Fix selective checks handling error tracebacks in CI (apache#28514)

Initially selective check was implemented in the way that it printed
diagnostic output on stdout and the GITHUB_OUTPUT compatible set of
outputs on stderr so that it could be redirected to the GITHUB_OUTPUT
in its entirety. But this turned out to be a bad idea because when
there was an error generated in selective-checks themselves, the
traceback was printed in stderr and redirecting stderr to GITHUB_OUTPUT
swallowed the traceback.

This change reverses the behaviour:

* diagnostic output is printed to stderr
* GITHUB_OUTPUT compatible output is printed to stdout

This way when traceback happens it is printed to stderr and is not
swalleowed by redirection to GITHUB_OUTPUT

.github/workflows/ci.yml

@@ -221,7 +221,8 @@ jobs:
         env:
           PR_LABELS: "${{ steps.source-run-info.outputs.pr-labels }}"
           COMMIT_REF: "${{ github.sha }}"
-        run: breeze ci selective-check 2>> ${GITHUB_OUTPUT}
+          VERBOSE: "false"
+        run: breeze ci selective-check >> ${GITHUB_OUTPUT}
       - name: env
         run: printenv
         env:

dev/breeze/src/airflow_breeze/commands/ci_commands.py

@@ -50,7 +50,7 @@
     option_verbose,
 )
 from airflow_breeze.utils.confirm import Answer, user_confirm
-from airflow_breeze.utils.console import get_console
+from airflow_breeze.utils.console import get_console, get_stderr_console
 from airflow_breeze.utils.custom_param_types import BetterChoice
 from airflow_breeze.utils.docker_command_utils import (
     check_docker_resources,
@@ -179,14 +179,14 @@ def get_changed_files(commit_ref: str | None) -> tuple[str, ...]:
     ]
     result = run_command(cmd, check=False, capture_output=True, text=True)
     if result.returncode != 0:
-        get_console().print(
+        get_stderr_console().print(
             f"[warning] Error when running diff-tree command [/]\n{result.stdout}\n{result.stderr}"
         )
         return ()
     changed_files = tuple(result.stdout.splitlines()) if result.stdout else ()
-    get_console().print("\n[info]Changed files:[/]\n")
-    get_console().print(changed_files)
-    get_console().print()
+    get_stderr_console().print("\n[info]Changed files:[/]\n")
+    get_stderr_console().print(changed_files)
+    get_stderr_console().print()
     return changed_files
 
 
@@ -250,7 +250,7 @@ def selective_check(
         pr_labels=tuple(ast.literal_eval(pr_labels)) if pr_labels else (),
         github_event=github_event,
     )
-    print(str(sc), file=sys.stderr)
+    print(str(sc), file=sys.stdout)
 
 
 @ci_group.command(name="find-newer-dependencies", help="Finds which dependencies are being upgraded.")

dev/breeze/src/airflow_breeze/utils/github_actions.py

@@ -20,11 +20,11 @@
 
 from rich.markup import escape
 
-from airflow_breeze.utils.console import get_console
+from airflow_breeze.utils.console import get_stderr_console
 
 
 def get_ga_output(name: str, value: Any) -> str:
     output_name = name.replace("_", "-")
     printed_value = str(value).lower() if isinstance(value, bool) else value
-    get_console().print(f"[info]{output_name}[/] = [green]{escape(str(printed_value))}[/]")
+    get_stderr_console().print(f"[info]{output_name}[/] = [green]{escape(str(printed_value))}[/]")
     return f"{output_name}={printed_value}"

dev/breeze/src/airflow_breeze/utils/selective_checks.py

@@ -54,7 +54,7 @@
     SelectiveUnitTestTypes,
     all_selective_test_types,
 )
-from airflow_breeze.utils.console import get_console
+from airflow_breeze.utils.console import get_stderr_console
 
