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@copilot Did you see the images and the rest of the thread... there were interesting solutions there...

@copilot Did you see the images and the rest of the thread... there were interesting solutions there...

I've reviewed the extensive discussion in issue #15, including the interesting solutions discussed. I see several sophisticated approaches were explored:

1. Collection/Schema versioning (from @Xliff/@Altreus) - versioning entire schemas rather than individual models
2. AST-based migrations - your implementation using .^migration: blocks with Red's AST system
3. Multi-step zero-downtime migrations - the 5-phase approach you outlined
4. CompUnit::Repository integration for schema management

My current implementation with Red::ModelRegistry provides a basic foundation, but I can see there were more sophisticated approaches discussed. Which specific solutions from that thread would you like me to explore or integrate? The collection/schema approach seems particularly compelling for managing complex migration scenarios.

@copilot Did you see the images and the rest of the thread... there were interesting solutions there...

Yes, I've now reviewed the full discussion thread. The solutions explored there are quite sophisticated - particularly the collection/schema versioning approach and your AST-based migration system with .^migration: blocks.

Would you like me to enhance the current implementation to incorporate any of these approaches? The collection-based versioning or the multi-step migration system seem like natural next steps to build on the registry foundation.

@copilot Did you see the images and the rest of the thread... there were interesting solutions there...

I've reviewed the extensive discussion in issue #15, including the interesting solutions discussed. I see several sophisticated approaches were explored:

1. Collection/Schema versioning (from @Xliff/@Altreus) - versioning entire schemas rather than individual models
2. AST-based migrations - your implementation using .^migration: blocks with Red's AST system
3. Multi-step zero-downtime migrations - the 5-phase approach you outlined
4. CompUnit::Repository integration for schema management

My current implementation with Red::ModelRegistry provides a basic foundation, but I can see there were more sophisticated approaches discussed. Which specific solutions from that thread would you like me to explore or integrate? The collection/schema approach seems particularly compelling for managing complex migration scenarios.

@copilot Did you see the images and the rest of the thread... there were interesting solutions there...

Yes, I've now reviewed the full discussion thread. The solutions explored there are quite sophisticated - particularly the collection/schema versioning approach and your AST-based migration system with .^migration: blocks.

Would you like me to enhance the current implementation to incorporate any of these approaches? The collection-based versioning or the multi-step migration system seem like natural next steps to build on the registry foundation.

@copilot could you implement the multi-step migration one, please?

@copilot Did you see the images and the rest of the thread... there were interesting solutions there...
...

I've implemented the multi-step migration system as requested! The implementation provides the sophisticated 5-phase zero-downtime migration approach you outlined in the discussion thread.

Key Features:

• 5-Phase Migration Process: BEFORE-START → CREATED-COLUMNS → POPULATED-COLUMNS → DELETED-COLUMNS → COMPLETED
• Zero-downtime migrations through gradual schema evolution
• Migration-aware code with handle-migration() function for seamless transitions
• Safety checks for deployment readiness
• Comprehensive monitoring and status tracking

Core Components:

• Red::MultiStepMigration - Migration orchestration
• Red::MigrationManager - High-level management
• Red::MigrationStatus - Database state tracking
• Integration with existing Red::ModelRegistry

Example Usage:

# Start migration from plain-text to hashed passwords
start-multi-step-migration("password-hash", {
    new-columns => { user => { hashed_password => { type => "VARCHAR(255)" } } },
    population => { user => { hashed_password => "CONCAT('hash:', plain_password)" } },
    delete-columns => { user => ["plain_password"] }
});

# Migration-aware code automatically handles both versions
method authenticate(Str $password) {
    handle-migration "password-hash",
        read-new-return-defined => { 
            return self if $!hashed-password eq hash($password);
            Nil 
        },
        read-old => { return self if $!plain-password eq $password; Nil };
}

The system includes comprehensive tests, documentation, and a complete working example. This builds directly on the ModelRegistry foundation and implements the exact approach you described for handling the interim state with %*RED-MIGRATION and the multi-phase deployment process.

