[PATCH bpf-next v2] scripts/bpf: Print an error when known types list needs updating

[Jakub Sitnicki]

Don't generate a broken bpf_helper_defs.h header if the helper script needs
updating because it doesn't recognize a newly added type. Instead print an
error that explains why the build is failing, clean up the partially
generated header and stop.

v1->v2:
- Switched from temporary file to .DELETE_ON_ERROR.

Fixes: 456a513bb5d4 ("scripts/bpf: Emit an #error directive known types list 
needs updating")
Suggested-by: Andrii Nakryiko <andr...@fb.com>
Signed-off-by: Jakub Sitnicki <ja...@cloudflare.com>
---
 scripts/bpf_helpers_doc.py | 4 ++--
 tools/lib/bpf/Makefile     | 3 +++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/scripts/bpf_helpers_doc.py b/scripts/bpf_helpers_doc.py
index 08300bc024da..7548569e8076 100755
--- a/scripts/bpf_helpers_doc.py
+++ b/scripts/bpf_helpers_doc.py
@@ -488,8 +488,8 @@ class PrinterHelpers(Printer):
             return t
         if t in self.mapped_types:
             return self.mapped_types[t]
-        print("")
-        print("#error \"Unrecognized type '%s', please add it to known 
types!\"" % t)
+        print("Unrecognized type '%s', please add it to known types!" % t,
+              file=sys.stderr)
         sys.exit(1)
 
     seen_helpers = set()
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 75b538577c17..54ff80faa8df 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile
@@ -286,3 +286,6 @@ tags:
 # Declare the contents of the .PHONY variable as phony.  We keep that
 # information in a variable so we can use it in if_changed and friends.
 .PHONY: $(PHONY)
+
+# Delete partially updated (corrupted) files on error
+.DELETE_ON_ERROR:
-- 
2.20.1