Compare-DbaDbSchema - Add new command for schema comparison via sqlpackage

[andreasjordan]

Implements Compare-DbaDbSchema using sqlpackage's DeployReport action to compare a source DACPAC against a target database or DACPAC file, returning structured schema difference objects.

Closes #5342

Generated with Claude Code

[andreasjordan]

@claude tests fail.

Output:

Running C:\github\dbatools\tests\Compare-DbaDbSchema.Tests.ps1 ...[11:22:16][Compare-DbaDbSchema] sqlpackage failed: *** Operation DeployReport requires a target database name.
[11:22:17][Compare-DbaDbSchema] sqlpackage failed: *** Operation DeployReport requires a target database name.
Completed C:\github\dbatools\tests\Compare-DbaDbSchema.Tests.ps1 in 76670ms


Failed tests summary:
Path           : Compare-DbaDbSchema/Compare DACPAC against a live database/Returns schema differences when source has objects not in target
Name           : It Returns schema differences when source has objects not in target
Result         : Failed
Message        : ErrorRecord: Expected 'Table' to be found in collection SqlTable, but it was not found.
StackTrace     : 
RawErrorRecord : Expected 'Table' to be found in collection SqlTable, but it was not found.
Path           : Compare-DbaDbSchema/Compare two DACPAC files/Keeps the report file when -KeepReport is specified
Name           : It Keeps the report file when -KeepReport is specified
Result         : Failed
Message        : ErrorRecord: Expected a value, but got $null or empty.
StackTrace     : 
RawErrorRecord : Expected a value, but got $null or empty.
Path           : Compare-DbaDbSchema/Compare two DACPAC files/Returns schema differences between two DACPAC files
Name           : It Returns schema differences between two DACPAC files
Result         : Failed
Message        : ErrorRecord: Expected a value, but got $null or empty.
StackTrace     : 
RawErrorRecord : Expected a value, but got $null or empty.

[claude]

Claude finished @andreasjordan's task in 1m 50s —— View job

---

Fixed test failures

• Read implementation and test files
• Diagnose the failures
• Fix the implementation
• Push changes

Two bugs fixed in Compare-DbaDbSchema.ps1:

1. DACPAC-to-DACPAC: missing /tdn: argument (public/Compare-DbaDbSchema.ps1:164)
   sqlpackage's DeployReport action requires a target database name even when the target is a DACPAC file (not a live database). Fixed by extracting the base filename of the target DACPAC and passing it as /tdn:.

2. Type field had "Sql" prefix (public/Compare-DbaDbSchema.ps1:213)
   sqlpackage reports types as SqlTable, SqlProcedure, etc. The test expected Table, and Table is also cleaner for end users. Fixed by stripping the leading "Sql" prefix with -replace "^Sql", "".
   |

[andreasjordan]

@claude tests fail.

Output:

Failed tests summary:
Path           : Compare-DbaDbSchema/Compare two DACPAC files/Keeps the report file when -KeepReport is specified
Name           : It Keeps the report file when -KeepReport is specified
Result         : Failed
Message        : ErrorRecord: Expected a value, but got $null or empty.
StackTrace     : 
RawErrorRecord : Expected a value, but got $null or empty.
Path           : Compare-DbaDbSchema/Compare two DACPAC files/Returns schema differences between two DACPAC files
Name           : It Returns schema differences between two DACPAC files
Result         : Failed
Message        : ErrorRecord: Expected a value, but got $null or empty.
StackTrace     : 
RawErrorRecord : Expected a value, but got $null or empty.

[claude]

Claude finished @andreasjordan's task in 1m 45s —— View job

---

Fixed remaining test failures

• Read failing test output
• Read implementation and test files
• Diagnose the failures
• Fix the test file
• Push changes

Root cause: Test state pollution — the "Returns no differences" test calls Publish-DbaDacPackage to populate $dbTargetName. The DACPAC-comparison tests then exported that now-populated DB, producing a DACPAC identical to source, so Compare-DbaDbSchema returned no differences.

Fix (tests/Compare-DbaDbSchema.Tests.ps1): Export the empty target DB to a DACPAC in the shared BeforeAll block, before any tests can modify it. The "Compare two DACPAC files" tests now use this pre-exported $emptyTargetDacpac variable directly.