utils: better_compile(): Fix line number when report errors

Fixed:
- Add an error line in base.bbclass, e.g.:
  15
  16 def oe_import(d):
  17     import sys
  18     Compile error
  19     bbpath = d.getVar("BBPATH").split(":")
  [snip]

  Note the "Compile error" line, I added it for reporting errors.

  $ bitbake -p
  ERROR: Error in compiling python function in /buildarea1/lyang1/poky/meta/classes/base.bbclass, line 15:

  The code lines resulting in this error were:
       0014:    import oe.data
       0015:    for toimport in oe.data.typed_value("OE_IMPORTS", d):
       0016:        imported = __import__(toimport)
       0017:        inject(toimport.split(".", 1)[0], imported)
   *** 0018:
       0019:    return ""
       0020:
  SyntaxError: invalid syntax (base.bbclass, line 18)

  There are 2 problems:
  - The "line 15" is incorrect, it is a blank line, not the error line.
  - The "*** 0018" points to incorrect position.

  These two problems would mislead people a lot sometimes.

- Now fix it to:
  $ bitbake -p
  ERROR: Error in compiling python function in /buildarea1/lyang1/poky/meta/classes/base.bbclass, line 18:

  The code lines resulting in this error were:
       0001:def oe_import(d):
       0002:    import sys
   *** 0003:    Compile error
       0004:    bbpath = d.getVar("BBPATH").split(":")
                [snip]
  SyntaxError: invalid syntax (base.bbclass, line 18)

Please see comments in the code for more details on how it is fixed.

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/bb/utils.py b/lib/bb/utils.py
index 3b0c9599c..13bb5f2a0 100644
--- a/lib/bb/utils.py
+++ b/lib/bb/utils.py
@@ -318,10 +318,13 @@ def better_compile(text, file, realfile, mode = "exec", lineno = 0):
         error = []
         # split the text into lines again
         body = text.split('\n')
-        error.append("Error in compiling python function in %s, line %s:\n" % (realfile, lineno))
+        error.append("Error in compiling python function in %s, line %s:\n" % (realfile, e.lineno))
         if hasattr(e, "lineno"):
             error.append("The code lines resulting in this error were:")
-            error.extend(_print_trace(body, e.lineno))
+            # e.lineno: line's position in reaflile
+            # lineno: function name's "position -1" in realfile
+            # e.lineno - lineno: line's relative position in function
+            error.extend(_print_trace(body, e.lineno - lineno))
         else:
             error.append("The function causing this error was:")
             for line in body: