From b676b0a0652b2dcc7b287551f0d1419d617767b8 Mon Sep 17 00:00:00 2001
From: Matt Ownby <matt@Mac-mini-2.local>
Date: Tue, 20 Jan 2026 19:21:53 -0700
Subject: [PATCH 1/2] save mutation stats after printing them so a CI/CD
 pipeline can optionally take action on the results

---
 src/mutmut/__main__.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/mutmut/__main__.py b/src/mutmut/__main__.py
index 4cad64d5..aa47c1f9 100644
--- a/src/mutmut/__main__.py
+++ b/src/mutmut/__main__.py
@@ -899,6 +899,20 @@ def save_stats():
             stats_time=mutmut.stats_time,
         ), f, indent=4)
 
+def save_cicd_stats(source_file_mutation_data_by_path):
+    s = calculate_summary_stats(source_file_mutation_data_by_path)
+    with open('mutants/mutmut-cicd-stats.json', 'w') as f:
+        json.dump(dict(
+            killed=s.killed,
+            survived=s.survived,
+            total=s.total,
+            no_tests=s.no_tests,
+            skipped=s.skipped,
+            suspicious=s.suspicious,
+            timeout=s.timeout,
+            check_was_interrupted_by_user=s.check_was_interrupted_by_user,
+            segfault=s.segfault
+        ), f, indent=4)
 
 def collect_source_file_mutation_data(*, mutant_names):
     source_file_mutation_data_by_path: Dict[str, SourceFileMutationData] = {}
@@ -1152,6 +1166,9 @@ def read_one_child_exit_status():
     print()
     print(f'{count_tried / t.total_seconds():.2f} mutations/second')
 
+    # save stats so CI/CD pipelines can optionally take action
+    save_cicd_stats(source_file_mutation_data_by_path)
+
     if mutant_names:
         print()
         print('Mutant results')

From 400c5dcec5f12fcc54e0d3da04f3c822a567425d Mon Sep 17 00:00:00 2001
From: Matt Ownby <mownby@solventum.com>
Date: Thu, 22 Jan 2026 18:18:23 -0700
Subject: [PATCH 2/2] added Click command to export cicd mutation data from a
 previous invocation of 'mutmut run'

---
 src/mutmut/__main__.py | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/src/mutmut/__main__.py b/src/mutmut/__main__.py
index aa47c1f9..e982c617 100644
--- a/src/mutmut/__main__.py
+++ b/src/mutmut/__main__.py
@@ -914,6 +914,36 @@ def save_cicd_stats(source_file_mutation_data_by_path):
             segfault=s.segfault
         ), f, indent=4)
 
+# exports CI/CD stats to block pull requests from merging if mutation score is too low, or used in other ways in CI/CD pipelines
+@cli.command()
+def export_cicd_stats():
+    ensure_config_loaded()
+
+    source_file_mutation_data_by_path: Dict[str, SourceFileMutationData] = {}
+
+    for path in walk_source_files():
+        if mutmut.config.should_ignore_for_mutation(path):
+            continue
+
+        meta_path = Path('mutants') / (str(path) + '.meta')
+        if not meta_path.exists():
+            continue
+
+        m = SourceFileMutationData(path=path)
+        m.load()
+        if not m.exit_code_by_key:
+            continue
+
+        source_file_mutation_data_by_path[str(path)] = m
+
+    if not source_file_mutation_data_by_path:
+        print('No previous mutation data found. Run "mutmut run" first.')
+        return
+
+    save_cicd_stats(source_file_mutation_data_by_path)
+    print('Saved CI/CD stats to mutants/mutmut-cicd-stats.json')
+
+
 def collect_source_file_mutation_data(*, mutant_names):
     source_file_mutation_data_by_path: Dict[str, SourceFileMutationData] = {}
 
@@ -1166,9 +1196,6 @@ def read_one_child_exit_status():
     print()
     print(f'{count_tried / t.total_seconds():.2f} mutations/second')
 
-    # save stats so CI/CD pipelines can optionally take action
-    save_cicd_stats(source_file_mutation_data_by_path)
-
     if mutant_names:
         print()
         print('Mutant results')