fix(task): pass env to usage parser for env-backed arguments

[jdx]

Summary

• Fixes env-backed arguments are empty usage#468 - env-backed arguments now read from shell environment
• The parse_usage_spec_and_init_env function was using usage::parse() without passing the environment, causing env="VAR_NAME" attributes to always fall back to defaults

Test plan

• Added e2e test test_task_usage_env_inherited that verifies:
  • env= reads from inherited shell environment
  • Explicit args override env defaults
  • Falls back to default when env not set

🤖 Generated with Claude Code

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Note

Ensures usage specs respect environment-backed defaults when running tasks.

• In task_executor.rs, parse_usage_spec_and_init_env now uses usage::Parser::new(&spec).with_env(env).parse(...) so env="VAR" args/flags read from the inherited environment instead of always defaulting
• Adds e2e test e2e/tasks/test_task_usage_env_inherited verifying env inheritance, explicit arg override, and fallback to default

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[Copilot]

Pull request overview

This PR fixes a bug where usage spec arguments with env="VAR_NAME" attributes were not reading from the shell environment, always falling back to defaults instead. The fix passes the environment map to the usage parser so it can properly resolve environment-backed arguments.

Changes:

• Modified task executor to pass environment variables to the usage parser
• Added comprehensive e2e test verifying environment inheritance behavior

Reviewed changes

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

File	Description
src/task/task_executor.rs	Updated to pass env map to usage::Parser for resolving env-backed arguments
e2e/tasks/test_task_usage_env_inherited	Added test verifying env inheritance, explicit arg override, and default fallback

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[Copilot]

The escape sequence in the echo command may not work as intended. The variable reference should be $usage_host without the backslash escape, or use single quotes in the HEREDOC to prevent shell expansion.

Suggested change

	cat <<EOF >mise.toml
	[tasks.test]
	usage = '''
	arg "[host]" env="TEST_HOST" default="localhost"
	'''
	run = 'echo "Host: \${usage_host}"'
	cat <<'EOF' >mise.toml
	[tasks.test]
	usage = '''
	arg "[host]" env="TEST_HOST" default="localhost"
	'''
	run = 'echo "Host: ${usage_host}"'

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Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[github-actions]

Hyperfine Performance

mise x -- echo

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.1.8 x -- echo	20.3 ± 0.4	19.4	21.4	1.00
mise x -- echo	20.7 ± 0.4	19.8	23.3	1.02 ± 0.03

mise env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.1.8 env	19.9 ± 0.5	18.9	26.5	1.00
mise env	20.8 ± 0.7	19.6	25.3	1.05 ± 0.05

mise hook-env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.1.8 hook-env	20.1 ± 0.7	19.2	26.9	1.00
mise hook-env	20.6 ± 0.9	19.7	29.3	1.03 ± 0.06

mise ls

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.1.8 ls	17.8 ± 0.6	16.8	26.2	1.00
mise ls	18.1 ± 0.4	17.3	20.2	1.01 ± 0.04

xtasks/test/perf

Command	mise-2026.1.8	mise	Variance
install (cached)	112ms	111ms	+0%
ls (cached)	68ms	68ms	+0%
bin-paths (cached)	72ms	72ms	+0%
task-ls (cached)	284ms	296ms	-4%