feat: show info on what would be deleted (#6235)

This PR updates the way we show deleted strategies in the CR UI. Instead
of showing just the strategy name and a diff on hover, we show the same
strategy config as we do for new and updated strategies.

This makes it easier to see what you have deleted.

In doing so, it also fixes two issues:
1. inconsistent border radius for segment changes listed. Due to an
override in `frontend/src/themes/theme.ts`, these would get a border
radius of `theme.shape.borderRadiusLarge` instead of
`theme.shape.borderRadiusMedium`. It does this by adding a class and
making the selector more specific.
2. The background was unset for the strategy rollout box and constraint
item boxes.

It looks like this:

<img width="728" alt="image"
src="https://github.com/Unleash/unleash/assets/17786332/7cba28ac-0454-444d-8cfa-f46543ccf2dc">

<img width="728" alt="image"
src="https://github.com/Unleash/unleash/assets/17786332/832be653-3def-4afc-b72f-36fcd76ad83d">

Or with more kinds of strategies:
<img width="454" alt="image"
src="https://github.com/Unleash/unleash/assets/17786332/f18e5482-7d2e-4cbd-8177-9de6dfb10307">


Note: I'm happy to isolate the color changes to a separate PR if that's
preferable.

frontend/src/component/changeRequest/ChangeRequest/Changes/Change/FeatureChange.tsx

@@ -66,6 +66,13 @@ const InlineList = styled('ul')(({ theme }) => ({
     },
 }));
 
+const ChangeInnerBox = styled(Box)(({ theme }) => ({
+    padding: theme.spacing(3),
+    '&:has(.delete-strategy-information-wrapper)': {
+        backgroundColor: theme.palette.error.light,
+    },
+}));
+
 export const FeatureChange: FC<{
     actions: ReactNode;
     index: number;
@@ -134,7 +141,7 @@ export const FeatureChange: FC<{
                 }
             />
 
-            <Box sx={(theme) => ({ padding: theme.spacing(3) })}>
+            <ChangeInnerBox>
                 {(change.action === 'addDependency' ||
                     change.action === 'deleteDependency') && (
                     <DependencyChange
@@ -183,7 +190,7 @@ export const FeatureChange: FC<{
                         actions={actions}
                     />
                 )}
-            </Box>
+            </ChangeInnerBox>
         </StyledSingleChangeBox>
     );
 };

frontend/src/component/changeRequest/ChangeRequest/Changes/Change/StrategyChange.tsx

@@ -25,7 +25,7 @@ export const ChangeItemWrapper = styled(Box)({
     alignItems: 'center',
 });
 
-const ChangeItemCreateEditWrapper = styled(Box)(({ theme }) => ({
+const ChangeItemCreateEditDeleteWrapper = styled(Box)(({ theme }) => ({
     display: 'grid',
     gridTemplateColumns: 'auto auto',
     justifyContent: 'space-between',
@@ -142,7 +142,7 @@ export const StrategyChange: VFC<{
         <>
             {change.action === 'addStrategy' && (
                 <>
-                    <ChangeItemCreateEditWrapper>
+                    <ChangeItemCreateEditDeleteWrapper>
                         <ChangeItemInfo>
                             <Typography
                                 color={
@@ -167,7 +167,7 @@ export const StrategyChange: VFC<{
                             </div>
                         </ChangeItemInfo>
                         <div>{actions}</div>
-                    </ChangeItemCreateEditWrapper>
+                    </ChangeItemCreateEditDeleteWrapper>
                     <StrategyExecution strategy={change.payload} />
                     <ConditionallyRender
                         condition={hasVariantDiff}
@@ -187,7 +187,8 @@ export const StrategyChange: VFC<{
                 </>
             )}
             {change.action === 'deleteStrategy' && (
-                <ChangeItemWrapper>
+                <>
+                    <ChangeItemCreateEditDeleteWrapper className='delete-strategy-information-wrapper'>
                         <ChangeItemInfo>
                             <Typography
                                 sx={(theme) => ({
@@ -206,7 +207,20 @@ export const StrategyChange: VFC<{
                             )}
                         </ChangeItemInfo>
                         <div>{actions}</div>
-                </ChangeItemWrapper>
+                    </ChangeItemCreateEditDeleteWrapper>
+                    <ConditionallyRender
+                        condition={Boolean(currentStrategy)}
+                        show={
+                            <Typography>
+                                {
+                                    <StrategyExecution
+                                        strategy={currentStrategy!}
+                                    />
+                                }
+                            </Typography>
+                        }
+                    />
+                </>
             )}
             {change.action === 'updateStrategy' && (
                 <>
@@ -214,7 +228,7 @@ export const StrategyChange: VFC<{
                         currentStrategy={currentStrategy}
                         change={change}
                     />
-                    <ChangeItemCreateEditWrapper>
+                    <ChangeItemCreateEditDeleteWrapper>
                         <ChangeItemInfo>
                             <EditHeader
                                 wasDisabled={currentStrategy?.disabled}
@@ -231,7 +245,7 @@ export const StrategyChange: VFC<{
                             </StrategyTooltipLink>
                         </ChangeItemInfo>
                         <div>{actions}</div>
-                    </ChangeItemCreateEditWrapper>
+                    </ChangeItemCreateEditDeleteWrapper>
                     <ConditionallyRender
                         condition={
                             change.payload?.disabled !==

