refactor: Use compact +N/-N/~N script change format (#19)

Ref #18

Author: TsekNet

README.md

@@ -26,7 +26,7 @@ Run in CI **before** `fleetctl gitops --dry-run`. fleet-plan shows *what* change
 | Team-scoped | Diff one team, multiple teams, or all teams at once |
 | CI integration | `--git` auto-detects GitLab/GitHub, resolves changed files, posts MR/PR comment |
 | Multi-env merge | `--base` + `--env` merges config overlays in-memory (no `yq` needed) |
-| Script diffing | Line-count diffs for team scripts (+N/-N) |
+| Script diffing | Line-count diffs for team scripts (`+N/-N`, `~N` for single-line) |
 | Label validation | Cross-references labels against Fleet, shows host counts |
 | Multiple formats | Terminal (colored), JSON, Markdown |
 | Read-only | GET requests only, never mutates Fleet |

docs/Architecture.md

@@ -98,7 +98,7 @@ Compares `FleetState` (API) vs `ParsedRepo` (YAML). Produces `[]DiffResult` per
 | Fleet-maintained apps | `slug` | self_service |
 | App Store apps | `app_store_id` | self_service |
 | Profiles | PayloadDisplayName | add/delete only |
-| Scripts | filename | line count diff (+N/-N) |
+| Scripts | filename | line count diff (`+N/-N`, `~N` for single-line) |
 | Labels | `name` (cross-ref) | valid/missing with host counts |
 
 Whitespace is normalized before comparison to avoid false positives from YAML vs API newline differences. Per-field diffs are stored in `ResourceChange.Fields` for both added and modified resources.

internal/diff/differ.go

@@ -1205,13 +1205,15 @@ func getNestedValue(m map[string]any, key string) string {
 // ---------- Helpers ----------
 
 // scriptDiffSummary returns a human-readable summary of what changed between
-// two normalized script contents. For single-line changes it shows the line
-// number. For multi-line changes it shows insertion/deletion counts.
+// two normalized script contents. Uses a compact "+added/-deleted" format,
+// omitting zero counts. For single-line changes it includes the line number
+// (e.g. "+5", "-3", "~2").
 func scriptDiffSummary(old, new string) string {
 	oldLines := strings.Split(old, "\n")
 	newLines := strings.Split(new, "\n")
 
-	// Build a set of old lines for membership check
+	// Bag-of-lines: count lines present in new but not old (inserted)
+	// and lines present in old but not new (deleted).
 	oldSet := make(map[string]int)
 	for _, l := range oldLines {
 		oldSet[l]++
@@ -1221,7 +1223,6 @@ func scriptDiffSummary(old, new string) string {
 		newSet[l]++
 	}
 
-	// Count insertions (lines in new but not in old) and deletions (lines in old but not in new)
 	inserted := 0
 	for l, count := range newSet {
 		if diff := count - oldSet[l]; diff > 0 {
@@ -1236,7 +1237,7 @@ func scriptDiffSummary(old, new string) string {
 	}
 
 	if inserted+deleted == 1 {
-		// Find the single changed line and show its position
+		// Single change: find its line number.
 		maxLen := len(oldLines)
 		if len(newLines) > maxLen {
 			maxLen = len(newLines)
@@ -1250,18 +1251,27 @@ func scriptDiffSummary(old, new string) string {
 				n = newLines[i]
 			}
 			if o != n {
+				ln := i + 1
 				if o == "" {
-					return fmt.Sprintf("+Line %d", i+1)
+					return fmt.Sprintf("+%d", ln)
 				}
 				if n == "" {
-					return fmt.Sprintf("-Line %d", i+1)
+					return fmt.Sprintf("-%d", ln)
 				}
-				return fmt.Sprintf("~Line %d", i+1)
+				return fmt.Sprintf("~%d", ln)
 			}
 		}
 	}
 
-	return fmt.Sprintf("+%d lines, -%d lines", inserted, deleted)
+	// Compact format, omitting zero counts.
+	var parts []string
+	if inserted > 0 {
+		parts = append(parts, fmt.Sprintf("+%d", inserted))
+	}
+	if deleted > 0 {
+		parts = append(parts, fmt.Sprintf("-%d", deleted))
+	}
+	return strings.Join(parts, "/")
 }
 
 // normalizeScript normalizes a script for comparison: trims whitespace and

internal/output/markdown.go

@@ -199,7 +199,7 @@ func mdFieldDetails(fields map[string]diff.FieldDiff) string {
 	for _, name := range names {
 		fd := fields[name]
 		if fd.Old == "" && fd.New != "" {
-			// Summary-only field (e.g., script diff with +N/-N lines)
+			// Summary-only field (e.g., script diff with +N/-N format)
 			parts = append(parts, fmt.Sprintf("`%s`: %s", name, mdCodeSpan(fd.New)))
 		} else {
 			old, new := mdDiffContext(fd.Old, fd.New, mdMaxFieldLen)