<AWT Dev> [13] JDK-8218917: KeyEvent.getModifiers() returns inconsistent values for ALT keys
Krishna Addepalli
krishna.addepalli at oracle.com
Wed Apr 10 14:51:50 UTC 2019
Hi Sergey Bylokhov/Phil/Prasanta/Jay,
Could you review the fix for this issue? Here is the webrev: http://cr.openjdk.java.net/~kaddepalli/8218917/webrev00/ <http://cr.openjdk.java.net/~kaddepalli/8218917/webrev00/>
@Sergey Malenkov, I have raised a new bug JDK-8222279: https://bugs.openjdk.java.net/browse/JDK-8222279 <https://bugs.openjdk.java.net/browse/JDK-8222279>, under which we can further discuss your concerns, and accordingly take a decision and implement accordingly.
For now, I think my fix which just addresses the issue at hand should be pushed, to avoid inconvenience.
Thanks,
Krishna
> On 08-Apr-2019, at 10:33 AM, Krishna Addepalli <krishna.addepalli at oracle.com> wrote:
>
> Hi Sergey Malenkov,
>
> Any chance that you can agree on my proposal?
> If you are okay I can raise a new bug for addressing your concern, and fixing the current problem at hand?
>
> Thanks,
> Krishna
>
>> On 26-Mar-2019, at 4:26 PM, Krishna Addepalli <krishna.addepalli at oracle.com> wrote:
>>
>> Hi Sergey Malenkov,
>>
>> My fix exactly solves the problem of right alt hijacking the state and always sending a ALTGR key even if left ALT only was pressed.
>>
>> What I meant by same behaviour is that pressing the left ALT and then pressing the ALTGR key(or vice versa) will deliver the event with KeyPressed 0.
>> Even my proposed fix restores this behaviour. Whether this is a correct behaviour is a different matter.
>> I still maintain that, we should fix the immediate problem at hand (since that is minimal code changes), and then continue the discussion of how to support the ALTGR behaviour under a different bug(it could as well become an enhancement).
>>
>> Thanks,
>> Krishna
>>
>>> On 21-Mar-2019, at 4:04 PM, Sergey Malenkov <malenkov at gmail.com> wrote:
>>>
>>> Hi Krishna,
>>>
>>>> But, currently, with my fix, the code will behave exactly as in Java 1.8.
>>>
>>> Nope, it still sends VK_ALT_GRAPH pressed event for the right Alt.
>>>
>>> http://bugs.openjdk.java.net/browse/JDK-8151136
>>> According to the issue above AltGr support was backported to 9.
>>>
>>>
>>> On Wed, Mar 20, 2019 at 2:18 PM Krishna Addepalli
>>> <krishna.addepalli at oracle.com> wrote:
>>>>
>>>> Hi Sergey Malenkov,
>>>>
>>>> We can debate on how to treat the ALTGR_KEY, and can choose to include the behaviour as a system flag.
>>>> But, currently, with my fix, the code will behave exactly as in Java 1.8. Even there, when I pressed ALTGR key, after holding ALT key, I observed a KeyEvent 0 being sent.
>>>>
>>>> I would suggest to re-look at my fix which fixes the current problem at hand, and perhaps we can move this discussion under a new bug.
>>>>
>>>> Thanks,
>>>> Krishna
>>>>
>>>> On 18-Mar-2019, at 8:02 PM, Sergey Malenkov <malenkov at gmail.com> wrote:
>>>>
>>>> Hi Sergey,
>>>>
>>>> ALT_GRAPH_DOWN_MASK is not the only mask missing in JavaDoc. What is
>>>> about META_DOWN_MASK? What if the developer, who does not care about
>>>> ALT_GRAPH, forget about META too? Guess how your example will work on
>>>> Mac. What is about the WORA slogan?
>>>>
>>>> I believe that the example in the javadoc is not entirely correct.
>>>> This is just a very simple example, related to the English locale on
>>>> Windows (and possibly on Linux). It should not be used in
>>>> multi-platform code.
>>>>
>>>>
>>>>
>>>> On Sun, Mar 17, 2019 at 1:26 AM Sergey Bylokhov
>>>> <Sergey.Bylokhov at oracle.com> wrote:
>>>>
>>>>
>>>> On 16/03/2019 03:58, Sergey Malenkov wrote:
>>>>
>>>> Your example is synthetic and shows a problem in the one specific
>>>> case. I think if you introduce new mask, you have to use it in your
>>>> example too. If you add ALT_GRAPH_DOWN_MASK to 'offmask' your example
>>>> will not work (that's how processed all shortcuts in Swing and IDEA).
