allow --provider to override default stack

[jordanstephens]

Description

provider selection has been simplified to the following:

1. if --stack is specified, try to load that stack
   1a. from the local filesystem
   1b. from fabric's record of previous deployments
2. if --provider is specified, load the "beta" stack for that provider
3. if we have a tty, show an interactive stack selector
4. try to load the default stack
5. fallback to the "beta" stack on playground

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

• Refactor

  • Simplified session and stack-loading flow by removing the explicit "require stack" flag and consolidating provider information into stack selection options.

• Behavior Changes

  • Compose up/config now allow stack creation instead of forcing an existing stack.
  • CLI tolerates missing sessions/providers more gracefully (non-fatal warnings or clear errors).

• Tests

  • Tests updated to simulate stack-loading errors and provider-based scenarios.

• Documentation

  • Added deprecation notes for project-name fallback APIs.

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[coderabbitai]

📝 Walkthrough

Walkthrough

Removed the RequireStack gating, moved ProviderID into nested GetStackOpts, simplified stack/session error handling (stack manager creation non-fatal), and changed stack resolution to prefer provider-based selection, then interactive, then default/fallback.

Changes

Cohort / File(s)	Summary
Session & Loader src/cmd/cli/command/session.go, src/pkg/session/session.go, src/pkg/session/session_test.go	Removed RequireStack from command/session options; moved ProviderID from top-level SessionLoaderOptions into GetStackOpts; newCommandSession no longer gates on RequireStack; loadStack now propagates stack manager errors directly.
Stacks Manager src/pkg/stacks/manager.go, src/pkg/stacks/manager_test.go	Added ProviderID to GetStackOpts, removed RequireStack; GetStack now prefers provider-driven selection, then interactive selection, then default/fallback; whence/fallback messaging and default-stack error paths adjusted.
CLI Commands src/cmd/cli/command/compose.go, src/cmd/cli/command/cd.go, src/cmd/cli/command/config.go, src/cmd/cli/command/whoami.go	Removed explicit RequireStack assignments; replaced some direct session creation with session-loader flow that uses nested GetStackOpts; stack-manager creation failures logged non-fatally and caller proceeds when appropriate; provider capture added in whoami.
Client helpers & deprecations src/pkg/cli/client/projectName.go, src/pkg/cli/client/provider.go	Added deprecation comments for project-name fallback APIs; no signature changes.

Sequence Diagram

sequenceDiagram
    participant Cmd as CLI Command
    participant Loader as Session Loader
    participant SM as Stack Manager
    participant Provider as Provider

    Cmd->>Loader: Build SessionLoaderOptions (GetStackOpts.ProviderID)
    Loader->>SM: Request GetStack(ctx, GetStackOpts)
    alt ProviderID present (non-auto)
        SM->>Provider: Resolve provider-specific stack
        Provider-->>SM: Return stack (whence: provider)
    else Interactive selected
        SM->>Cmd: Prompt for stack selection
        Cmd-->>SM: User selection
    else Default / fallback
        SM-->>SM: Retrieve default stack or fallback local stack
    end
    SM-->>Loader: Return resolved stack
    Loader-->>Cmd: Return session with resolved stack (or error propagated)

Loading

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• Lio/stacks #1860: Directly modifies stack/session handling and GetStack/GetStackOpts APIs in parallel.
• Lio/fix default stack #1820: Related changes to SessionLoaderOptions and stack-loading codepaths.
• Onboard users to stacks during deployment #1700: Overlaps with compose/stack handling and RequireStack/creation behavior adjustments.

Suggested reviewers

• raphaeltm

Poem

🐇 I nibble at code, tidy and neat,
I tuck ProviderID into a nested seat.
RequireStack hops away, light and small,
Stack selection dances, answering the call.
Hooray for sessions that handle it all! 🎉

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 10.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: allowing the --provider flag to override stack selection behavior, which aligns with the core objective of the PR.

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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: 2

🤖 Fix all issues with AI agents

In @.vscode/launch.json:
- Around line 12-19: The "args" array in the launch.json configuration contains
a trailing comma after the commented lines which makes the JSON invalid; open
the "args" array for the launch configuration, remove the trailing comma after
the last active entry ("whoami") or uncomment/add at least one real argument so
the array ends without a dangling comma, then save to ensure the JSONC/JSON
parser no longer errors on the "args" array.

