Now that we don't have to worry about XPCShellErrorReporter being invoked at
weird times, we can get rid of this nastiness - though it unfortunately means
getting rid of one of my best comments in the tree. :-(
The -*- file variable lines -*- establish per-file settings that Emacs will
pick up. This patch makes the following changes to those lines (and touches
nothing else):
- Never set the buffer's mode.
Years ago, Emacs did not have a good JavaScript mode, so it made sense
to use Java or C++ mode in .js files. However, Emacs has had js-mode for
years now; it's perfectly serviceable, and is available and enabled by
default in all major Emacs packagings.
Selecting a mode in the -*- file variable line -*- is almost always the
wrong thing to do anyway. It overrides Emacs's default choice, which is
(now) reasonable; and even worse, it overrides settings the user might
have made in their '.emacs' file for that file extension. It's only
useful when there's something specific about that particular file that
makes a particular mode appropriate.
- Correctly propagate settings that establish the correct indentation
level for this file: c-basic-offset and js2-basic-offset should be
js-indent-level. Whatever value they're given should be preserved;
different parts of our tree use different indentation styles.
- We don't use tabs in Mozilla JS code. Always set indent-tabs-mode: nil.
Remove tab-width: settings, at least in files that don't contain tab
characters.
- Remove js2-mode settings that belong in the user's .emacs file, like
js2-skip-preprocessor-directives.
XPCShell currently overrides all the JSContexts whose creation it observes with
its own custom error reporter. This reporter does all sorts of funny things which
we try to clean up for the most part. But there are a few very intricate
considerations at play.
First, the old xpcshell error reporter does some mumbo jumbo with the
XPCCallContext stack to try to guess whether some other code might catch the
exception. This is total garbage on a number of fronts, particularly because
the XPCCallContext stack has no concept of saved frame chains, nested event
loops, sandbox boundaries, origin boundaries, or any of the myriad of
complicating factors that determine whether or not an exception will propagate.
So we get rid of it. But this causes some crazy debugger tests to fail, because
they rely on an exception from uriloader/exthandler/nsHandlerService.js getting
squelched, and can't handle anybody reporting errors to the console service at
the particular moment of contortionism when the exception is raised. So we need
to introduce an explicit mechanism to disable the error reporter here to keep
things running.
Second, we have to be very careful about tracking the return status of the
xpcshell binary. The old code would simply flag an error code if the error
handler was invoked, and we can mostly continue to do that. But there are some
complications. See the comments.
Finally, we don't anything analogous in XPCShellEnvironment, because I have
patches in bug 889714 to remove its state-dependence on the error reporter.
I'll switch it to SystemErrorReporter in that bug.
XPCShell currently overrides all the JSContexts whose creation it observes with
its own custom error reporter. This reporter does all sorts of funny things which
we try to clean up for the most part. But there are a few very intricate
considerations at play.
First, the old xpcshell error reporter does some mumbo jumbo with the
XPCCallContext stack to try to guess whether some other code might catch the
exception. This is total garbage on a number of fronts, particularly because
the XPCCallContext stack has no concept of saved frame chains, nested event
loops, sandbox boundaries, origin boundaries, or any of the myriad of
complicating factors that determine whether or not an exception will propagate.
So we get rid of it. But this causes some crazy debugger tests to fail, because
they rely on an exception from uriloader/exthandler/nsHandlerService.js getting
squelched, and can't handle anybody reporting errors to the console service at
the particular moment of contortionism when the exception is raised. So we need
to introduce an explicit mechanism to disable the error reporter here to keep
things running.
Second, we have to be very careful about tracking the return status of the
xpcshell binary. The old code would simply flag an error code if the error
handler was invoked, and we can mostly continue to do that. But there are some
complications. See the comments.
Finally, we don't anything analogous in XPCShellEnvironment, because I have
patches in bug 889714 to remove its state-dependence on the error reporter.
I'll switch it to SystemErrorReporter in that bug.
