Commands/Merge-SqlMigrations.ps1
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<#
Copyright (C) 2020 Jeffrey Sharp Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. #> function Merge-SqlMigrations { <# .SYNOPSIS Merges a list of locally-defined migrations with a list of migrations already applied to a target database. Returns an ordered dictionary of migrations, keyed by migration name. #> [OutputType([System.Collections.Specialized.OrderedDictionary])] param ( # Locally-defined migrations. [Parameter(Mandatory, Position=0)] [AllowEmptyCollection()] [object[]] $SourceMigrations, # Migrations already applied to the target database. [Parameter(Mandatory, Position=1)] [AllowEmptyCollection()] [object[]] $TargetMigrations ) $Comparer = [StringComparer]::OrdinalIgnoreCase $Migrations = [ordered] @{} $SourceItems = $SourceMigrations.GetEnumerator() $TargetItems = $TargetMigrations.GetEnumerator() $HasSource = $SourceItems.MoveNext() $HasTarget = $TargetItems.MoveNext() while ($HasSource -or $HasTarget) { # Decide which migration comes next: source, target, or both $Comparison = if (!$HasSource) { +1 } <# Use TargetMigration #> ` elseif (!$HasTarget) { -1 } <# Use SourceMigration #> ` else { $Comparer.Compare($SourceItems.Current.Name, $TargetItems.Current.Name) } # Consume that/those migration(s), potentionally merging switch ($Comparison) { { $_ -lt 0 } { # Use SourceMigration $Migration = $SourceItems.Current | Copy-SqlMigrationObject $HasSource = $SourceItems.MoveNext() Write-Host (" (s--0) {0}" -f $Migration.Name) break } { $_ -gt 0 } { # Use TargetMigration $Migration = $TargetItems.Current | Copy-SqlMigrationObject $HasTarget = $TargetItems.MoveNext() Write-Host (" (-t-{1}) {0}" -f $Migration.Name, $Migration.State) break } default { # Merge TargetMigration into SourceMigration $Migration = $SourceItems.Current | Copy-SqlMigrationObject $Migration.State = $TargetItems.Current.State $Migration.HasChanged = $TargetItems.Current.Hash -and $TargetItems.Current.Hash -ne $Migration.Hash $HasSource = $SourceItems.MoveNext() $HasTarget = $TargetItems.MoveNext() Write-Host ( " (st{2}{1}) {0}" -f $Migration.Name, $Migration.State, $(if ($Migration.HasChanged) {'!'} else {'='}) ) break } } # Add to result $Migrations.Add($Migration.Name, $Migration) } # Return result $Migrations } |