Milestones 4 and 5: project layer, review gate and serial merge, all measured

bin/review

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+"""Review one task's diff and print the verdict. Merge nothing.
+
+    bin/review AUD-164            # review and print
+    bin/review AUD-164 --post     # also write the verdict on the task
+
+This is the same review `bin/merge` runs, on its own, so a person can look
+before the merge is attempted. Exit 0 means nothing blocking was found; exit 5
+means the review refused; exit 7 means there is no worktree to look at.
+"""
+
+import os
+import sys
+
+sys.path.insert(0, os.path.join(os.path.dirname(os.path.abspath(__file__)), "lib"))
+import harness as h  # noqa: E402
+
+
+def main():
+    args = [a for a in sys.argv[1:] if not a.startswith("--")]
+    post = "--post" in sys.argv
+    if len(args) != 1:
+        h.say("usage: bin/review <task> [--post]")
+        return 2
+
+    issue = h.find_issue(args[0])
+    ref = issue["identifier"]
+    worktree, branch, base = h.worktree_of(issue)
+
+    h.say("%s %s" % (ref, issue["title"]))
+    h.say("  worktree %s" % worktree)
+    h.say("  range    %s...HEAD (%s)" % (base, branch))
+
+    report = h.ocr_review(worktree, base, "HEAD")
+    status = report.get("status")
+    reviewed = (report.get("summary") or {}).get("files_reviewed", 0)
+    comments = report.get("comments") or []
+
+    if status == "skipped" and reviewed == 0:
+        h.say("  nothing reviewable in the change (0 files)")
+        if post:
+            h.verdict(issue, "## Review: nothing to review\n\nocr selected 0 files "
+                      "from the change, so nothing was checked.")
+        return 0
+    if status != "complete":
+        h.say("  review could not complete: %s" % (report.get("message") or status))
+        if post:
+            h.verdict(issue, "## Review could not run\n\nocr returned `%s` — %s"
+                      % (status, report.get("message") or "no reason given"))
+        return 5
+
+    blocking = h.blocking_findings(report)
+    for c in comments:
+        marker = "BLOCKS" if c in blocking else "note  "
+        h.say("  %s %s" % (marker, h.describe(c)))
+
+    verdict = ("%d comment(s); %d blocking" % (len(comments), len(blocking)))
+    h.say("  %s" % verdict)
+
+    if post:
+        body = "## Review\n\n%s" % (verdict)
+        if blocking:
+            body += "\n\nBlocking:\n" + "\n".join(h.describe(c) for c in blocking)
+        h.verdict(issue, body)
+
+    return 5 if blocking else 0
+
+
+if __name__ == "__main__":
+    h.main_guard(main)