Fixed
Status Update
Comments
il...@google.com <il...@google.com>
ap...@google.com <ap...@google.com> #2
Project: platform/frameworks/support
Branch: androidx-main
commit 25369f983e26d758a8a027c84b21f20026637181
Author: Chris Craik <ccraik@google.com>
Date: Mon Jul 12 14:05:36 2021
Update JankCollectionHelper to support S gfxinfo
Fixes: 193260119
Relnote: Fixes FrameTimingMetric to work on Android S beta
Test: ./gradlew bench:integration-tests:macrobenchmark:connectedAndroidTest -P android.testInstrumentationRunnerArguments.class=androidx.benchmark.integration.macrobenchmark.TrivialListScrollBenchmark # On R + S
Still manually cherry-picking changes, as the platform copy of the
file triggers many lint warnings in AndroidX build.
Change-Id: Ib60ccf09fb2fa09f128374140c3657015626dd2c
M benchmark/macro/src/main/java/androidx/benchmark/macro/JankCollectionHelper.java
M benchmark/macro/src/main/java/androidx/benchmark/macro/Metric.kt
https://android-review.googlesource.com/1763870
Branch: androidx-main
commit 25369f983e26d758a8a027c84b21f20026637181
Author: Chris Craik <ccraik@google.com>
Date: Mon Jul 12 14:05:36 2021
Update JankCollectionHelper to support S gfxinfo
Fixes: 193260119
Relnote: Fixes FrameTimingMetric to work on Android S beta
Test: ./gradlew bench:integration-tests:macrobenchmark:connectedAndroidTest -P android.testInstrumentationRunnerArguments.class=androidx.benchmark.integration.macrobenchmark.TrivialListScrollBenchmark # On R + S
Still manually cherry-picking changes, as the platform copy of the
file triggers many lint warnings in AndroidX build.
Change-Id: Ib60ccf09fb2fa09f128374140c3657015626dd2c
M benchmark/macro/src/main/java/androidx/benchmark/macro/JankCollectionHelper.java
M benchmark/macro/src/main/java/androidx/benchmark/macro/Metric.kt
il...@google.com <il...@google.com> #3
We've updated the error message to make it more clear what destination you're currently on - this will help you determine if your call to setGraph()
hasn't happened yet (you have a null current destination) or if you've popped to another destination unexpectedly.
ap...@google.com <ap...@google.com> #4
Project: platform/frameworks/support
Branch: snap-temp-L69500000699825513
commit 6ada6bd039f4a28d2760f4912093abc60ab54d84
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436733
Branch: snap-temp-L69500000699825513
commit 6ada6bd039f4a28d2760f4912093abc60ab54d84
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
ap...@google.com <ap...@google.com> #5
Project: platform/frameworks/support
Branch: snap-temp-L62000000699827533
commit e5780347bfba28e4a500bd964d273c282c12dceb
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436737
Branch: snap-temp-L62000000699827533
commit e5780347bfba28e4a500bd964d273c282c12dceb
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
ap...@google.com <ap...@google.com> #6
Project: platform/frameworks/support
Branch: snap-temp-L46100000699831674
commit 7ab7f8b1967945ba0d506120dbc070ecbfb37c13
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436741
Branch: snap-temp-L46100000699831674
commit 7ab7f8b1967945ba0d506120dbc070ecbfb37c13
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
ap...@google.com <ap...@google.com> #7
Project: platform/frameworks/support
Branch: snap-temp-L91000000699844097
commit 4101ca222554fdfae678ff1e6e47b1a4ab319a56
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436542
Branch: snap-temp-L91000000699844097
commit 4101ca222554fdfae678ff1e6e47b1a4ab319a56
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
ap...@google.com <ap...@google.com> #8
Project: platform/frameworks/support
Branch: snap-temp-L34200000699848945
commit 0da3ed71fa5545646d44fb44219b31e7e5621f8f
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436745
Branch: snap-temp-L34200000699848945
commit 0da3ed71fa5545646d44fb44219b31e7e5621f8f
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
ap...@google.com <ap...@google.com> #9
Project: platform/frameworks/support
Branch: snap-temp-L04700000699849955
commit 12b13608ec1155b5780fe44f5ab07cdc93c5ba90
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436750
Branch: snap-temp-L04700000699849955
commit 12b13608ec1155b5780fe44f5ab07cdc93c5ba90
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
ap...@google.com <ap...@google.com> #10
Project: platform/frameworks/support
Branch: snap-temp-L69500000699869549
commit 7204d04ad74baf9816389e27778266391fbd79a5
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436913
Branch: snap-temp-L69500000699869549
commit 7204d04ad74baf9816389e27778266391fbd79a5
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
ap...@google.com <ap...@google.com> #11
Project: platform/frameworks/support
Branch: snap-temp-L31300000699869852
commit 398a1fe7bb7792589189574aec5f6e77bb749229
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436917
Branch: snap-temp-L31300000699869852
commit 398a1fe7bb7792589189574aec5f6e77bb749229
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
ap...@google.com <ap...@google.com> #12
Project: platform/frameworks/support
Branch: snap-temp-L53700000699921463
commit 31027c16ff20b10e78093f8de205c81fc49dfc92
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436920
Branch: snap-temp-L53700000699921463
commit 31027c16ff20b10e78093f8de205c81fc49dfc92
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
ap...@google.com <ap...@google.com> #13
Project: platform/frameworks/support
Branch: snap-temp-L25200000699921867
commit 63e58ff4f522eb70dec6c0749679fb6b963698d8
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436924
Branch: snap-temp-L25200000699921867
commit 63e58ff4f522eb70dec6c0749679fb6b963698d8
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
ap...@google.com <ap...@google.com> #14
Project: platform/frameworks/support
Branch: snap-temp-L07700000699933785
commit 56fe0d47de20fb430c4280332a20eb96076dd44b
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/1436929
Branch: snap-temp-L07700000699933785
commit 56fe0d47de20fb430c4280332a20eb96076dd44b
Author: Ian Lake <ilake@google.com>
Date: Mon Sep 14 16:10:06 2020
Mention the current destination in getBackStackEntry errors
Improve the debugging experience for "No destination
with ID..." errors in getBackStackEntry() by mentioning
exactly destination the NavController is on. This would
allow developers to know if they have called popBackStack()
to a destination they don't expect to be at or if
they have not called setGraph() at all (where the
current destination would be null).
