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Fix march not to wipe out concurrent updates

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March code reads the land units into a land unit list, and writes them
back when it changes them, e.g. when a land unit stops.  If a land
unit changes in the land unit file while it is in such a land unit
list, the copy in the land unit list becomes stale, and must not be
used.

To that end, do_unit_move() calls lnd_mar() after prompting for path
or destination.  lnd_mar() re-reads all the land units.
Unfortunately, it still writes back stale copies in certain
circumstances.  Known ways to trigger such writes:

* Deity loads land unit onto a ship or land unit

* Land unit's crew killed just right, e.g. by collateral damage from
  interdiction, followed by additional updates, such as shell fire
  damage

* Sector no longer owned or allied, e.g. allied sector captured by an
  enemy (own sector would kill or retreat the land unit)

Writing a stale copy wipes out the updates that made the copy stale,
and triggers a seqno mismatch oops.  For instance, damage that follows
killing of all crew by collateral damage from interdiction is wiped
out.  If no damage follows, we still get a generation oops.
This commit is contained in:
Markus Armbruster 2012-05-18 16:29:19 +02:00
parent a694e49343
commit 0dd59211aa
1 changed files with 17 additions and 17 deletions
Download patch file Download diff file Expand all files Collapse all files

34
src/lib/subs/lndsub.c
View file

@ -460,8 +460,8 @@ lnd_mar(struct emp_qelem *list, double *minmobp, double *maxmobp,
struct emp_qelem *qp;
struct emp_qelem *next;
struct ulist *llp;
struct lndstr *lp;
struct sctstr sect;
struct lndstr land;
coord allx;
coord ally;
int first = 1;
@ -473,54 +473,54 @@ lnd_mar(struct emp_qelem *list, double *minmobp, double *maxmobp,
for (qp = list->q_back; qp != list; qp = next) {
next = qp->q_back;
llp = (struct ulist *)qp;
getland(llp->unit.land.lnd_uid, &land);
if (land.lnd_own != actor) {
lp = &llp->unit.land;
getland(lp->lnd_uid, lp);
if (lp->lnd_own != actor) {
mpr(actor, "%s was disbanded at %s\n",
prland(&land), xyas(land.lnd_x, land.lnd_y, actor));
prland(lp), xyas(lp->lnd_x, lp->lnd_y, actor));
emp_remque((struct emp_qelem *)llp);
free(llp);
continue;
}
if (land.lnd_ship >= 0) {
if (lp->lnd_ship >= 0) {
lnd_stays(actor, "is on a ship", llp);
continue;
}
if (land.lnd_land >= 0) {
if (lp->lnd_land >= 0) {
lnd_stays(actor, "is on a unit", llp);
continue;
}
if (!getsect(land.lnd_x, land.lnd_y, &sect)) {
if (!getsect(lp->lnd_x, lp->lnd_y, &sect)) {
lnd_stays(actor, "was sucked into the sky by a strange looking spaceland", llp); /* heh -KHS */
continue;
}
if (!(lchr[(int)llp->unit.land.lnd_type].l_flags & L_SPY) &&
!(lchr[(int)llp->unit.land.lnd_type].l_flags & L_TRAIN) &&
llp->unit.land.lnd_item[I_MILIT] == 0) {
if (!(lchr[lp->lnd_type].l_flags & L_SPY) &&
!(lchr[lp->lnd_type].l_flags & L_TRAIN) &&
lp->lnd_item[I_MILIT] == 0) {
lnd_stays(actor, "has no mil on it to guide it", llp);
continue;
}
if (relations_with(sect.sct_own, actor) != ALLIED &&
!(lchr[(int)llp->unit.land.lnd_type].l_flags & L_SPY) &&
!(lchr[lp->lnd_type].l_flags & L_SPY) &&
sect.sct_own) {
sprintf(mess, "has been kidnapped by %s", cname(sect.sct_own));
lnd_stays(actor, mess, llp);
continue;
}
if (first) {
allx = land.lnd_x;
ally = land.lnd_y;
allx = lp->lnd_x;
ally = lp->lnd_y;
first = 0;
}
if (land.lnd_x != allx || land.lnd_y != ally)
if (lp->lnd_x != allx || lp->lnd_y != ally)
*togetherp = 0;
if (land.lnd_mobil + 1 < (int)llp->mobil) {
llp->mobil = land.lnd_mobil;
if (lp->lnd_mobil + 1 < (int)llp->mobil) {
llp->mobil = lp->lnd_mobil;
}
if (llp->mobil < *minmobp)
*minmobp = llp->mobil;
if (llp->mobil > *maxmobp)
*maxmobp = llp->mobil;
llp->unit.land = land;
}
}