>>>> If you add it to 'onmask' the KeyEvent(new Button(), 0, 0,
>>>> ALT_GRAPH_DOWN_MASK, 0) will not work.
>>>>
>>>>
>>>> Your example is good as well, but it shows the opposite, if
>>>> ALT_GRAPH_DOWN_MASK was used as "onmask" or as "offmask" then it means
>>>> that this example tries to take care about altGr and it only
>>>> properly works after the fix. And if the code is unaware about the altGr
>>>> flag as in previous example it will be ignored.
>>>>
>>>> Am I right that to support your specific case you have to find and fix
>>>> all Alt-based shortcuts in Swing, we should fix all Alt-based
>>>> shortcuts in all keymaps in our IDEs and we should notify all our
>>>> users that they have to fix all Alt-based shortcuts in their custom
>>>> keymaps? The brilliant example of backward compatibility!
>>>>
>>>>
>>>> I do not remember all changes which were integrated since initially it was done
>>>> ~4 years ago. But Swing was updated by some changes after that, for example:
>>>> https://bugs.openjdk.java.net/browse/JDK-8194873
>>>>
>>>>
>>>> So if the client will follow the spec below it should work as before, isn't it?:
>>>> https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/java/awt/event/InputEvent.html#getModifiersEx()
>>>>
>>>>
>>>> If a developer use this method as described his code will be broken
>>>> too, because good and attentive developer definitely added
>>>> ALT_GRAPH_DOWN_MASK to 'offmask'.
>>>>
>>>>
>>>> If the user wants to ignore all combinations with "Alternate Character Key"
>>>> then, as you pointed in the start of this thread, he should ignore both
>>>> "alt" since on macOS both alt keys are "Alternate Character Key".
>>>>
>>>>
>>>> On Sat, Mar 16, 2019 at 1:27 AM Sergey Bylokhov
>>>> <Sergey.Bylokhov at oracle.com> wrote:
>>>>
>>>>
>>>> On 15/03/2019 05:54, Sergey Malenkov wrote:
>>>>
>>>> We have a major issue about unexpected AltGr in the keyboard layout
>>>> that should not have AltGr at all:
>>>> https://urldefense.proofpoint.com/v2/url?u=http-3A__youtrack.jetbrains.com_issue_IDEA-2D206348&d=DwIFaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=QF7AertWDY_M4hfHg_4S-iyX-aP0wtLYwZFgs0zfX_k&m=j-gQEy4UDmzd3Sa5zjEYskUw4CoYUZ9gDurLkGu1YOo&s=HcCKCq8FPyOoJEvT4qk59DJqCAiRB-BvECy_VCAdpqI&e=
>>>> Why you decided to support AltGr for every keyboard layout? It really
>>>> breaks backward compatibility!
>>>>
>>>>
>>>> Even in your bug report the people complain that altGr key does not work, and
>>>> the only problem here is that it does not assigned by default.
>>>> But on the other side it is possible to set separate shortcuts
>>>> to the "Alt + Alt Graph + Enter"and "Alt + Enter":
>>>>
>>>> I think the main client is Swing and pressed AltGr that looks like
>>>> 'Alt+AltGr+' breaks all Alt-based shortcuts defined in
>>>> javax.swing.plaf.basic.BasicLookAndFeel#initComponentDefaults and
>>>> other places. Now, if you press "alt LEFT", the "moveColumnLeft"
>>>> action is performed only for the left Alt. And this also breaks a
>>>> backward compatibility.
>>>>
>>>>
>>>> The term "all" is not so critical, there are only few such shortcuts, and it is
>>>> a good thing that potentially we can set different shortcuts for each.
>>>> This is a bug that these places were not updated, it is easy to fix since this
>>>> is not exposed via public API.
>>>> But we will get the same result if we will use the AltGr mask only.
>>>>
>>>> It is not backward compatible to use AltGr instead of right Alt in
>>>> both cases. Instead of 'Alt+key' you will get 'AltGr+key' or
>>>> 'Alt+AltGr+key', which are not bound to any action.
>>>>
>>>>
>>>> It is compatible to the specification of InputEvent.getModifiersEx():
>>>> KeyEvent event = new KeyEvent(new Button(), 0, 0,
>>>> ALT_DOWN_MASK | ALT_GRAPH_DOWN_MASK, 0);
>>>> int onmask = ALT_DOWN_MASK;
>>>> int offmask = CTRL_DOWN_MASK|SHIFT_DOWN_MASK;
>>>> if ((event.getModifiersEx() & (onmask | offmask)) == onmask) {
>>>> ...
