From 0e86d6f5a10972ab8c97145cfe4812edb3048948 Mon Sep 17 00:00:00 2001
From: John Alanbrook <john@pockle.world>
Date: Fri, 20 Feb 2026 19:06:03 -0600
Subject: [PATCH] debug output on build

---
 build.cm | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/build.cm b/build.cm
index 176e1cfd..e9fd4ab9 100644
--- a/build.cm
+++ b/build.cm
@@ -361,7 +361,7 @@ function probe_source_key(setup, file) {
   var deps = null
   var full_content = null
 
-  if (fd.is_file(fail_path)) return {fail: true}
+  if (fd.is_file(fail_path)) return {fail: true, fail_path: fail_path}
 
   if (fd.is_file(deps_path)) {
     deps = filter(array(text(fd.slurp(deps_path)), '\n'), function(p) {
@@ -403,11 +403,13 @@ Build.compile_file = function(pkg, file, target, opts) {
   fd.ensure_dir(build_dir)
 
   var probe = probe_source_key(setup, file)
+  var _fail_msg = null
 
   // Check for cached failure
   if (probe && probe.fail) {
-    if (_opts.verbose) log.build('[verbose] skipping ' + file + ' (cached failure)')
+    _fail_msg = probe.fail_path ? text(fd.slurp(probe.fail_path)) : null
     log.shop('skip ' + file + ' (cached failure)')
+    if (_fail_msg) log.console(file + ':\n' + _fail_msg)
     return null
   }
 
@@ -596,9 +598,12 @@ Build.build_module_dylib = function(pkg, file, target, opts) {
   var ret = null
   var post_probe = null
   var fallback_probe = null
+  var _fail_msg2 = null
 
   if (probe && probe.fail) {
+    _fail_msg2 = probe.fail_path ? text(fd.slurp(probe.fail_path)) : null
     log.shop('skip ' + file + ' (cached failure)')
+    if (_fail_msg2) log.console(file + ':\n' + _fail_msg2)
     return null
   }