remake: no --follow-strict-remakes; a strict remake failing says who

A strict remake takes a majority of members whose --strict-keys take
its manifest's signer: no node votes for one without, so
--follow-strict-remakes (1173) goes. A node that doesn't vote still
switches once the others commit, as with any remake.

So that an operator can tell why one fails: a strict remake aborted
for want of a majority (the voting period over, or a majority out of
reach) says in its reason (GET /admin/remakes/{id}, and the
coordinator's log) which members didn't vote, and that a member votes
for one only with its manifest signed by a key of its --strict-keys.
Each of those logs why itself (`Not voting for a strict remake`).

The sim a_strict_remake_too_few_take: only a takes the manifest; the
remake aborts, naming b and c.

1 files changed, 41 insertions, 2 deletions

diff --git a/src/remake/coordinator.rs b/src/remake/coordinator.rs
index 314cd87..0d7a434 100644
--- a/src/remake/coordinator.rs
+++ b/src/remake/coordinator.rs
@@ -138,7 +138,10 @@ async fn step<H: Host>(host: &H, id: &str) -> Result<bool, StoreError> {
         decide_abort(
             host,
             id,
-            format!("no majority in the voting period: {tally}"),
+            format!(
+                "no majority in the voting period: {tally}{}",
+                strict_hint(id, &record, &register)
+            ),
         )
         .await?;
         return Ok(true);
@@ -149,12 +152,48 @@ async fn step<H: Host>(host: &H, id: &str) -> Result<bool, StoreError> {
         return Ok(true);
     }
     if tally.out_of_reach() {
-        decide_abort(host, id, format!("a majority is out of reach: {tally}")).await?;
+        decide_abort(
+            host,
+            id,
+            format!(
+                "a majority is out of reach: {tally}{}",
+                strict_hint(id, &record, &register)
+            ),
+        )
+        .await?;
         return Ok(true);
     }
     Ok(false)
 }
 
+/// For a strict remake `id` without a majority: who didn't vote, and why they may not
+/// have (`vote::strict_taken`), for its operator to tell from the reason. Nothing for
+/// another kind, or if all voted.
+fn strict_hint(id: &str, record: &Record, register: &records::Register) -> String {
+    if record.proposal.kind != "strict" {
+        return String::new();
+    }
+    let silent: Vec<&str> = record
+        .proposal
+        .electorate
+        .iter()
+        .filter(|member| {
+            register
+                .get(member.as_str())
+                .is_none_or(|votes| !votes.iter().any(|vote| vote.remake == id))
+        })
+        .map(String::as_str)
+        .collect();
+    if silent.is_empty() {
+        return String::new();
+    }
+    format!(
+        "; a strict remake, not voted for by {}: a member votes for one only with its \
+         manifest signed by a key of its --strict-keys (or it was away)",
+        silent.join(", ")
+    )
+}
+
 /// Why remake `id` must be aborted whatever its votes, if it must.
 fn obstacle(id: &str, record: &Record, all: &[(String, Record)]) -> Option<String> {
     if let Some(request) = &record.abort_requested {