Re: [v8-users] API changes upcoming to make writing exception safe code more easy
In C++ you can't overload a method with just a different return type. Since making the context explicit instead of hoping that the right one is entered is nice to have, it was a handy way to change the return type. On Thu, Apr 9, 2015 at 6:25 PM Adam Klein ad...@chromium.org wrote: On Fri, Feb 27, 2015 at 2:43 AM, Michael Hablich habl...@chromium.org wrote: Hey v8-users, we're making big changes to the api (again). We've found that our api makes it extremely difficult to write exception safe code. *Reference issue* https://code.google.com/p/v8/issues/detail?id=3929 *Further description* Consider the following: LocalValue x = some_value; s = x.ToString(); // in the current context, ToString might throw an exception, run out of stack space, whatever... // if that happens we just return an empty LocalString s-Anything() // Crash! There's too much implicit stuff happening here, and it's bad. It's especially bad if you use threads and rely on TerminateExecution(), which causes lots of v8 function to return empty handles unexpectedly. To fix this, we will begin adding functions whose signature makes it impossible to make this mistake and we will deprecate and eventually remove all old functions. The new functions will in general come in two flavours: functions like: LocalString ToString(Isolate*); will become: MaybeLocalString ToString(LocalContext); and functions like: double NumberValue(); will become: Maybebool NumberValue(LocalContext); The Maybe values ensure at compilation time that the value returned is checked by the embedder, and the explicit Context makes it clear that a context is actually required and that javascript may be executed in that context. I'm curious about this bit of the design: why was it decided to add an argument here rather than require a Context to be entered (via Context::Scope)? Rather late to the discussion, I know. Apologies - Adam *Timeline* We will add the new API parts gradually to the codebase. When this is finished there will be approx. 6 weeks of time where the old and the new API will exist side-by-side. This is a good time to make the adjustments in your embedding code. After this period the old API will get removed. We apologize in advance for any trouble this may cause, but we're positive that this change will reduce crash rates for practically all v8 embedders. Cheers, Michael Hablich -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [v8-users] API changes upcoming to make writing exception safe code more easy
Interesting. I agree it's nice to have in a debugging sort of way, both for embedders and v8 itself (no weird crashes due to people forgetting to enter a Context). But I wonder if we're now in a sort of inconsistent state, where some APIs require entering a Context before calling and others take this as an argument. Are we planning to move more of the API towards _always_ passing a Context? On Thu, Apr 9, 2015 at 10:06 AM, Jochen Eisinger joc...@chromium.org wrote: In C++ you can't overload a method with just a different return type. Since making the context explicit instead of hoping that the right one is entered is nice to have, it was a handy way to change the return type. On Thu, Apr 9, 2015 at 6:25 PM Adam Klein ad...@chromium.org wrote: On Fri, Feb 27, 2015 at 2:43 AM, Michael Hablich habl...@chromium.org wrote: Hey v8-users, we're making big changes to the api (again). We've found that our api makes it extremely difficult to write exception safe code. *Reference issue* https://code.google.com/p/v8/issues/detail?id=3929 *Further description* Consider the following: LocalValue x = some_value; s = x.ToString(); // in the current context, ToString might throw an exception, run out of stack space, whatever... // if that happens we just return an empty LocalString s-Anything() // Crash! There's too much implicit stuff happening here, and it's bad. It's especially bad if you use threads and rely on TerminateExecution(), which causes lots of v8 function to return empty handles unexpectedly. To fix this, we will begin adding functions whose signature makes it impossible to make this mistake and we will deprecate and eventually remove all old functions. The new functions will in general come in two flavours: functions like: LocalString ToString(Isolate*); will become: MaybeLocalString ToString(LocalContext); and functions like: double NumberValue(); will become: Maybebool NumberValue(LocalContext); The Maybe values ensure at compilation time that the value returned is checked by the embedder, and the explicit Context makes it clear that a context is actually required and that javascript may be executed in that context. I'm curious about this bit of the design: why was it decided to add an argument here rather than require a Context to be entered (via Context::Scope)? Rather late to the discussion, I know. Apologies - Adam *Timeline* We will add the new API parts gradually to the codebase. When this is finished there will be approx. 6 weeks of time where the old and the new API will exist side-by-side. This is a good time to make the adjustments in your embedding code. After this period the old API will get removed. We apologize in advance for any trouble this may cause, but we're positive that this change will reduce crash rates for practically all v8 embedders. Cheers, Michael Hablich -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [v8-users] API changes upcoming to make writing exception safe code more easy