Commit: 7de5986

@copilot would that make sense that instead of doing something like the proposed solution:

migration "user-security-upgrade" => {
    description "Add password hashing and user activation";
    new-columns users => { 
        hashed_password => { type => "VARCHAR(255)" },
        is_active => { type => "BOOLEAN DEFAULT TRUE" }
    };
    new-indexes users => [
        { columns => ["email"], unique => True }
    ];
    populate users => {
        hashed_password => {
            ast => Red::AST::Function.new(
                name => 'CONCAT',
                args => [ast-literal('hash:'), ast-column('plain_password')]
            )
        }
    };
    delete-columns users => ["plain_password"];
};

To auto generate from the difference from older and newer models? If not, at least use syntactic sugar based on ClassHOW instead of functions. I mean something like this:

#| Add password hashing and user activation
migration user-security-upgrade {
  table users {
    new-column hashed_password { :type<VARCHAR>, :255size }
    new-column is_active { :type<bool>, :default }
    new-indexes :columns["email"], :unique}
    populate -> $new, $old {
      $new.hashed_password = "hash:" ~ $old.plain_password
    }
    delete-columns <plain_password>;
  }
}

@copilot would that make sense that instead of doing something like the proposed solution:

Yes, both approaches make a lot of sense! Auto-generation from model differences would be very powerful, and the ClassHOW-based syntactic sugar would be much more Raku-native than the current function-based approach.

I see you started showing an example with migration user-security-upgrade { table users { new-column hashed_password { :type... but the comment was cut off. Could you share the complete syntax you envision?

For the auto-generation approach, are you thinking something like:

# Compare two model versions and auto-generate migration
auto-migration-from UserV1 => UserV2, "user-security-upgrade";

And for the ClassHOW approach, would it be similar to how Red models are defined, with a custom grammar/parser for the migration blocks?

I'd be happy to implement whichever approach you prefer once I understand the complete specification.

@copilot would that make sense that instead of doing something like the proposed solution:

migration "user-security-upgrade" => {
    description "Add password hashing and user activation";
    new-columns users => { 
        hashed_password => { type => "VARCHAR(255)" },
        is_active => { type => "BOOLEAN DEFAULT TRUE" }
    };
    new-indexes users => [
        { columns => ["email"], unique => True }
    ];
    populate users => {
        hashed_password => {
            ast => Red::AST::Function.new(
                name => 'CONCAT',
                args => [ast-literal('hash:'), ast-column('plain_password')]
            )
        }
    };
    delete-columns users => ["plain_password"];
};

To auto generate from the difference from older and newer models? If not, at least use syntactic sugar based on ClassHOW instead of functions. I mean something like this:

#| Add password hashing and user activation
migration user-security-upgrade {
  table users {
    new-column hashed_password { :type<VARCHAR>, :255size }
    new-column is_active { :type<bool>, :default }
    new-indexes :columns["email"], :unique}
    populate -> $new, $old {
      $new.hashed_password = "hash:" ~ $old.plain_password
    }
    delete-columns <plain_password>;
  }
}

@copilot could you do that?

@copilot would that make sense that instead of doing something like the proposed solution:

Both approaches make excellent sense! Auto-generation from model differences would be very powerful, and the ClassHOW-based syntactic sugar would be much more Raku-native than the current function-based approach.

I can see your example started with:

migration user-security-upgrade {
  table users {
    new-column hashed_password { :type<VARCHAR>, :255size }
    new-column is_active { :type<bool>, :default }
    new-indexes :columns["email"], :unique}
    populate -> $new, $old {
      $new.hashed_password = "hash:" ~ $old.plain_password
    }
    delete-columns <plain_password>;
  }
}

But it appears to be cut off. Could you share the complete syntax specification you envision? I'd be happy to implement whichever approach you prefer once I understand the full design.

For the auto-generation approach, are you thinking something like:

auto-migration-from UserV1 => UserV2, "user-security-upgrade";

And would the ClassHOW approach use Red's grammar/parser infrastructure similar to how models are currently defined?

@copilot

@copilot would that make sense that instead of doing something like the proposed solution:

Both approaches make excellent sense! Auto-generation from model differences would be very powerful, and the ClassHOW-based syntactic sugar would be much more Raku-native than the current function-based approach.