frontend/src/component/common/ConstraintAccordion/ConstraintAccordionList/ConstraintAccordionList.tsx

@@ -39,11 +39,15 @@ interface IConstraintAccordionListItemState {
 
 export const constraintAccordionListId = 'constraintAccordionListId';
 
-const StyledContainer = styled('div')({
+const StyledContainer = styled('div')(({ theme }) => ({
     width: '100%',
     display: 'flex',
     flexDirection: 'column',
-});
+    '&.constraint-list-element': {
+        borderRadius: theme.shape.borderRadiusMedium,
+        backgroundColor: theme.palette.background.default,
+    },
+}));
 
 const StyledHelpWrapper = styled(Tooltip)(({ theme }) => ({
     marginLeft: theme.spacing(0.75),
@@ -224,7 +228,10 @@ export const ConstraintList = forwardRef<
     }
 
     return (
-        <StyledContainer id={constraintAccordionListId}>
+        <StyledContainer
+            id={constraintAccordionListId}
+            className='constraint-list-element'
+        >
             {constraints.map((constraint, index) => (
                 <Fragment key={objectId(constraint)}>
                     <ConditionallyRender

frontend/src/component/common/SegmentItem/SegmentItem.tsx

@@ -25,7 +25,9 @@ const StyledAccordion = styled(Accordion, {
     shouldForwardProp: (prop) => prop !== 'isDisabled',
 })<{ isDisabled: boolean | null }>(({ theme, isDisabled }) => ({
     border: `1px solid ${theme.palette.divider}`,
+    '&.segment-accordion': {
         borderRadius: theme.shape.borderRadiusMedium,
+    },
     boxShadow: 'none',
     margin: 0,
     transition: 'all 0.1s ease',
@@ -70,7 +72,7 @@ export const SegmentItem: VFC<ISegmentItemProps> = ({
     const [isOpen, setIsOpen] = useState(isExpanded || false);
 
     return (
-        <StyledAccordion isDisabled={disabled}>
+        <StyledAccordion className='segment-accordion' isDisabled={disabled}>
             <StyledAccordionSummary id={`segment-accordion-${segment.id}`}>
                 <DonutLarge
                     sx={(theme) => ({

frontend/src/component/feature/FeatureView/FeatureOverview/FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/StrategyDraggableItem/StrategyItem/StrategyExecution/ConstraintItem/ConstraintItem.tsx

@@ -11,6 +11,7 @@ const StyledContainer = styled('div')(({ theme }) => ({
     width: '100%',
     padding: theme.spacing(2, 3),
     borderRadius: theme.shape.borderRadiusMedium,
+    background: theme.palette.background.default,
     border: `1px solid ${theme.palette.divider}`,
 }));
 

frontend/src/component/feature/FeatureView/FeatureOverview/FeatureOverviewEnvironments/FeatureOverviewEnvironment/EnvironmentAccordionBody/StrategyDraggableItem/StrategyItem/StrategyExecution/StrategyExecution.tsx

@@ -51,6 +51,7 @@ const StyledValueContainer = styled(Box)(({ theme }) => ({
     padding: theme.spacing(2, 3),
     border: `1px solid ${theme.palette.divider}`,
     borderRadius: theme.shape.borderRadiusMedium,
+    background: theme.palette.background.default,
 }));
 
 const StyledValueSeparator = styled('span')(({ theme }) => ({