>>>> }
>>>>
>>>> The code above works before and after the change for altGr.
>>>> But it will stop working if we will use altGr only, and it will be hard to argue
>>>> why the ALT flag is not set while alt key is pressed(since on some keyboards this key is
>>>> marked as alt and on some other altGr).
>>>>
>>>> And as specially noted in the method above the code should not assume which
>>>> flags(and how many) were set by the actions, if such assumptions exists in
>>>> Swing itself they should be fixed as well.
>>>>
>>>>
>>>> On Fri, Mar 15, 2019 at 9:27 AM Krishna Addepalli
>>>> <krishna.addepalli at oracle.com> wrote:
>>>>
>>>>
>>>> Hi Sergey Malenkov,
>>>>
>>>> 'Alt+AltGr+Right' does nothing, because we do not assign this shortcut yet
>>>>
>>>> In my personal experience, I did not find any instance, wherein a shortcut had left and right alt in it.
>>>> Although it is not impossible, it seems weird to define such shortcuts.
>>>> It would be helpful if you could point to some resources, wherein defining such shortcuts is acceptable.
>>>>
>>>> Thanks,
>>>> Krishna
>>>>
>>>> On 14-Mar-2019, at 4:03 PM, Sergey Malenkov <malenkov at gmail.com> wrote:
>>>>
>>>> I strongly don't like two masks for one key. If you press VK_ALT,
>>>> ALT_DOWN_MASK should be set. If you press VK_SHIFT then,
>>>> SHIFT_DOWN_MASK should be added to indicate that both keys are
>>>> pressed. And if you press VK_ALT_GRAPH, only ALT_GRAPH_DOWN_MASK
>>>> should be added. Otherwise, you can't distinguish the following key
>>>> strokes: 'AltGr+Right' and 'Alt+AltGr+Right'. But these keystrokes are
>>>> different and should invoke different actions. For example,
>>>> 'Alt+Right' moves cursor to the next word
>>>> 'Alt+Shift+Right' moves cursor to the next word AND adds all skipped
>>>> characters to selection
>>>> 'Alt+AltGr+Right' does nothing, because we do not assign this shortcut yet
>>>>
>>>> On Thu, Mar 14, 2019 at 12:09 AM Sergey Bylokhov
>>>> <Sergey.Bylokhov at oracle.com> wrote:
>>>>
>>>>
>>>> On 13/03/2019 03:59, Sergey Malenkov wrote:
>>>>
>>>> I missed the "for ALT keys" in the bug title and thought that
>>>> "KeyEvent.getModifiers() returns inconsistent values" was about
>>>> incompatible behaviour on different platforms. In fact, JDK-8218917
>>>> should be renamed to something like “The right Alt key on Mac should
>>>> behave as Alt and must not break the left Alt key processing”.
>>>>
>>>>
>>>> But the "right Alt" should behave like a "left alt" already, it should use both flags:
>>>> the common alt(ALT_DOWN_MASK) and the altGr(ALT_GRAPH_DOWN_MASK).
>>>>
>>>> So if the client will follow the spec below it should work as before, isn't it?:
>>>> https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/java/awt/event/InputEvent.html#getModifiersEx()
>>>>
>>>> On Wed, Mar 13, 2019 at 6:57 AM Sergey Bylokhov
>>>> <Sergey.Bylokhov at oracle.com> wrote:
>>>>
>>>>
>>>> On 12/03/2019 12:28, Sergey Malenkov wrote:
>>>>
>>>> Hi Sergey,
>>>>
>>>> 1. macOS uses a regular Alt key as "Alternate Character Key". This is
>>>> the reason why JDK Toolkit defines Ctrl+Alt to select a mnemonic,
>>>> instead of simple Alt. See
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__sites.google.com_site_malenkov_java_141229&d=DwIFaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=QF7AertWDY_M4hfHg_4S-iyX-aP0wtLYwZFgs0zfX_k&m=j-gQEy4UDmzd3Sa5zjEYskUw4CoYUZ9gDurLkGu1YOo&s=Y6PcJ4DGp2cSnTLEvtsIdt55_u0F8VqL5LSA7vBPbkw&e=
>>>>
>>>>
>>>> Right, but introducing this flag for the "left alt" could cause even more
>>>> issues, so this flag is set only for the right.