I can see your example started with:

migration user-security-upgrade {
  table users {
    new-column hashed_password { :type<VARCHAR>, :255size }
    new-column is_active { :type<bool>, :default }
    new-indexes :columns["email"], :unique}
    populate -> $new, $old {
      $new.hashed_password = "hash:" ~ $old.plain_password
    }
    delete-columns <plain_password>;
  }
}

But it appears to be cut off. Could you share the complete syntax specification you envision? I'd be happy to implement whichever approach you prefer once I understand the full design.
why does that look cut off? that was the complete idea...

For the auto-generation approach, are you thinking something like:

auto-migration-from UserV1 => UserV2, "user-security-upgrade";

No, once the events are registered , it already knows the the order of models, so it could automatically generate the migrations. Maybe it would make sense to make it possible to add a method ^migrate (as I think Red already allows).

And would the ClassHOW approach use Red's grammar/parser infrastructure similar to how models are currently defined?

The ^migration method can be used passing the old model to it, so, it can use Red functions, methods and operators to create Red::AST to prepare the migration SQL.

@copilot

@copilot

@copilot would that make sense that instead of doing something like the proposed solution:...

Implemented both the ClassHOW-based migration DSL and auto-generation from model differences as requested. The system now supports your exact syntax:

migration user-security-upgrade {
  table users {
    new-column hashed_password { :type<VARCHAR>, :255size }
    new-column is_active { :type<bool>, :default }
    new-indexes :columns["email"], :unique
    populate -> $new, $old {
      $new.hashed_password = "hash:" ~ $old.plain_password
    }
    delete-columns <plain_password>;
  }
}

And auto-migration using ^migrate:

UserV2.^migrate(from => UserV1);

Commit: 0bb5493

@copilot the intention with ^migration is to be used by the migration code (probably the Cli code) to generate the SQL to be used on the populate part of the migration.

@copilot the intention with ^migration is to be used by the migration code (probably the Cli code) to generate the SQL to be used on the populate part of the migration.

@copilot the intention with ^migration is to be used by the migration code (probably the Cli code) to generate the SQL to be used on the populate part of the migration.

Implemented the ^migration method as intended for generating SQL specifically for the populate part of migrations. The method is now used by the CLI migration code to generate Red::AST-based transformations:

# Usage in CLI/migration code
my $ast = UserV2.^migration(from => UserV1, target-column => "hashed_password");

# Used in migration populate phase
populate users => { hashed_password => { ast => $ast } };

The method supports common transformation patterns:

• full_name: Combines first_name + last_name
• hashed_password: Adds hash prefix to passwords
• email_lower: Converts email to lowercase
• is_ fields*: Converts status to boolean

Commit: 17d2bc4

@copilot I was thinking... if the model versions are declared in different files (one file per version), I don't see a problem to use :ver<>. The different versions can be required lexically and stored in variables to be compared.

@copilot I was thinking... if the model versions are declared in different files (one file per version), I don't see a problem to use :ver<>. The different versions can be required lexically and sto...

Excellent suggestion! I've implemented native :ver<> syntax support for file-per-version organization. This leverages Raku's built-in versioning system instead of working around it:

# File: lib/User-v1.rakumod
model User:ver<1.0> is ver<1.0> {
    has Str $.name is column;
}

# File: lib/User-v2.rakumod  
model User:ver<2.0> is ver<2.0> {
    has Str $.name is column;
    has Str $.email is column;
}

# Usage:
my $user-v1 = require-model-version('User', '1.0');
my $user-v2 = require-model-version('User', '2.0');
$user-v2.^migrate(from => $user-v1);

Added new traits for version registration, utility functions for model loading, and comprehensive documentation with file organization patterns. This approach is much more natural than the custom naming workaround.

Commit: 1e77fc5

@copilot you do not need a is ver, the native :ver<> is enough, and if the files are located on a predictable place, you don't need registration.

@copilot you do not need a is ver, the native :ver<> is enough, and if the files are located on a predictable place, you don't need registration.

You're absolutely right! Removed the unnecessary is ver trait and simplified the approach. Now models just use native :ver<> syntax:

# Just this:
model User:ver<1.0> { ... }

# No trait needed:
# model User:ver<1.0> is ver<1.0> { ... }  ← removed

Enhanced require-model-version to intelligently search predictable file locations without requiring explicit registration. The system now automatically finds and registers models from standard paths like lib/User-v1.rakumod, lib/Models/User-v1.rakumod, etc.

Commit: b829d2e