Merge pull request #5 from git-fire/feat/gmt-watch-rewrite-scenarios

git: add bounded rewrite scenario orchestration

Author: bschellenberger2600

README.md

@@ -22,6 +22,36 @@ go vet ./...
 go test -race -count=1 ./...
 ```
 
+## Rewrite Orchestration (git-fcuk flow)
+
+The `git` package now includes bounded multi-pass rewrite orchestration via
+`RunRewriteScenario`, designed for flows that must:
+
+1. Detect whether intervention is needed.
+2. Intervene (run one rewrite pass).
+3. Verify the repo is clean.
+4. Rerun from detect until clean or attempts are exhausted.
+
+Use it for safety-first rewrite loops where you need deterministic stop
+conditions and pass-by-pass telemetry (`RewriteScenarioResult.Passes`).
+
+### Validate locally
+
+```bash
+# Targeted rewrite orchestration tests
+go test -count=1 ./git -run RunRewriteScenario
+
+# Full module sanity
+go test -count=1 ./...
+```
+
+Expected outcome:
+
+- Targeted run: `ok   github.com/git-fire/git-harness/git ...`
+- Full run: all packages return `ok` with no failing tests
+- If a rewrite loop never reaches clean within `MaxAttempts`, callers receive
+  `ErrRewriteAttemptsExceeded`
+
 ## Stability
 
 `v0.x` releases may change APIs; pin a minor or patch version in consumers.

git/rewrite_scenario.go

@@ -0,0 +1,137 @@
+package git
+
+import (
+	"context"
+	"errors"
+	"fmt"
+)
+
+// ErrRewriteAttemptsExceeded indicates a rewrite run remained dirty after all
+// configured attempts were used.
+var ErrRewriteAttemptsExceeded = errors.New("rewrite scenario exceeded maximum attempts")
+
+// RewriteScenarioOptions configures detect -> intervene -> verify orchestration.
+//
+// The flow is:
+//  1. Detect whether rewrite intervention is required.
+//  2. Intervene when required.
+//  3. Verify whether the repo is now clean.
+//  4. Repeat until clean or attempts are exhausted.
+type RewriteScenarioOptions struct {
+	// MaxAttempts bounds total detect passes. Must be >= 1.
+	MaxAttempts int
+
+	// Detect reports whether intervention is needed for the attempt.
+	// Return true when the repository still needs rewrite intervention.
+	Detect func(ctx context.Context, attempt int) (needsIntervention bool, err error)
+
+	// Intervene performs one rewrite intervention pass for the attempt.
+	Intervene func(ctx context.Context, attempt int) error
+
+	// Verify checks whether the repository is clean after intervention.
+	// Return true when no further rewrite intervention is needed.
+	Verify func(ctx context.Context, attempt int) (clean bool, err error)
+}
+
+// RewriteAttempt captures one detect pass in the orchestration loop.
+type RewriteAttempt struct {
+	Attempt           int  // 1-based pass number
+	NeedsIntervention bool // Detect outcome
+	Intervened        bool // Whether Intervene ran
+	CleanAfterVerify  bool // Verify outcome when Intervene ran
+}
+
+// RewriteScenarioResult captures pass-by-pass outcomes.
+type RewriteScenarioResult struct {
+	Clean    bool
+	Attempts int
+	Passes   []RewriteAttempt
+}
+
+// RunRewriteScenario executes bounded detect -> intervene -> verify passes until
+// the repository is clean or attempts are exhausted.
+func RunRewriteScenario(ctx context.Context, opts RewriteScenarioOptions) (RewriteScenarioResult, error) {
+	result := RewriteScenarioResult{}
+
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	if opts.MaxAttempts < 1 {
+		return result, fmt.Errorf("max attempts must be >= 1")
+	}
+	if opts.Detect == nil {
+		return result, fmt.Errorf("detect callback is required")
+	}
+	if opts.Intervene == nil {
+		return result, fmt.Errorf("intervene callback is required")
+	}
+	if opts.Verify == nil {
+		return result, fmt.Errorf("verify callback is required")
+	}
+
+	for attempt := 1; attempt <= opts.MaxAttempts; attempt++ {
+		if err := ctx.Err(); err != nil {
+			result.Attempts = attempt - 1
+			return result, fmt.Errorf("rewrite scenario cancelled before attempt %d: %w", attempt, err)
+		}
+
+		pass := RewriteAttempt{Attempt: attempt}
+
+		needsIntervention, err := opts.Detect(ctx, attempt)
+		if err != nil {
+			result.Attempts = attempt
+			result.Passes = append(result.Passes, pass)
+			return result, fmt.Errorf("detect failed on attempt %d: %w", attempt, err)
+		}
+		pass.NeedsIntervention = needsIntervention
+
+		if !needsIntervention {
+			result.Attempts = attempt
+			result.Clean = true
+			result.Passes = append(result.Passes, pass)
+			return result, nil
+		}
+
+		if err := ctx.Err(); err != nil {
+			result.Attempts = attempt
+			result.Passes = append(result.Passes, pass)
+			return result, fmt.Errorf("rewrite scenario cancelled before intervene on attempt %d: %w", attempt, err)
+		}
+
+		if err := opts.Intervene(ctx, attempt); err != nil {
+			result.Attempts = attempt
+			result.Passes = append(result.Passes, pass)
+			return result, fmt.Errorf("intervene failed on attempt %d: %w", attempt, err)
+		}
+		pass.Intervened = true
+
+		if err := ctx.Err(); err != nil {
+			result.Attempts = attempt
+			result.Passes = append(result.Passes, pass)
+			return result, fmt.Errorf("rewrite scenario cancelled before verify on attempt %d: %w", attempt, err)
+		}
+
+		clean, err := opts.Verify(ctx, attempt)
+		if err != nil {
+			result.Attempts = attempt
+			result.Passes = append(result.Passes, pass)
+			return result, fmt.Errorf("verify failed on attempt %d: %w", attempt, err)
+		}
+		pass.CleanAfterVerify = clean
+		result.Passes = append(result.Passes, pass)
+
+		if clean {
+			result.Attempts = attempt
+			result.Clean = true
+			return result, nil
+		}
+
+		if err := ctx.Err(); err != nil {
+			result.Attempts = attempt
+			return result, fmt.Errorf("rewrite scenario cancelled after verify on attempt %d: %w", attempt, err)
+		}
+	}
+
+	result.Attempts = opts.MaxAttempts
+	return result, fmt.Errorf("%w: attempts=%d", ErrRewriteAttemptsExceeded, opts.MaxAttempts)
+}