Only examine first 512 log line bytes for warnings detection

Fixes

1 files changed, 7 insertions, 1 deletions

diff --git a/bbot/worker.cxx b/bbot/worker.cxx
index a0e2ad7..81d9a50 100644
--- a/bbot/worker.cxx
+++ b/bbot/worker.cxx
@@ -116,7 +116,13 @@ run_bpkg (tracer& t,
         {
           for (const auto& re: warn_detect)
           {
-            if (regex_search (l, re))
+            // Only examine the first 512 bytes. Long lines (e.g., linker
+            // command lines) could trigger implementation-specific limitations
+            // (like stack overflow). Plus, it is a performance concern.
+            //
+            if (regex_search (l.begin (),
+                              l.size () < 512 ? l.end () : l.begin () + 512,
+                              re))
             {
               r = result_status::warning;
               break;