Golang Spf13 Viper

[
  {
    "id": 1,
    "name": "env-key-replacer-nested-keys",
    "description": "Tests SetEnvKeyReplacer for nested keys with dots mapping to underscore env vars",
    "prompt": "I'm using viper in my Go service. I have a config key 'database.host' that should be configurable via an env var. I've set AutomaticEnv() and SetEnvPrefix('APP'). My env var APP_DATABASE_HOST is set but viper returns the default. What's wrong?",
    "trap": "Without the skill, the model may suggest checking the env var name, case sensitivity, or re-reading the config. The root cause is the missing SetEnvKeyReplacer — viper looks for APP_DATABASE.HOST (dot preserved), not APP_DATABASE_HOST.",
    "assertions": [
      {
        "id": "1.1",
        "text": "Identifies the root cause as missing SetEnvKeyReplacer"
      },
      {
        "id": "1.2",
        "text": "Explains that viper preserves the dot in 'database.host' when looking up the env var"
      },
      {
        "id": "1.3",
        "text": "Provides the fix: viper.SetEnvKeyReplacer(strings.NewReplacer(\".\", \"_\"))"
      },
      {
        "id": "1.4",
        "text": "Shows that the full setup requires prefix + replacer + AutomaticEnv together"
      },
      {
        "id": "1.5",
        "text": "Does NOT suggest renaming the config key to avoid dots"
      }
    ]
  },
  {
    "id": 2,
    "name": "sub-returns-nil",
    "description": "Tests that viper.Sub() returns nil when the key doesn't exist and must be nil-checked",
    "prompt": "I'm using viper.Sub('database') in my Go service to get a sub-viper for database config, then calling sub.Unmarshal(&dbCfg). Occasionally the service panics with a nil pointer dereference. What's happening?",
    "trap": "Without the skill, the model may suggest checking the config file format or adding error handling to Unmarshal. The root cause is Sub() returning nil when the 'database' key doesn't exist, and nil.Unmarshal panics.",
    "assertions": [
      {
        "id": "2.1",
        "text": "Identifies that viper.Sub() returns nil when the key doesn't exist"
      },
      {
        "id": "2.2",
        "text": "Shows adding a nil check: if sub := viper.Sub(\"database\"); sub != nil { ... }"
      },
      {
        "id": "2.3",
        "text": "Suggests returning a clear error or using defaults when sub is nil"
      },
      {
        "id": "2.4",
        "text": "Does NOT suggest checking err from Sub() (it returns no error, only nil)"
      },
      {
        "id": "2.5",
        "text": "Optionally suggests UnmarshalKey(\"database\", &dbCfg) as an alternative that avoids Sub() entirely"
      }
    ]
  },
  {
    "id": 3,
    "name": "config-file-not-found-graceful",
    "description": "Tests graceful handling of ConfigFileNotFoundError for optional config files",
    "prompt": "My Go service uses viper to read a config file. When users run it without a config file, it crashes with 'Config File config not found in ...'. The config file should be optional. How do I fix this?",
    "trap": "Without the skill, the model may suggest pre-checking if the file exists before calling ReadInConfig, or using os.Stat. The correct pattern is errors.As with viper.ConfigFileNotFoundError.",
    "assertions": [
      {
        "id": "3.1",
        "text": "Uses errors.As(err, &notFound) with *viper.ConfigFileNotFoundError"
      },
      {
        "id": "3.2",
        "text": "Only propagates errors that are NOT ConfigFileNotFoundError"
      },
      {
        "id": "3.3",
        "text": "Continues execution normally when the config file is not found"
      },
      {
        "id": "3.4",
        "text": "Does NOT use os.Stat or file existence check as the solution"
      },
      {
        "id": "3.5",
        "text": "Does NOT ignore all errors from ReadInConfig (real errors like bad YAML should still propagate)"
      }
    ]
  },
  {
    "id": 4,
    "name": "global-viper-test-pollution",
    "description": "Tests viper.New() for test isolation