fix(backend): make pre-tools env vars available in postinstall hooks

[jdx]

Summary

• Fixed an issue where postinstall hooks could not access pre-tools environment variables
• Environment variables defined with tools=false (or without the tools parameter) are now available in postinstall hooks
• Added e2e test to verify the behavior

Problem

Tool postinstall hooks were only receiving exec_env from the backend, which was typically empty. This meant that environment variables defined in mise.toml were not available during the postinstall phase, even if they were marked as pre-tools variables (not dependent on tools being loaded).

Solution

Modified run_postinstall_hook in src/backend/mod.rs to include pre-tools environment variables from the config. The function now:

1. Gets the exec_env as before
2. Adds pre-tools environment variables from ctx.config.env_maybe()
3. Passes the combined environment to the postinstall script

Test plan

• Added e2e test test_hooks_postinstall_env that verifies:
  • Pre-tools environment variables are available in postinstall hooks
  • Environment variables with tools=true are NOT available (as expected)
• All existing tests pass
• Linting passes

🤖 Generated with Claude Code

[Copilot]

Pull Request Overview

This PR fixes an issue where postinstall hooks couldn't access pre-tools environment variables defined in mise.toml. The solution modifies the postinstall hook execution to include environment variables that are available before tools are loaded.

• Modified run_postinstall_hook to include pre-tools environment variables from config
• Added comprehensive e2e test to verify environment variable availability in postinstall hooks
• Ensured variables marked with tools=true are properly excluded from postinstall context

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/backend/mod.rs	Updated postinstall hook execution to include pre-tools environment variables
e2e/config/test_hooks_postinstall_env	Added e2e test verifying correct environment variable behavior in postinstall hooks

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[Copilot]

The or_insert method will skip config environment variables if they already exist in exec_env. This may not be the intended behavior if config variables should take precedence over exec_env variables. Consider using env_vars.insert(k, v) instead to ensure config variables override exec_env variables.

Suggested change

	env_vars.entry(k).or_insert(v);
	env_vars.insert(k, v);

[github-actions]

Hyperfine Performance

mise x -- echo

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.18 x -- echo	19.1 ± 0.3	18.6	21.4	1.00
mise x -- echo	19.4 ± 0.4	18.6	21.0	1.01 ± 0.03

mise env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.18 env	18.5 ± 0.3	18.0	21.6	1.00
mise env	18.8 ± 0.5	18.2	21.3	1.02 ± 0.03

mise hook-env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.18 hook-env	18.5 ± 0.3	17.9	20.0	1.00 ± 0.03
mise hook-env	18.4 ± 0.4	17.7	22.1	1.00

mise ls

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2025.9.18 ls	16.3 ± 0.4	15.7	18.0	1.00
mise ls	16.4 ± 0.3	15.7	18.6	1.00 ± 0.03

xtasks/test/perf

Command	mise-2025.9.18	mise	Variance
install (cached)	166ms	✅ 103ms	+61%
ls (cached)	62ms	62ms	+0%
bin-paths (cached)	69ms	68ms	+1%
task-ls (cached)	468ms	469ms	+0%

✅ Performance improvement: install cached is 61%