>>>>
>>>> 3. Regression was caused by adding AltGr to key processing on Mac. But
>>>> I found more issues with inconsistent key processing on different
>>>> platforms. See https://urldefense.proofpoint.com/v2/url?u=http-3A__sites.google.com_site_malenkov_java_190312&d=DwIFaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=QF7AertWDY_M4hfHg_4S-iyX-aP0wtLYwZFgs0zfX_k&m=j-gQEy4UDmzd3Sa5zjEYskUw4CoYUZ9gDurLkGu1YOo&s=Y7GZdeTQvRyIBxAsCDtaB8PZo9_GRVYIZZvn2VfCzJc&e=
>>>>
>>>>
>>>> Not sure that CAPS_LOCK is related.
>>>>
>>>>
>>>>
>>>> On Tue, Mar 12, 2019 at 4:17 AM Sergey Bylokhov
>>>> <Sergey.Bylokhov at oracle.com> wrote:
>>>>
>>>>
>>>> On 11/03/2019 17:37, Philip Race wrote:
>>>>
>>>> The debate is about AltGraph which an ancient MS-DOSism for
>>>> asking for an ALTernate GRAPHics bitmap font - all pre-dates windows
>>>> and I am sure has never been applicable to any MacOS.
>>>>
>>>>
>>>> It also about the "right alt" which is also know as "AltGraph". I guess currently
>>>> it is implemented as "right alt" on Linux/macOS/windows.
>>>>
>>>> BTW on linux it is also named as "Alternative Characters Key":
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__help.ubuntu.com_community_ComposeKey&d=DwIFaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=QF7AertWDY_M4hfHg_4S-iyX-aP0wtLYwZFgs0zfX_k&m=j-gQEy4UDmzd3Sa5zjEYskUw4CoYUZ9gDurLkGu1YOo&s=DvJtvBcerkulT3S417Vu6hQyXy7e0bI1bX9fInefV-A&e=
>>>>
>>>> So someone needs to properly explain why we would claim a Mac keyboard
>>>> is OK to generate a keycode it doesn't have and cause a slew of regressions
>>>> in the process ...>
>>>> If Mac doesn't distinguish these two, we should generate the same keycode for both.
>>>>
>>>>
>>>> The macOS supports "right alt", otherwise it would not be possible to implement it in java:
>>>> https://urldefense.proofpoint.com/v2/url?u=https-3A__developer.apple.com_library_archive_technotes_tn2450_-5Findex.html&d=DwIFaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=QF7AertWDY_M4hfHg_4S-iyX-aP0wtLYwZFgs0zfX_k&m=j-gQEy4UDmzd3Sa5zjEYskUw4CoYUZ9gDurLkGu1YOo&s=hD5wMxSuL3iN_tqTn0Cd5ULhp_bGzQl3fFnQQdNXNuU&e=
>>>>
>>>>
>>>> One could suppose there is a difference else why two keys, but what is the right
>>>> thing to do here that fixes all the problems. What exactly WAS the problem
>>>> with what was there in the first place ? And if changing it is correct why is it
>>>> causing regressions ?
>>>>
>>>>
>>>> Regressions were caused by the bugs in the fix implementation, or am I missed something?
>>>>
>>>>
>>>>
>>>> -phil.
>>>>
>>>>
>>>>
>>>> On 3/12/19, 5:34 AM, Sergey Bylokhov wrote:
>>>>
>>>> Hi, Phil.
>>>> On 11/03/2019 07:43, Philip Race wrote:
>>>>
>>>> The reasoning that AltGraph might be useful to someone is a bit weak
>>>> and I don't think I'd want to support it via system property or build options.
>>>>
>>>> If its not a platform keyboard key, why do we need it ?
>>>>
>>>>
>>>> The "AltGraph" key is also commonly referred to as "Right Alt", and
>>>> it has been implemented on all platforms as a "Right Alt", it is convenient to
>>>> distinguish the left/right alts.
>>>>
>>>>
>>>>
>>>> --
>>>> Best regards, Sergey.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Best regards, Sergey.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Best regards, Sergey.
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Best regards,
>>>> Sergey A. Malenkov
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Best regards, Sergey.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Best regards, Sergey.
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Best regards,
>>>> Sergey A. Malenkov
>>>>
>>>>
>>>
>>>
>>> --
>>> Best regards,
>>> Sergey A. Malenkov
>>
>
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