I've already converted most of the functions to take a context that might use one internally. Part of the change is to make explicit what v8 maybe should never have made implicit. I've found a number of places when calls are made that require a context internally on some uncommon paths but we're using them without one. On Thursday, April 9, 2015 at 7:36:43 PM UTC+2, Adam Klein wrote: Interesting. I agree it's nice to have in a debugging sort of way, both for embedders and v8 itself (no weird crashes due to people forgetting to enter a Context). But I wonder if we're now in a sort of inconsistent state, where some APIs require entering a Context before calling and others take this as an argument. Are we planning to move more of the API towards _always_ passing a Context? On Thu, Apr 9, 2015 at 10:06 AM, Jochen Eisinger joc...@chromium.org javascript: wrote: In C++ you can't overload a method with just a different return type. Since making the context explicit instead of hoping that the right one is entered is nice to have, it was a handy way to change the return type. On Thu, Apr 9, 2015 at 6:25 PM Adam Klein ad...@chromium.org javascript: wrote: On Fri, Feb 27, 2015 at 2:43 AM, Michael Hablich hab...@chromium.org javascript: wrote: Hey v8-users, we're making big changes to the api (again). We've found that our api makes it extremely difficult to write exception safe code. *Reference issue* https://code.google.com/p/v8/issues/detail?id=3929 *Further description* Consider the following: LocalValue x = some_value; s = x.ToString(); // in the current context, ToString might throw an exception, run out of stack space, whatever... // if that happens we just return an empty LocalString s-Anything() // Crash! There's too much implicit stuff happening here, and it's bad. It's especially bad if you use threads and rely on TerminateExecution(), which causes lots of v8 function to return empty handles unexpectedly. To fix this, we will begin adding functions whose signature makes it impossible to make this mistake and we will deprecate and eventually remove all old functions. The new functions will in general come in two flavours: functions like: LocalString ToString(Isolate*); will become: MaybeLocalString ToString(LocalContext); and functions like: double NumberValue(); will become: Maybebool NumberValue(LocalContext); The Maybe values ensure at compilation time that the value returned is checked by the embedder, and the explicit Context makes it clear that a context is actually required and that javascript may be executed in that context. I'm curious about this bit of the design: why was it decided to add an argument here rather than require a Context to be entered (via Context::Scope)? Rather late to the discussion, I know. Apologies - Adam *Timeline* We will add the new API parts gradually to the codebase. When this is finished there will be approx. 6 weeks of time where the old and the new API will exist side-by-side. This is a good time to make the adjustments in your embedding code. After this period the old API will get removed. We apologize in advance for any trouble this may cause, but we're positive that this change will reduce crash rates for practically all v8 embedders. Cheers, Michael Hablich -- -- v8-users mailing list v8-u...@googlegroups.com javascript: http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+u...@googlegroups.com javascript:. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-u...@googlegroups.com javascript: http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+u...@googlegroups.com javascript:. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-u...@googlegroups.com javascript: http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+u...@googlegroups.com javascript:. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [v8-users] API changes upcoming to make writing exception safe code more easy
Excellent to hear, this sounds like an overall win (I say this as someone who in my early V8 interactions often found myself surprised by the need of a Context in cases I'd have guessed didn't need one). On Thu, Apr 9, 2015 at 10:44 AM, Dan Carney dcar...@chromium.org wrote: I've already converted most of the functions to take a context that might use one internally. Part of the change is to make explicit what v8 maybe should never have made implicit. I've found a number of places when calls are made that require a context internally on some uncommon paths but we're using them without one. On Thursday, April 9, 2015 at 7:36:43 PM UTC+2, Adam Klein wrote: Interesting. I agree it's nice to have in a debugging sort of way, both for embedders and v8 itself (no weird crashes due to people forgetting to enter a Context). But I wonder if we're now in a sort of inconsistent state, where some APIs require entering a Context before calling and others take this as an argument. Are we planning to move more of the API towards _always_ passing a Context? On Thu, Apr 9, 2015 at 10:06 AM, Jochen Eisinger joc...@chromium.org wrote: In C++ you can't overload a method with just a different return type. Since making the context explicit instead of hoping that the right one is entered is nice to have, it was a handy way to change the return type. On Thu, Apr 9, 2015 at 6:25 PM Adam Klein ad...@chromium.org wrote: On Fri, Feb 27, 2015 at 2:43 AM, Michael Hablich hab...