Test: existing tests pass
BUG: 168311416
Change-Id: Ia96b6732d7caadbddf31b7f35a1a419407ff6e25
(cherry picked from commit d0a10be065a3a629e3835f28d35804c91d8d2e4d)
M navigation/navigation-runtime/src/main/java/androidx/navigation/NavController.java
vi...@gws.hotstar.com <vi...@gws.hotstar.com> #15
getting this error even after ensuring we are setting graph before using it..
Caused by java.lang.IllegalArgumentException
No destination with ID 2131427956 is on the NavController's back stack in HiltNavGraphViewModelLazy.kt:49) , we are using androidx.hilt:hilt-navigation-fragment:1.0.0
androidx.navigation.NavController.getBackStackEntry (NavController.kt:2204)
androidx.hilt.navigation.fragment.HiltNavGraphViewModelLazyKt$hiltNavGraphViewModels$backStackEntry$2.invoke (HiltNavGraphViewModelLazyKt.java:49)
$special$$inlined$hiltNavGraphViewModels$4.invoke (HiltNavGraphViewModelLazy.kt:49)
is there any way to prevent it?
Caused by java.lang.IllegalArgumentException
No destination with ID 2131427956 is on the NavController's back stack in HiltNavGraphViewModelLazy.kt:49) , we are using androidx.hilt:hilt-navigation-fragment:1.0.0
androidx.navigation.NavController.getBackStackEntry (NavController.kt:2204)
androidx.hilt.navigation.fragment.HiltNavGraphViewModelLazyKt$hiltNavGraphViewModels$backStackEntry$2.invoke (HiltNavGraphViewModelLazyKt.java:49)
$special$$inlined$hiltNavGraphViewModels$4.invoke (HiltNavGraphViewModelLazy.kt:49)
is there any way to prevent it?
al...@gmail.com <al...@gmail.com> #16
Could we further improve this by indicating the name of the destination instead of just the ID number?
jb...@google.com <jb...@google.com> #17
If you use a resource to provide the name it will already be displayed. Along with any route or label you may have added.
sh...@gmail.com <sh...@gmail.com> #18
We are also getting this error even after ensuring we are setting the graph before using .popBackStack().
Is there any way to safeguard against this? I am not able to reproduce the error myself, but get a lot of errors show up in Crashlytics
Is there any way to safeguard against this? I am not able to reproduce the error myself, but get a lot of errors show up in Crashlytics
wm...@gmail.com <wm...@gmail.com> #19
I have the same problem
ze...@gmail.com <ze...@gmail.com> #20
Same here. It is not fixed. Can you reopen and look again?
ir...@gmail.com <ir...@gmail.com> #21
Same problem here
ji...@gmail.com <ji...@gmail.com> #22
Same problem here
ru...@gmail.com <ru...@gmail.com> #23
Same problem here
fa...@fob-solutions.com <fa...@fob-solutions.com> #24
Same problem here, currently using version 2.7.7
Description
Version used: 2.3.0
While using `by navGraphViewModels`, my crash reporting reports an error when invoked
NavGraphViewModelLazy.kt line 56
Fatal Exception: java.lang.IllegalArgumentException: No destination with ID 2131296839 is on the NavController's back stack
at androidx.navigation.NavController.getBackStackEntry(NavController.java:1293)
at com.example.ExampleFragment$$special$$inlined$navGraphViewModels$1.invoke(NavGraphViewModelLazy.kt:56)
[...]
This is difficult to debug since the navGraphId that I pass in should theoretically always be in the NavController's back stack when navGraphViewModels is invoked. The error message could be improved by letting me know what IS available on the back stack or if the back stack is completely empty.