo "Instead, run the following command."
+:; echo ""
+:; echo "    source ./bootstrap.sh"
+:; echo ""
+:<<"::WINDOWS_ONLY"
 
 :: Pigweed Windows environment setup.
 
@@ -86,3 +94,4 @@ set PW_CARGO_PACKAGE_FILES=%_PW_OLD_CARGO_PACKAGE_FILES%
 call "%shell_file%"
 
 :finish
+::WINDOWS_ONLY

pw_presubmit/py/pw_presubmit/pigweed_presubmit.py

@@ -299,6 +299,14 @@ if sys.platform != 'darwin':
 COPYRIGHT_FIRST_LINE = re.compile(
     r'^(#|//| \*|REM|::) Copyright 20\d\d The Pigweed Authors$')
 
+COPYRIGHT_FIRST_LINE_EXCEPTIONS = (
+    '#!',
+    '/*',
+    '@echo off',
+    '# -*-',
+    ':',
+)
+
 COPYRIGHT_LINES = tuple("""\
 
  Licensed under the Apache License, Version 2.0 (the "License"); you may not
@@ -340,13 +348,19 @@ def copyright_notice(ctx: PresubmitContext):
     for path in ctx.paths:
         _LOG.debug('Checking %s', path)
         with open(path) as file:
-            # Skip shebang and blank lines
             line = file.readline()
-            while line and (line.startswith(
-                ('#!', '/*', '@echo off', '# -*-')) or not line.strip()):
+            first_line = None
+            while line:
+                first_line = COPYRIGHT_FIRST_LINE.match(line)
+                if first_line:
+                    break
+
+                if (line.strip() and
+                        not line.startswith(COPYRIGHT_FIRST_LINE_EXCEPTIONS)):
+                    break
+
                 line = file.readline()
 
-            first_line = COPYRIGHT_FIRST_LINE.match(line)
             if not first_line:
                 _LOG.debug('%s: invalid first line %r', path, line)
                 errors.append(path)