 FULL_TESTS_NEEDED_LABEL = "full tests needed"
 DEBUG_CI_RESOURCES_LABEL = "debug ci resources"
@@ -295,16 +295,16 @@ def default_constraints_branch(self) -> str:
     @cached_property
     def full_tests_needed(self) -> bool:
         if not self._commit_ref:
-            get_console().print("[warning]Running everything as commit is missing[/]")
+            get_stderr_console().print("[warning]Running everything as commit is missing[/]")
             return True
         if self._github_event in [GithubEvents.PUSH, GithubEvents.SCHEDULE, GithubEvents.WORKFLOW_DISPATCH]:
-            get_console().print(f"[warning]Full tests needed because event is {self._github_event}[/]")
+            get_stderr_console().print(f"[warning]Full tests needed because event is {self._github_event}[/]")
             return True
         if len(self._matching_files(FileGroupForCi.ENVIRONMENT_FILES, CI_FILE_GROUP_MATCHES)) > 0:
-            get_console().print("[warning]Running everything because env files changed[/]")
+            get_stderr_console().print("[warning]Running everything because env files changed[/]")
             return True
         if FULL_TESTS_NEEDED_LABEL in self._pr_labels:
-            get_console().print(
+            get_stderr_console().print(
                 "[warning]Full tests needed because "
                 f"label '{FULL_TESTS_NEEDED_LABEL}' is in  {self._pr_labels}[/]"
             )
@@ -434,24 +434,24 @@ def _matching_files(self, match_group: T, match_dict: dict[T, list[str]]) -> lis
         self._match_files_with_regexps(matched_files, regexps)
         count = len(matched_files)
         if count > 0:
-            get_console().print(f"[warning]{match_group} matched {count} files.[/]")
-            get_console().print(matched_files)
+            get_stderr_console().print(f"[warning]{match_group} matched {count} files.[/]")
+            get_stderr_console().print(matched_files)
         else:
-            get_console().print(f"[warning]{match_group} did not match any file.[/]")
+            get_stderr_console().print(f"[warning]{match_group} did not match any file.[/]")
         return matched_files
 
     def _should_be_run(self, source_area: FileGroupForCi) -> bool:
         if self.full_tests_needed:
-            get_console().print(f"[warning]{source_area} enabled because we are running everything[/]")
+            get_stderr_console().print(f"[warning]{source_area} enabled because we are running everything[/]")
             return True
         matched_files = self._matching_files(source_area, CI_FILE_GROUP_MATCHES)
         if len(matched_files) > 0:
-            get_console().print(
+            get_stderr_console().print(
                 f"[warning]{source_area} enabled because it matched {len(matched_files)} changed files[/]"
             )
             return True
         else:
-            get_console().print(
+            get_stderr_console().print(
                 f"[warning]{source_area} disabled because it did not match any changed files[/]"
             )
             return False
@@ -503,7 +503,7 @@ def _select_test_type_if_matching(
         count = len(matched_files)
         if count > 0:
             test_types.add(test_type.value)
-            get_console().print(f"[warning]{test_type} added because it matched {count} files[/]")
+            get_stderr_console().print(f"[warning]{test_type} added because it matched {count} files[/]")
         return matched_files
 
     def _get_test_types_to_run(self) -> list[str]:
@@ -528,24 +528,24 @@ def _get_test_types_to_run(self) -> list[str]:
         remaining_files = set(all_source_files) - set(matched_files) - set(kubernetes_files)
         count_remaining_files = len(remaining_files)
         if count_remaining_files > 0:
-            get_console().print(
+            get_stderr_console().print(
                 f"[warning]We should run all tests. There are {count_remaining_files} changed "
                 "files that seems to fall into Core/Other category[/]"
             )
-            get_console().print(remaining_files)
+            get_stderr_console().print(remaining_files)
             candidate_test_types.update(all_selective_test_types())
         else:
             if "Providers" in candidate_test_types:
                 affected_providers = find_all_providers_affected(changed_files=self._files)
                 if len(affected_providers) != 0:
                     candidate_test_types.remove("Providers")
                     candidate_test_types.add(f"Providers[{','.join(sorted(affected_providers))}]")
-            get_console().print(
+            get_stderr_console().print(
                 "[warning]There are no core/other files. Only tests relevant to the changed files are run.[/]"
             )
         sorted_candidate_test_types = list(sorted(candidate_test_types))
-        get_console().print("[warning]Selected test type candidates to run:[/]")
-        get_console().print(sorted_candidate_test_types)
+        get_stderr_console().print("[warning]Selected test type candidates to run:[/]")
+        get_stderr_console().print(sorted_candidate_test_types)
         return sorted_candidate_test_types
 
     @cached_property
@@ -560,7 +560,7 @@ def test_types(self) -> str:
             test_types_to_remove: set[str] = set()
             for test_type in current_test_types:
                 if test_type.startswith("Providers"):
-                    get_console().print(
+                    get_stderr_console().print(
                         f"[warning]Removing {test_type} because the target branch "
                         f"is {self._default_branch} and not main[/]"
                     )