Set KAMAL_DESTINATION before rendering the config for an alias

[viktorianer]

kamal <alias> -d staging resolves the alias through Commander#resolve_alias, which calls Configuration.load_raw_config before any Configuration.create_from. Only create_from sets ENV["KAMAL_DESTINATION"], so the ERB in deploy.yml renders without the destination the command was given.

A config that reads the destination at render time then resolves the alias against the wrong values. A common shape is loading a per-destination env file:

<% require "dotenv"; Dotenv.load(".env.#{ENV.fetch("KAMAL_DESTINATION", "production")}") %>

With an alias, this loads .env.production for -d staging. It raises when that file is absent, or silently renders production values before the real command runs with the staging config. The same command without an alias renders correctly.

ENV["KAMAL_DESTINATION"] is now set in load_raw_config, which both create_from and resolve_alias call.

The new test in test/cli/main_test.rb runs an alias whose command renders KAMAL_DESTINATION. It fails without the change, because the command is rendered as bin/console, not bin/console world.

[Copilot]

🟢 Approved

The change addresses the alias rendering order while preserving existing configuration behavior and adding focused regression coverage.

0 open findings

What changed in this PR

Sets KAMAL_DESTINATION before rendering configuration, ensuring aliases use destination-specific ERB values.

Changes:

• Moves destination environment setup into load_raw_config.
• Adds an alias integration test and destination fixtures.

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File	Description
lib/​kamal/​configuration.rb	Sets the destination before ERB rendering.
test/​cli/​main_test.rb	Tests destination-aware alias rendering.
test/​fixtures/​deploy_with_destination_aliases.yml	Defines an ERB-based alias fixture.
test/​fixtures/​deploy_with_destination_aliases.world.yml	Supplies the destination-specific server fixture.

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