# Task B2 Report: Registry Validator Script

## Status
DONE — commit `e3e219e`: feat(patches): add registry validator script

## File created
`local/validate-patches.R` — written verbatim from the brief.

## Step 2: Success case
```
$ Rscript local/validate-patches.R; echo "exit=$?"
Patch registry OK (1 entrie(s)).
exit=0
```
Matches expected output exactly.

## Step 3: Failure case
```
$ cp local/patches/registry.json /tmp/reg.bak
$ Rscript -e 'writeLines("[{\"package\":\"X\"}]", "local/patches/registry.json")'
$ Rscript local/validate-patches.R; echo "exit=$?"
Error in vapply(reg, function(e) { : values must be length 1,
 but FUN(X[[1]]) result is length 0
Execution halted
exit=1
$ cp /tmp/reg.bak local/patches/registry.json
```

Exit code is 1 as required.
Note: the broken entry (missing `versions`) causes the `vapply` call to crash with an R runtime error before reaching the `validation FAILED` print path.
The error message is different from the brief's expected text, but the exit code contract (exit=1) is met.
This is a behaviour of the verbatim script from the brief — not a deviation.

## Registry restore verification
After `cp /tmp/reg.bak local/patches/registry.json`, `git status` shows no diff on `local/patches/registry.json` — it is byte-identical to the original.

## Git status before commit
Only `local/validate-patches.R` was staged; `.superpowers/` remained untracked and was not committed.

## Concerns
The `vapply` call in the ambiguous-overlap check will crash (rather than report a clean validation error) when an entry is missing its `versions` field.
The missing-field loop catches the schema error and populates `errs`, but the script reaches the `vapply` before printing those errors.
Downstream tasks (B3/B4) may want to guard the `vapply` with a length/NULL check so the FAILED message is always printed cleanly.
This was not changed here — the task required verbatim implementation of the brief.

---

## Fix: Null-safe key construction (commit `7e382c7`)

### What changed
In `local/validate-patches.R`, the `keys <- vapply(...)` block now uses `%||%` (base R 4.5.3) to substitute `"?"` for any NULL `e$package` or `e$versions`:

```r
keys <- vapply(reg, function(e) {
  sprintf(
    "%s|%s|%s",
    e$package %||% "?",
    paste(sort(as.character(unlist(e$platforms))), collapse = ","),
    e$versions %||% "?"
  )
}, character(1L))
```

No other code changed (validation loop, error-print block, exit codes, messages all unchanged).

### Verify: good registry (exit 0)
```
$ Rscript local/validate-patches.R; echo "exit=$?"
Patch registry OK (1 entrie(s)).
exit=0
```

### Verify: malformed registry (exit 1, no stacktrace)
```
$ cp local/patches/registry.json /tmp/reg.bak
$ Rscript -e 'writeLines("[{\"package\":\"X\"}]", "local/patches/registry.json")'
$ Rscript local/validate-patches.R; echo "exit=$?"
Patch registry validation FAILED:
  - entry 1 (X): missing versions, platforms, reason
exit=1
$ cp /tmp/reg.bak local/patches/registry.json
registry restored
```
No R `Error in ...` / `Execution halted` stacktrace. Clean `validation FAILED` message with all collected errors printed before exit.