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Add git-style diff view for CloudFormation change sets #172

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Merged
kddejong merged 2 commits into from
Jan 30, 2026
Merged

Add git-style diff view for CloudFormation change sets #172

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fdbbf0c
Add git-style diff view for CloudFormation change sets
kddejong Jan 30, 2026
dd81cb9
Remove obsolete tests from rebase
kddejong Jan 30, 2026
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225 changes: 104 additions & 121 deletions __tests__/changeset-formatter.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -426,6 +426,16 @@ describe('Change Set Formatter', () => {
ResourceType: 'AWS::DynamoDB::Table',
Replacement: 'True',
Scope: ['Properties'],
BeforeContext: JSON.stringify({
Properties: {
BillingMode: 'PROVISIONED'
}
}),
AfterContext: JSON.stringify({
Properties: {
BillingMode: 'PAY_PER_REQUEST'
}
}),
Details: [
{
Target: {
Expand Down Expand Up @@ -458,164 +468,135 @@ describe('Change Set Formatter', () => {
)
expect(markdown).toContain('**Physical ID:** `my-table-123`')
expect(markdown).toContain('⚠️ **This resource will be replaced**')
expect(markdown).toContain(
'**BillingMode:** `PROVISIONED` → `PAY_PER_REQUEST`'
)
expect(markdown).toContain('```diff')
expect(markdown).toContain('⚠️ Requires recreation: Always')
})

test('diffs Tags arrays correctly', () => {
test('displays AfterContext for Add actions in console output', () => {
const changesSummary = JSON.stringify({
changes: [
{
Type: 'Resource',
ResourceChange: {
Action: 'Modify',
LogicalResourceId: 'MyParameter',
ResourceType: 'AWS::SSM::Parameter',
Replacement: 'False',
Scope: ['Properties'],
Details: [
{
Target: {
Attribute: 'Properties',
Name: 'Tags',
RequiresRecreation: 'Never',
BeforeValue: JSON.stringify([
{ Key: 'Version', Value: 'v1' },
{ Key: 'Team', Value: 'DevOps' },
{ Key: 'Environment', Value: 'test' }
]),
AfterValue: JSON.stringify([
{ Key: 'Version', Value: 'v2' },
{ Key: 'UpdateType', Value: 'InPlace' },
{ Key: 'Environment', Value: 'production' }
])
}
}
]
Action: 'Add',
LogicalResourceId: 'NewBucket',
ResourceType: 'AWS::S3::Bucket',
AfterContext:
'{"BucketName":"my-bucket","Versioning":{"Status":"Enabled"}}'
}
}
],
totalChanges: 1,
truncated: false
})

const markdown = generateChangeSetMarkdown(changesSummary)
displayChangeSet(changesSummary, 1, true)

expect(markdown).toContain('**Tags:**')
expect(markdown).toContain('**Tags.Environment:** `test` → `production`')
expect(markdown).toContain('**Tags.Team:** `DevOps` → (removed)')
expect(markdown).toContain('**Tags.UpdateType:** (added) → `InPlace`')
expect(markdown).toContain('**Tags.Version:** `v1` → `v2`')
expect(core.info).toHaveBeenCalledWith(
expect.stringContaining('Properties:')
)
expect(core.info).toHaveBeenCalledWith(
expect.stringContaining('BucketName')
)
})

test('diffs nested objects correctly', () => {
test('displays BeforeContext for Remove actions in console output', () => {
const changesSummary = JSON.stringify({
changes: [
{
Type: 'Resource',
ResourceChange: {
Action: 'Modify',
LogicalResourceId: 'MyResource',
Action: 'Remove',
LogicalResourceId: 'OldBucket',
ResourceType: 'AWS::S3::Bucket',
BeforeContext: '{"BucketName":"old-bucket"}'
}
}
],
totalChanges: 1,
truncated: false
})

displayChangeSet(changesSummary, 1, true)

expect(core.info).toHaveBeenCalledWith(
expect.stringContaining('Properties:')
)
expect(core.info).toHaveBeenCalledWith(
expect.stringContaining('BucketName')
)
})

test('handles invalid JSON in AfterContext gracefully', () => {
const changesSummary = JSON.stringify({
changes: [
{
Type: 'Resource',
ResourceChange: {
Action: 'Add',
LogicalResourceId: 'NewResource',
ResourceType: 'AWS::Custom::Resource',
Replacement: 'False',
Scope: ['Properties'],
Details: [
{
Target: {
Attribute: 'Properties',
Name: 'Config',
RequiresRecreation: 'Never',
BeforeValue: JSON.stringify({
Setting: 'old',
Nested: { Value: 'a' }
}),
AfterValue: JSON.stringify({
Setting: 'new',
Nested: { Value: 'b' }
})
}
}
]
AfterContext: 'invalid-json{'
}
}
],
totalChanges: 1,
truncated: false
})

