Address PR review: prune short-circuit, dry-run sync, fetch-mainline guard

- applyRepoFetchPrune: skip git config read when CLI sets prune; warn and
  fall back on ReadRainFetchPrune errors
- Reject --fetch-mainline with full-sync triggers; add test
- runDryRun: show fetch --prune resolution for --sync path too
- Fix Upsert for-loop indentation (gofmt)
- UAT scenario 7 echo matches prune-opt-in default
- CLAUDE/README: prune precedence and --fetch-mainline note
- Replace misleading frozen label (fetch --all)

Co-authored-by: Ben Schellenberger <bschellenberger2600@users.noreply.github.com>

Author: cursoragent

CLAUDE.md

@@ -2,7 +2,16 @@
 
 ## Project Overview
 
-`git-rain` is a standalone Go CLI for pulling remote state back down — the reverse of `git-fire`. Operating modes, lightest to heaviest: **(1)** default `git fetch --all` per repo (`--prune` opt-in via `--prune`/`--no-prune`, `global.fetch_prune`, registry `fetch_prune`, or `git config --local rain.fetchprune`); **(2)** `--fetch-mainline`; **(3)** `--sync` + `branch_mode`; **(4)** `--risky` on the sync path. Extracted from the `git-fire` codebase and promoted to a first-class tool.
+`git-rain` is a standalone Go CLI for pulling remote state back down — the reverse of `git-fire`.
+
+Operating modes, lightest to heaviest:
+
+1. **Default** — `git fetch --all` per repo. `--prune` is opt-in. Precedence per repo: CLI (`--prune` / `--no-prune`) → local `git config rain.fetchprune` → registry `fetch_prune` → global `fetch_prune`.
+2. **`--fetch-mainline`** — targeted fetches for mainline branches only (incompatible with `--sync` / full-sync triggers; CLI returns an error if combined).
+3. **`--sync` + `branch_mode`** — hydrate local branches from remotes.
+4. **`--risky`** — on the sync path only; allows hard reset to upstream after backup refs.
+
+Extracted from the `git-fire` codebase and promoted to a first-class tool.
 
 Module: `github.com/git-rain/git-rain`
 Go version: 1.24.2

README.md

@@ -20,7 +20,7 @@ git-rain  →  fetch all remotes by default, or hydrate locals with --sync
 
 `git-rain` discovers git repositories under your scan path (and known registry entries). **Default:** `git fetch --all` per repo (no `--prune` unless you opt in) so **remote-tracking refs** update without moving local branches. **Lighter fetch:** `--fetch-mainline`. **Local updates:** `--sync` with `--branch-mode` / config. **Destructive realignment:** `--risky` on the sync path only.
 
-> **Warning: `--prune` is opt-in.** Passing `--prune` on `git fetch` deletes **stale remote-tracking branch refs** (for example `refs/remotes/origin/old-feature` after that branch was removed on the server). That is usually what you want for a tidy clone, but it **removes those ref names locally** until the next fetch brings them back if the branch reappears. Enable pruning only when you intend it: **`--prune`** / **`--no-prune`** for this run, **`global.fetch_prune`** in config, **`fetch_prune`** on a registry entry, or per-repo **`git config --local --bool rain.fetchprune true`**. Precedence for a given repo is: **CLI** → **repo `rain.fetchprune`** → **registry `fetch_prune`** → **global `fetch_prune`**.
+> **Warning: `--prune` is opt-in.** Passing `--prune` on `git fetch` deletes **stale remote-tracking branch refs** (for example `refs/remotes/origin/old-feature` after that branch was removed on the server). That is usually what you want for a tidy clone, but it **removes those ref names locally** until the next fetch brings them back if the branch reappears. Enable pruning only when you intend it, in this order of override: **`--prune`** / **`--no-prune`** for this run, per-repo **`git config --local --bool rain.fetchprune`**, **`fetch_prune`** on a registry entry, or **`global.fetch_prune`** in config. Effective precedence for each repo is: **CLI** → **`rain.fetchprune`** → **registry `fetch_prune`** → **global `fetch_prune`**.
 
 Invocation note: `git-rain` and `git rain` are equivalent when `git-rain` is on your PATH.
 
