TODO(adamb): this function is used for two quite different inputs: program name and language ID.

WithDebug enables additional debug information.

WithDocker provides a docker client for docker commands.

ProgramResolverModeAuto is a default which prompts for all unresolved variables.

ProgramResolverModePromptAll always prompts even if variables are resolved.

ProgramResolverModeSkipAll does not prompt even if variables are unresolved.

ProgramResolverStatusResolved indicates a variable is resolved.

ProgramResolverStatusUnresolved indicates a variable is unresolved.

ProgramResolverStatusUnresolvedWithMessage indicates a variable is unresolved but it has a message.

ProgramResolverStatusUnresolvedWithPlaceholder indicates a variable is unresolved but it has a placeholder.

ProgramResolverStatusUnresolvedWithSecret indicates a variable is unresolved and needs to be treated with sensitivity.

SessionListCapacity is a maximum number of sessions stored in a single SessionList.

ProgramResolver uses a list of ProgramResolverSource to resolve environment variables found in a shell program.

Session is an object which lifespan contains multiple executions.

ProgramConfig contains a serializable configuration for a command.