bitbake: ast/event/utils: Improve tracebacks to include file and line numbers more correctly

Currently bitbake tracebacks can have places where the line numbers are
inaccurate and filenames may be missing. These changes start to try and
correct this.

The only way I could find to correct line numbers was to compile as a
python ast, tweak the line numbers then compile to bytecode. I'm open
to better ways of doing this if anyone knows of any.

This does mean passing a few more parameters into functions, and putting
more data into the data store about functions (i.e. their filenames
and line numbers) but the improvement in debugging is more than worthwhile).

Before:
----------------
ERROR: Execution of event handler 'run_buildstats' failed
Traceback (most recent call last):
  File "run_buildstats(e)", line 43, in run_buildstats(e=<bb.build.TaskStarted object at 0x7f7b7c57a590>)
NameError: global name 'notexist' is not defined

ERROR: Build of do_patch failed
ERROR: Traceback (most recent call last):
  File "/media/build1/poky/bitbake/lib/bb/build.py", line 560, in exec_task
    return _exec_task(fn, task, d, quieterr)
  File "/media/build1/poky/bitbake/lib/bb/build.py", line 497, in _exec_task
    event.fire(TaskStarted(task, logfn, flags, localdata), localdata)
  File "/media/build1/poky/bitbake/lib/bb/event.py", line 170, in fire
    fire_class_handlers(event, d)
  File "/media/build1/poky/bitbake/lib/bb/event.py", line 109, in fire_class_handlers
    execute_handler(name, handler, event, d)
  File "/media/build1/poky/bitbake/lib/bb/event.py", line 81, in execute_handler
    ret = handler(event)
  File "run_buildstats(e)", line 43, in run_buildstats
NameError: global name 'notexist' is not defined

----------------

After:
----------------
ERROR: Execution of event handler 'run_buildstats' failed
Traceback (most recent call last):
  File "/media/build1/poky/meta/classes/buildstats.bbclass", line 143, in run_buildstats(e=<bb.build.TaskStarted object at 0x7efe89284e10>):
         if isinstance(e, bb.build.TaskStarted):
    >        trigger = notexist
             pn = d.getVar("PN", True)
NameError: global name 'notexist' is not defined

ERROR: Build of do_package failed
ERROR: Traceback (most recent call last):
  File "/media/build1/poky/bitbake/lib/bb/build.py", line 560, in exec_task
    return _exec_task(fn, task, d, quieterr)
  File "/media/build1/poky/bitbake/lib/bb/build.py", line 497, in _exec_task
    event.fire(TaskStarted(task, logfn, flags, localdata), localdata)
  File "/media/build1/poky/bitbake/lib/bb/event.py", line 170, in fire
    fire_class_handlers(event, d)
  File "/media/build1/poky/bitbake/lib/bb/event.py", line 109, in fire_class_handlers
    execute_handler(name, handler, event, d)
  File "/media/build1/poky/bitbake/lib/bb/event.py", line 81, in execute_handler
    ret = handler(event)
  File "/media/build1/poky/meta/classes/buildstats.bbclass", line 143, in run_buildstats
    trigger = notexist
NameError: global name 'notexist' is not defined
----------------

(Bitbake rev: 1ff860960919ff6f8097138bc68de85bcb5f88b0)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/bitbake/lib/bb/event.py b/bitbake/lib/bb/event.py
index ec25ce77fb..bd2b0a4b05 100644
--- a/bitbake/lib/bb/event.py
+++ b/bitbake/lib/bb/event.py
@@ -177,7 +177,7 @@ def fire_from_worker(event, d):
     fire_ui_handlers(event, d)
 
 noop = lambda _: None
-def register(name, handler, mask=None):
+def register(name, handler, mask=None, filename=None, lineno=None):
     """Register an Event handler"""
 
     # already registered
@@ -189,7 +189,13 @@ def register(name, handler, mask=None):
         if isinstance(handler, basestring):
             tmp = "def %s(e):\n%s" % (name, handler)
             try:
-                code = compile(tmp, "%s(e)" % name, "exec")
+                import ast
+                if filename is None:
+                    filename = "%s(e)" % name
+                code = compile(tmp, filename, "exec", ast.PyCF_ONLY_AST)
+                if lineno is not None:
+                    ast.increment_lineno(code, lineno-1)
+                code = compile(code, filename, "exec")
             except SyntaxError:
                 logger.error("Unable to register event handler '%s':\n%s", name,
                              ''.join(traceback.format_exc(limit=0)))