@@ -223,7 +223,7 @@ git-rain --init
 | `--dry-run` | Show what would run without making changes |
 | `--rain` | Interactive TUI repo picker before running (like `git-fire --fire`) |
 | `--sync` | Update local branches from remotes (after `git fetch --all`; default run does not sync locals) |
-| `--fetch-mainline` | Mainline-only remote `git fetch` per remote instead of default `git fetch --all` |
+| `--fetch-mainline` | Mainline-only remote `git fetch` per remote instead of default `git fetch --all` (not with `--sync` or other full-sync triggers) |
 | `--branch-mode` | With `--sync`: `mainline`, `checked-out`, `all-local`, or `all-branches` (overrides config for this run) |
 | `--prune` | Pass `--prune` on fetch for this run (highest precedence; cannot combine with `--no-prune`) |
 | `--no-prune` | Never pass `--prune` on fetch for this run (overrides `--prune`, config, registry, and `rain.fetchprune`) |

cmd/prune_resolve_test.go

@@ -168,6 +168,17 @@ func TestApplyRepoFetchPrune_NoPruneOverridesGitTrue(t *testing.T) {
 	}
 }
 
+func TestRunRain_FetchMainlineWithSyncErrors(t *testing.T) {
+	tmpHome := t.TempDir()
+	setTestUserDirs(t, tmpHome)
+	resetFlags()
+	rainFetchMainline = true
+	rainSync = true
+	if err := runRain(rootCmd, []string{}); err == nil {
+		t.Fatal("expected error when --fetch-mainline and --sync both set")
+	}
+}
+
 func TestRunRain_PruneAndNoPruneTogetherErrors(t *testing.T) {
 	tmpHome := t.TempDir()
 	setTestUserDirs(t, tmpHome)

cmd/root.go

@@ -149,6 +149,9 @@ func runRain(_ *cobra.Command, _ []string) error {
 	}
 
 	fullSync := computeFullSync(rainSync, rainRisky, cfg.Global.RiskyMode, rainBranchMode, cfg.Global.BranchMode)
+	if fullSync && rainFetchMainline {
+		return fmt.Errorf("--fetch-mainline only applies to fetch-only runs; remove --sync, --risky, non-mainline --branch-mode, or risky_mode in config")
+	}
 	if fullSync && rainOpts.BranchMode == git.BranchSyncAllBranches {
 		fmt.Println("⚠️  all-branches mode: remote branches will be created locally — this can produce many local branches")
 	}
@@ -266,7 +269,7 @@ func runRain(_ *cobra.Command, _ []string) error {
 
 		if !fullSync && !rainFetchMainline {
 			if fetchErr := fetchOnly(repo.Path, repoOpts); fetchErr != nil {
-				fmt.Printf("    ❄  (all branches): %s\n\n",
+				fmt.Printf("    ❄  (fetch --all): %s\n\n",
 					safety.SanitizeText(fetchFailureMessage(fetchErr.Error())))
 				totalFrozen++
 				continue
@@ -614,7 +617,7 @@ func runRainOnRepos(reg *registry.Registry, repos []git.Repository, opts git.Rai
 
 		if !fullSync && !rainFetchMainline {
 			if fetchErr := fetchOnly(repo.Path, repoOpts); fetchErr != nil {
-				fmt.Printf("    ❄  (all branches): %s\n\n",
+				fmt.Printf("    ❄  (fetch --all): %s\n\n",
 					safety.SanitizeText(fetchFailureMessage(fetchErr.Error())))
 				totalFrozen++
 				continue
@@ -684,6 +687,12 @@ func runRainOnRepos(reg *registry.Registry, repos []git.Repository, opts git.Rai
 
 func applyRepoFetchPrune(repoPath string, base git.RainOptions, absPath string, reg *registry.Registry) (git.RainOptions, error) {
 	opt := base
+	cliSet := rainPrune || rainNoPrune
+	cliVal := rainPrune && !rainNoPrune
+	if cliSet {
+		opt.FetchPrune = git.ResolveFetchPrune(cliSet, cliVal, false, false, nil, base.FetchPrune)
+		return opt, nil
+	}
 	var regPrune *bool
 	if reg != nil {
 		if e := reg.FindByPath(absPath); e != nil {
@@ -692,10 +701,9 @@ func applyRepoFetchPrune(repoPath string, base git.RainOptions, absPath string,
 	}
 	gitSet, gitVal, err := git.ReadRainFetchPrune(repoPath)
 	if err != nil {
-		return opt, err
+		fmt.Fprintf(os.Stderr, "warning: reading %s in %s: %v\n", git.RainFetchPruneConfigKey, repoPath, err)
+		gitSet, gitVal = false, false
 	}
-	cliSet := rainPrune || rainNoPrune
-	cliVal := rainPrune && !rainNoPrune
 	opt.FetchPrune = git.ResolveFetchPrune(cliSet, cliVal, gitSet, gitVal, regPrune, base.FetchPrune)
 	return opt, nil
 }

scripts/uat.sh

@@ -269,7 +269,7 @@ echo "── scenario 6: risky mode resets local-ahead branch"
 
 # ── SCENARIO 7: default full fetch (no local branch moves) ─────────────────
 echo
-echo "── scenario 7: default git fetch --all --prune"
+echo "── scenario 7: default git fetch --all (prune opt-in)"
 {
   scenario_begin s7
   d="$SCENARIO_D"