@chromium.org wrote: Hey v8-users, we're making big changes to the api (again). We've found that our api makes it extremely difficult to write exception safe code. *Reference issue* https://code.google.com/p/v8/issues/detail?id=3929 *Further description* Consider the following: LocalValue x = some_value; s = x.ToString(); // in the current context, ToString might throw an exception, run out of stack space, whatever... // if that happens we just return an empty LocalString s-Anything() // Crash! There's too much implicit stuff happening here, and it's bad. It's especially bad if you use threads and rely on TerminateExecution(), which causes lots of v8 function to return empty handles unexpectedly. To fix this, we will begin adding functions whose signature makes it impossible to make this mistake and we will deprecate and eventually remove all old functions. The new functions will in general come in two flavours: functions like: LocalString ToString(Isolate*); will become: MaybeLocalString ToString(LocalContext); and functions like: double NumberValue(); will become: Maybebool NumberValue(LocalContext); The Maybe values ensure at compilation time that the value returned is checked by the embedder, and the explicit Context makes it clear that a context is actually required and that javascript may be executed in that context. I'm curious about this bit of the design: why was it decided to add an argument here rather than require a Context to be entered (via Context::Scope)? Rather late to the discussion, I know. Apologies - Adam *Timeline* We will add the new API parts gradually to the codebase. When this is finished there will be approx. 6 weeks of time where the old and the new API will exist side-by-side. This is a good time to make the adjustments in your embedding code. After this period the old API will get removed. We apologize in advance for any trouble this may cause, but we're positive that this change will reduce crash rates for practically all v8 embedders. Cheers, Michael Hablich -- -- v8-users mailing list v8-u...@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+u...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-u...@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+u...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-u...@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+u...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it,
Re: [v8-users] API changes upcoming to make writing exception safe code more easy
On Fri, Feb 27, 2015 at 2:43 AM, Michael Hablich habl...@chromium.org wrote: Hey v8-users, we're making big changes to the api (again). We've found that our api makes it extremely difficult to write exception safe code. *Reference issue* https://code.google.com/p/v8/issues/detail?id=3929 *Further description* Consider the following: LocalValue x = some_value; s = x.ToString(); // in the current context, ToString might throw an exception, run out of stack space, whatever... // if that happens we just return an empty LocalString s-Anything() // Crash! There's too much implicit stuff happening here, and it's bad. It's especially bad if you use threads and rely on TerminateExecution(), which causes lots of v8 function to return empty handles unexpectedly. To fix this, we will begin adding functions whose signature makes it impossible to make this mistake and we will deprecate and eventually remove all old functions. The new functions will in general come in two flavours: functions like: LocalString ToString(Isolate*); will become: MaybeLocalString ToString(LocalContext); and functions like: double NumberValue(); will become: Maybebool NumberValue(LocalContext); The Maybe values ensure at compilation time that the value returned is checked by the embedder, and the explicit Context makes it clear that a context is actually required and that javascript may be executed in that context. I'm curious about this bit of the design: why was it decided to add an argument here rather than require a Context to be entered (via Context::Scope)? Rather late to the discussion, I know. Apologies - Adam *Timeline* We will add the new API parts gradually to the codebase. When this is finished there will be approx. 6 weeks of time where the old and the new API will exist side-by-side. This is a good time to make the adjustments in your embedding code. After this period the old API will get removed. We apologize in advance for any trouble this may cause, but we're positive that this change will reduce crash rates for practically all v8 embedders. Cheers, Michael Hablich -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[v8-users] API changes upcoming to make writing exception safe code more easy
Hey v8-users, we're making big changes to the api (again). We've found that our api makes it extremely difficult to write exception safe code. *Reference issue* https://code.google.com/p/v8/issues/detail?id=3929 *Further description* Consider the following: LocalValue x = some_value; s = x.ToString(); // in the current context, ToString might throw an exception, run out of stack space, whatever... // if that happens we just return an empty LocalString s-Anything() // Crash! There's too much implicit stuff happening here, and it's bad. It's especially bad if you use threads and rely on TerminateExecution(), which causes lots of v8 function to return empty handles unexpectedly. To fix this, we will begin adding functions whose signature makes it impossible to make this mistake and we will deprecate and eventually remove all old functions. The new functions will in general come in two flavours: functions like: LocalString ToString(Isolate*); will become: MaybeLocalString ToString(LocalContext); and functions like: double NumberValue(); will become: Maybebool NumberValue(LocalContext); The Maybe values ensure at compilation time that the value returned is checked by the embedder, and the explicit Context makes it clear that a context is actually required and that javascript may be executed in that context. *Timeline* We will add the new API parts gradually to the codebase. When this is finished there will be approx. 6 weeks of time where the old and the new API will exist side-by-side. This is a good time to make the adjustments in your embedding code. After this period the old API will get removed. We apologize in advance for any trouble this may cause, but we're positive that this change will reduce crash rates for practically all v8 embedders. Cheers, Michael Hablich -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups v8-users group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
