tfenv: Instructions file for GitHub Copilot

Bash Coding Standards — tfenv

These standards apply to ALL bash scripts in the tfenv repository. Read this entire document BEFORE writing or modifying any bash code.

Mandatory Pre-Write Verification

Before writing ANY bash code, verify you understand these rules. Violations caught after writing waste time — get it right first.

Shell Setup

Every script in libexec/ contains its own boilerplate for resolving TFENV_ROOT and sourcing helpers. This is intentional — each script must be executable in isolation. Do NOT refactor this into a shared loader.

#!/usr/bin/env bash
set -uo pipefail;

• Shebang: #!/usr/bin/env bash (exact format)
• Strict mode: set -uo pipefail; — NEVER use set -e
• The project does NOT use shellcheck — this is a deliberate choice

Indentation and Formatting

• 2-space indentation throughout (no tabs)
• Terminate ALL statements with a semicolon (;) where syntactically correct
• Include vim modeline at end of new scripts: # vim: set syntax=bash tabstop=2 softtabstop=2 shiftwidth=2 expandtab smarttab :

Variables

• ALL variable references use braces: ${variable} (never $variable)
• Script-local variables use lowercase: ${version}, ${remote}
• Environment variables use UPPERCASE: ${TFENV_ROOT}, ${TFENV_ARCH}
• Always quote variable expansions: "${variable}"
• Quote entire strings containing variables: "${dir}/file" NOT "${dir}"/file
• Use ${var:-default} for optional variables (scripts run with set -u)

Quoting

• Single-quote strings unless variable expansion is needed
• Double-quote strings that contain variable expansion
• NEVER use unescaped ! inside double-quoted strings (bash history expansion)

Command Substitution

• Use $(...) NOT backticks

Error Handling

• NEVER use set -e — handle errors explicitly
• Use the project's existing error patterns:
  • error_and_die for fatal errors (available via lib/helpers.sh)
  • Inline || pattern for simple cases:

    some_command || error_and_die "Failed to do thing";
    

• Note: error_and_die does NOT exist in the test context — tests use error_and_proceed instead