BBHandler/ConfHandler: Improve multiline comment handling

[Richard Purdie <richard.purdie@linuxfoundation.org>]

Faced with an expression like:

 # Some comment \
 FOO = "bar"

what should bitbake do? Technically, the \ character means its multiline and
currently the code treats this as a continuation of the comment. This can
surprise some people and is not intuitive.

This patch makes bitbake simply error and asks the user to be clearer
about what they mean.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
---
diff --git a/bitbake/lib/bb/parse/parse_py/BBHandler.py b/bitbake/lib/bb/parse/parse_py/BBHandler.py
index 2ee8ebd..58049bd 100644
--- a/bitbake/lib/bb/parse/parse_py/BBHandler.py
+++ b/bitbake/lib/bb/parse/parse_py/BBHandler.py
@@ -200,7 +200,10 @@ def feeder(lineno, s, fn, root, statements):
 
     if s and s[0] == '#':
         if len(__residue__) != 0 and __residue__[0][0] != "#":
-            bb.error("There is a comment on line %s of file %s (%s) which is in the middle of a multiline expression.\nBitbake used to ignore these but no longer does so, please fix your metadata as errors are likely as a result of this change." % (lineno, fn, s))
+            bb.fatal("There is a comment on line %s of file %s (%s) which is in the middle of a multiline expression.\nBitbake used to ignore these but no longer does so, please fix your metadata as errors are likely as a result of this change." % (lineno, fn, s))
+
+    if len(__residue__) != 0 and __residue__[0][0] == "#" and s[0] != "#":
+        bb.fatal("There is a confusing multiline, partially commented expression on line %s of file %s (%s).\nPlease clarify whether this is all a comment or should be parsed." % (lineno, fn, s))
 
     if s and s[-1] == '\\':
         __residue__.append(s[:-1])
diff --git a/bitbake/lib/bb/parse/parse_py/ConfHandler.py b/bitbake/lib/bb/parse/parse_py/ConfHandler.py
index dbc6776..9b09c9f 100644
--- a/bitbake/lib/bb/parse/parse_py/ConfHandler.py
+++ b/bitbake/lib/bb/parse/parse_py/ConfHandler.py
@@ -98,15 +98,22 @@ def handle(fn, data, include):
     while True:
         lineno = lineno + 1
         s = f.readline()
-        if not s: break
+        if not s:
+            break
         w = s.strip()
-        if not w: continue          # skip empty lines
+        # skip empty lines
+        if not w:
+            continue
         s = s.rstrip()
-        if s[0] == '#': continue    # skip comments
         while s[-1] == '\\':
             s2 = f.readline().strip()
             lineno = lineno + 1
+            if s2 and s[0] == "#" and s2[0] != "#":
+                bb.fatal("There is a confusing multiline, partially commented expression on line %s of file %s (%s).\nPlease clarify whether this is all a comment or should be parsed." % (lineno, fn, s))
             s = s[:-1] + s2
+        # skip comments
+        if s[0] == '#':
+            continue
         feeder(lineno, s, fn, statements)
 
     # DONE WITH PARSING... time to evaluate