avoid printing env vars conflict warnings if there is no conflict

[jordanstephens]

Description

To reduce noise, lets avoid printing this warning if the value in the environment and the value in the stack are the same

Linked Issues

Checklist

• I have performed a self-review of my code
• I have added appropriate tests
• I have updated the Defang CLI docs and/or README to reflect my changes, if necessary

Summary by CodeRabbit

• Bug Fixes
  • Environment values are now preserved and applied using their actual values rather than as simple presence flags.
  • Conflict detection now warns only when environment-provided values differ from stack values, reducing false positives.
  • Improved application logic for when environment variables are set or overridden, with clearer warning text reflecting value sources.

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[coderabbitai]

📝 Walkthrough

Walkthrough

The LoadStackEnv function in stacks.go now preserves environment variable values by switching from map[string]bool to map[string]string, using strings.Cut to extract key/value pairs, updating conflict detection to compare values, and adjusting when values are applied and warnings emitted.

Changes

Cohort / File(s)	Summary
Environment Variable Value Handling src/pkg/stacks/stacks.go	LoadStackEnv changed from map[string]bool to map[string]string; uses strings.Cut to extract key/value; conflict check now compares envValue != value; apply logic sets values when absent or when overload allowed; warning text updated to reference the environment value.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• avoid double stack loading #1800 — Adjusts caller-side usage of LoadStackEnv and moves/removes wrappers, directly related to the function signature/semantics change in this PR.

Poem

🐰 I hopped through envs with scissors bright,
I cut the pairs and kept each light,
No longer true/false in the air,
Values settle, tidy and fair,
Hooray — keys and values hold tight!

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title directly and clearly summarizes the main change: suppressing environment variable conflict warnings when there is no actual conflict, which aligns with the core objective to reduce noise from false-positive warnings.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

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✨ Finishing touches

• 📝 Generate docstrings

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 golangci-lint (2.5.0)

level=warning msg="[linters_context] running gomodguard failed: unable to read module file go.mod: current working directory must have a go.mod file: if you are not using go modules it is suggested to disable this linter"
level=error msg="[linters_context] typechecking error: pattern ./...: directory prefix . does not contain main module or its selected dependencies"

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@src/pkg/stacks/stacks.go`:
- Around line 229-234: The warning is emitted even when the env var doesn't
exist because currentEnv[key] returns "" for missing keys; change the logic in
the loop over paramsMap to perform the existence check first (use the lookup
form like "val, ok := currentEnv[key]") and only call term.Warnf when ok is true
and val != value and !overload; keep the existing branch that sets the env via
os.Setenv when the key is missing or overload is true so behavior remains the
same.