daemon: fix SIGUSR2 upgrade with -W0 (no workers)

[public-inbox.git] / HACKING

diff --git a/HACKING b/HACKING
index 666d504e7336b61ef7d26f559e5b192c56fbd9de..5e02302c64c0941516a3a720a7f414fc232bb4d3 100644 (file)
--- a/HACKING
+++ b/HACKING
@@ -32,7 +32,7 @@ may be too difficult to upgrade due to resource demands.
 Only depend on Free Software packages which exist in the "main"
 section of Debian "stable" distribution.  That is Debian 9.x
 ("stretch") as of this writing, but "oldstable" (8.x, "jessie")
-remains supported for v1 repositories.
+remains supported for v1 inboxes.
 
 In general, we favor mature and well-tested old things rather than
 the shiny new.
@@ -43,6 +43,11 @@ distribute and verify.  public-inbox itself will only be implemented
 in scripting languages (currently Perl 5) and optional JIT-compiled C
 (via Inline::C)
 
+Do not recurse on user-supplied data.  Neither Perl or C handle
+deep recursion gracefully.  See lib/PublicInbox/SearchThread.pm
+and lib/PublicInbox/MsgIter.pm for examples of non-recursive
+alternatives to previously-recursive algorithms.
+
 Performance should be reasonably good for server administrators, too,
 and we will sacrifice features to achieve predictable performance.
 Encouraging folks to self-host will be easier with lower hardware