const markdown = generateChangeSetMarkdown(changesSummary)
displayChangeSet(changesSummary, 1, true)

expect(markdown).toContain('**Config.Setting:** `old` → `new`')
expect(markdown).toContain('**Config.Nested.Value:** `a` → `b`')
expect(core.info).toHaveBeenCalledWith(
expect.stringContaining('invalid-json{')
)
})

test('handles generic arrays as JSON strings', () => {
test('handles invalid JSON in BeforeContext gracefully', () => {
const changesSummary = JSON.stringify({
changes: [
{
Type: 'Resource',
ResourceChange: {
Action: 'Modify',
LogicalResourceId: 'MyResource',
Action: 'Remove',
LogicalResourceId: 'OldResource',
ResourceType: 'AWS::Custom::Resource',
Replacement: 'False',
Scope: ['Properties'],
Details: [
{
Target: {
Attribute: 'Properties',
Name: 'Items',
RequiresRecreation: 'Never',
BeforeValue: JSON.stringify(['a', 'b']),
AfterValue: JSON.stringify(['a', 'c'])
}
}
]
BeforeContext: 'invalid-json{'
}
}
],
totalChanges: 1,
truncated: false
})

const markdown = generateChangeSetMarkdown(changesSummary)
displayChangeSet(changesSummary, 1, true)

expect(markdown).toContain('**Items:**')
expect(markdown).toContain('["a","b"]')
expect(markdown).toContain('["a","c"]')
expect(core.info).toHaveBeenCalledWith(
expect.stringContaining('invalid-json{')
)
})

test('handles array additions and removals', () => {
test('generates diff view for resources with BeforeContext/AfterContext', () => {
const changesSummary = JSON.stringify({
changes: [
{
Type: 'Resource',
ResourceChange: {
Action: 'Modify',
LogicalResourceId: 'MyResource',
ResourceType: 'AWS::Custom::Resource',
LogicalResourceId: 'MyTopic',
ResourceType: 'AWS::SNS::Topic',
Replacement: 'False',
Scope: ['Properties'],
Details: [
{
Target: {
Attribute: 'Properties',
Name: 'NewList',
RequiresRecreation: 'Never',
AfterValue: JSON.stringify(['x', 'y'])
}
},
{
Target: {
Attribute: 'Properties',
Name: 'OldList',
RequiresRecreation: 'Never',
BeforeValue: JSON.stringify(['a', 'b'])
}
BeforeContext: JSON.stringify({
Properties: {
DisplayName: 'old-name',
Tags: [{ Key: 'Env', Value: 'dev' }]
}
]
}),
AfterContext: JSON.stringify({
Properties: {
DisplayName: 'new-name',
Tags: [{ Key: 'Env', Value: 'prod' }]
}
})
}
}
],
Expand All @@ -625,36 +606,38 @@ describe('Change Set Formatter', () => {

const markdown = generateChangeSetMarkdown(changesSummary)

expect(markdown).toContain('**NewList:** (added) → `["x","y"]`')
expect(markdown).toContain('**OldList:** `["a","b"]` → (removed)')
expect(markdown).toContain('```diff')
expect(markdown).toContain('-')
expect(markdown).toContain('+')
})

test('handles primitive value additions and removals', () => {
test('shows recreation warnings in diff view', () => {
const changesSummary = JSON.stringify({
changes: [
{
Type: 'Resource',
ResourceChange: {
Action: 'Modify',
LogicalResourceId: 'MyResource',
ResourceType: 'AWS::Custom::Resource',
Replacement: 'False',
Scope: ['Properties'],
LogicalResourceId: 'MyParam',
ResourceType: 'AWS::SSM::Parameter',
Replacement: 'True',
BeforeContext: JSON.stringify({
Properties: {
Name: '/old/path',
Value: 'old'
}
}),
AfterContext: JSON.stringify({
Properties: {
Name: '/new/path',
Value: 'new'
}
}),
Details: [
{
Target: {
Attribute: 'Properties',
Name: 'NewProp',
RequiresRecreation: 'Never',
AfterValue: 'new-value'
}
},
{
Target: {
Attribute: 'Properties',
Name: 'OldProp',
RequiresRecreation: 'Never',
BeforeValue: 'old-value'
Name: 'Name',
RequiresRecreation: 'Always'
}
}
]
Expand All @@ -667,8 +650,8 @@ describe('Change Set Formatter', () => {

const markdown = generateChangeSetMarkdown(changesSummary)

expect(markdown).toContain('**NewProp:** (added) → `new-value`')
expect(markdown).toContain('**OldProp:** `old-value` → (removed)')
expect(markdown).toContain('```diff')
expect(markdown).toContain('⚠️ Requires recreation: Always')
})

test('displays AfterContext for Add actions in console output', () => {
Expand Down
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