default_config_filename setting not working, but MISE_DEFAULT_CONFIG_FILENAME env is

[ryanbrainard]

I'm trying to make my default config filename .mise.toml (instead of mise.toml). I tried setting this with mise settings set default_config_filename .mise.toml, but it does not work and continues to create mise.toml file by default. However, if I use the MISE_DEFAULT_CONFIG_FILENAME env var, it works and creates .mise.toml files by default.

When running with MISE_TRACE and then running mise use go@1.22 in a dir that does not have a config file yet, I can see it show:

TRACE  1 [src/config/settings.rs:198] Settings: Settings {
...
default_config_filename: ".mise.toml",

but then it still does this:

TRACE  1 [src/file.rs:178] write ~/Development/my-project/mise.toml

Repeating the same with the MISE_DEFAULT_CONFIG_FILENAME env var set works as expected.

mise doctor output

version: 2025.7.27 macos-arm64 (2025-07-24)
activated: yes
shims_on_path: no
self_update_available: no

build_info:
  Target: aarch64-apple-darwin
  Features: DEFAULT, NATIVE_TLS, SELF_UPDATE
  Built: Thu, 24 Jul 2025 16:16:31 +0000
  Rust Version: rustc 1.88.0 (6b00bc388 2025-06-23) (Homebrew)
  Profile: release

shell:
  /opt/homebrew/bin/zsh
  zsh 5.9 (arm-apple-darwin24.0.0)

aqua:
  baked in registry tools: 0 – aqua registry tools are not compiled into mise, will be fetched dynamically from https://mise-versions.jdx.dev

dirs:
  cache: ~/.cache/mise
  config: ~/.config/mise
  data: ~/.local/share/mise
  shims: ~/.local/share/mise/shims
  state: ~/.local/state/mise

config_files:
  ~/.config/mise/config.toml

ignored_config_files: (none)

backends:
  aqua
  asdf
  cargo
  core
  dotnet
  gem
  github
  gitlab
  go
  npm
  pipx
  spm
  http
  ubi
  vfox

plugins:

toolset:
  aqua:GoogleContainerTools/skaffold@2.16.0
  aqua:ahmetb/kubectx@0.9.5
  aqua:aws/aws-cli@2.27.45
  aqua:derailed/k9s@0.50.6
  aqua:hashicorp/terraform@1.12.1
  aqua:kubernetes-sigs/kubebuilder@4.6.0
  aqua:kubernetes/kubectl@1.33.1
  aqua:open-policy-agent/opa@1.5.1
  aqua:pnpm/pnpm@10.11.1
  core:go@1.24.5
  core:node@24.1.0
  core:python@3.13.3
  core:ruby@3.4.4
  ubi:jdx/usage@2.1.1

path:
  ~/.local/share/mise/installs/go/1.24.5/bin
  ~/.local/share/mise/installs/k9s/0.50.6
  ~/.local/share/mise/installs/kubebuilder/4.6.0
  ~/.local/share/mise/installs/kubectl/1.33.1
  ~/.local/share/mise/installs/kubectx/0.9.5
  ~/.local/share/mise/installs/node/24.1.0/bin
  ~/.local/share/mise/installs/opa/1.5.1
  ~/.local/share/mise/installs/python/3.13.3/bin
  ~/.local/share/mise/installs/ruby/3.4.4/bin
  ~/.local/share/mise/installs/terraform/1.12.1
  ~/.local/share/mise/installs/skaffold/2.16.0
  ~/.local/share/mise/installs/usage/2.1.1
  ~/.local/share/mise/installs/pnpm/10.11.1
  ~/.local/share/mise/installs/aws/2.27.45/aws-cli.pkg/Payload/aws-cli
  ~/.krew/bin
  /opt/homebrew/opt/gnu-tar/libexec/gnubin
  /opt/homebrew/bin
  /opt/homebrew/sbin
  /usr/local/bin
  /System/Cryptexes/App/usr/bin
  /usr/bin
  /bin
  /usr/sbin
  /sbin
  /var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin
  /var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin
  /var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin
  /usr/local/MacGPG2/bin
  /Applications/Wireshark.app/Contents/MacOS
  /opt/podman/bin
  /Applications/iTerm.app/Contents/Resources/utilities
  ~/.bin
  ~/.local/bin
  ~/go/bin
  ~/Library/Application Support/JetBrains/Toolbox/scripts

env_vars:
  MISE_SHELL=zsh

settings:
  default_config_filename              ".mise.toml" ~/.config/mise/config.toml
  idiomatic_version_file_enable_tools  ["ruby"]     ~/.config/mise/config.toml

No problems found

[jdx]

we should remove this as a setting in the docs, anything that affects the order config files load must be env vars

[ryanbrainard]

Ah, I wasn't going crazy then. Thanks for the quick response!

[ryanbrainard]

On this topic, is there any problem if I set MISE_DEFAULT_CONFIG_FILENAME=.tool-versions, aside from the limitations of .tool-versions format? It seems to work, but wanted to ask. Most of my team is still on asdf, so trying to stay compatible with them.

[jdx]

in theory there shouldn't be, in practice maybe. It's just not well trodden.