In `@src/cmd/cli/command/config.go`:
- Around line 83-85: Remove the redundant/unreachable error check for the
variable err in the function where the earlier if err != nil { return err }
already returns; specifically delete the second occurrence of "if err != nil {
return err }" (the dead-code check referencing err) so only the first error
handling remains and no duplicate return check is left in the config command
implementation (look for the err variable and the duplicate if err != nil {
return err } inside the function handling config in config.go).

[coderabbitai]

Actionable comments posted: 1

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (2)

src/cmd/cli/command/session.go (1)

34-38: Verify deploy commands don't silently proceed without a stack manager.

Errors from newStackManagerForLoader are logged and ignored (lines 36–38). When the stack manager fails, LoadSession falls back to using the default "beta" stack instead of failing. This allows deploy commands like compose up to proceed even when .defang is missing or corrupt, silently using a fallback stack. If stack-based configuration is required for correct deployment behavior, this silent fallback undermines that requirement and should either fail or be made explicit to the user.

src/pkg/session/session.go (1)

70-76: Normalize ProviderID to ProviderDefang when no stack manager is available.

When sl.sm is nil, loadStack returns sl.opts.ProviderID directly. If unset (empty string) or "auto", this represents an unresolved provider value. The codebase elsewhere treats both empty string and ProviderAuto as requiring resolution (see wizard.go:45, manager.go:216). While cli.NewProvider correctly defaults to PlaygroundProvider for these cases, it's clearer to explicitly normalize to ProviderDefang in this code path to match the intended default behavior and improve code clarity.

🛠️ Suggested fix

 if sl.sm == nil {
+	provider := sl.opts.ProviderID
+	if provider == "" || provider == client.ProviderAuto {
+		provider = client.ProviderDefang
+	}
 	return &stacks.Parameters{
 		Name:     stacks.DefaultBeta,
-		Provider: sl.opts.ProviderID,
+		Provider: provider,
 	}, "no stack manager available", nil
 }

🤖 Fix all issues with AI agents

In `@src/pkg/stacks/manager.go`:
- Around line 203-248: GetStack currently silently returns a hardcoded fallback
stack when no stack/provider/default exists; add an explicit opt-out in
GetStackOpts (e.g., RequireStack or DisallowFallback bool) and change GetStack
to honor it: when the opt is set and no explicit Stack/Provider and
sl.getDefaultStack returns ErrDefaultStackNotSet, return that error instead of
creating the DefaultBeta fallback; update callers that need strict behavior
(e.g., compose up) to pass the new flag so they can fail fast, and leave
interactive branches (getStackInteractively) unchanged.

♻️ Duplicate comments (1)

src/cmd/cli/command/config.go (1)

78-84: Remove unreachable duplicate error check.

err is already handled after AccountInfo; the second check is unreachable.

🔧 Cleanup

 	_, err = session.Provider.AccountInfo(ctx)
 	if err != nil {
 		return fmt.Errorf("failed to get account info from provider %q: %w", session.Stack.Provider, err)
 	}
-	if err != nil {
-		return err
-	}

🧹 Nitpick comments (1)

src/pkg/stacks/manager_test.go (1)

650-825: Add coverage for provider/default/fallback stack resolution.

With RequireStack removed and provider-first/fallback logic moved into GetStack, TestGetStack no longer exercises:

• ProviderID-based selection (flag vs env),
• Default stack resolution, and
• Fallback stack behavior when no default is set.

Consider adding table cases to lock in these new paths and prevent regressions around the “fallback allowed only for non-deploy” objective.

[coderabbitai]

Actionable comments posted: 0

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

src/cmd/cli/command/config.go (1)

34-81: Remove early return on stack manager failure to allow provider-based fallback.

At line 69-71, returning early on newStackManagerForLoader error blocks the provider-based fallback. The session loader's loadStack method explicitly handles nil stack managers (returning a default stack via the provider), but your code prevents reaching that fallback by erroring out. Follow the pattern used in session.go line 35-37: log the error but continue with the nil stack manager.