ci/lava: Don't print empty lines when changing sections

Make `print_log` section-aware to stop printing newlines whenever a
section changes.
This also caught a bug: the `handle_exception` was sending an exception
type to the `print_log`, now it is fixed.

Signed-off-by: Guilherme Gallo <guilherme.gallo@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33906>

.gitlab-ci/lava/utils/gitlab_section.py

@@ -83,11 +83,13 @@ class GitlabSection:
         )
 
     def __enter__(self):
-        print(self.start())
+        if start_log_line := self.start():
+            print(start_log_line)
         return self
 
     def __exit__(self, exc_type, exc_val, exc_tb):
-        print(self.end())
+        if end_log_line := self.end():
+            print(end_log_line)
 
     def start(self) -> str:
         assert not self.has_finished, "Starting an already finished section"

.gitlab-ci/lava/utils/lava_job.py

@@ -182,7 +182,8 @@ class LAVAJob:
         return lava_lines[:last_line]
 
     def handle_exception(self, exception: Exception):
-        print_log(exception)
+        # Print the exception type and message
+        print_log(f"{type(exception).__name__}: {str(exception)}")
         self.cancel()
         self.exception = exception
 

.gitlab-ci/lava/utils/log_follower.py

@@ -305,8 +305,12 @@ def fix_lava_gitlab_section_log():
             yield first_line
 
 
-
 def print_log(msg: str, *args) -> None:
+    is_section_header = msg.startswith("\x1b[0Ksection_")
+    if is_section_header:
+        print(msg, *args)
+        return
+
     # Reset color from timestamp, since `msg` can tint the terminal color
     ts = datetime.now(tz=UTC)
     ts_str = f"{ts.hour:02}:{ts.minute:02}:{ts.second:02}.{int(ts.microsecond / 1000):03}"