fix a bug preventing to run the capture only with Buck

Summary: @​public
There was an inconsistency with the type of `stats.json` created by `inferlib.py` and InferAnalyze. This diff cleans up the thing and uses two different files to saves the statistics to clarify what gets created by the analysis, i.e. `proc_stats.json` and what gets created all the time `stats.json`.

Reviewed By: @sblackshear

Differential Revision: D2500517

infer/bin/inferlib.py

@@ -652,16 +652,16 @@ class Infer:
 
     def save_stats(self):
         """Print timing information to infer_out/stats.json"""
-        stats_path = os.path.join(self.args.infer_out, utils.STATS_FILENAME)
+        proc_stats_path = os.path.join(
+            self.args.infer_out,
+            utils.PROC_STATS_FILENAME)
 
-        # capture and compile mode do not create stats.json
-        if not os.path.isfile(stats_path):
-            with open(stats_path, 'w') as stats_file:
-                json.dump(self.stats, stats_file, indent=2)
+        # capture and compile mode do not create proc_stats.json
+        if os.path.isfile(proc_stats_path):
+            with open(proc_stats_path, 'r') as proc_stats_file:
+                proc_stats = json.load(proc_stats_file)
+                self.stats['int'].update(proc_stats)
 
-        with open(stats_path, 'r+') as stats_file:
-            file_stats = json.load(stats_file)
-            self.stats['int'].update(file_stats)
         self.stats['float'] = {
             'capture_time': self.timing.get('capture', 0.0),
             'makefile_generation_time': self.timing.get(
@@ -673,9 +673,11 @@ class Infer:
             'analyzer': self.args.analyzer,
             'infer_version': utils.infer_version()
         }
-            stats_file.seek(0)
+
+        stats_path = os.path.join(self.args.infer_out, utils.STATS_FILENAME)
+        with open(stats_path, 'w') as stats_file:
             json.dump(self.stats, stats_file, indent=2)
-            stats_file.truncate()
+
 
     def close(self):
         if self.args.analyzer != COMPILE:

infer/bin/utils.py

@@ -36,6 +36,7 @@ ANNOT_PROCESSOR_JAR = os.path.join(
 DEFAULT_INFER_OUT = os.path.join(os.getcwd(), 'infer-out')
 CSV_PERF_FILENAME = 'performances.csv'
 STATS_FILENAME = 'stats.json'
+PROC_STATS_FILENAME = 'proc_stats.json'
 
 CSV_REPORT_FILENAME = 'report.csv'
 JSON_REPORT_FILENAME = 'report.json'

infer/src/backend/config.ml

@@ -36,7 +36,7 @@ let default_in_zip_results_dir = "infer"
 
 let default_buck_out = "buck-out"
 
-let stats_filename = "stats.json"
+let proc_stats_filename = "proc_stats.json"
 
 let global_tenv_filename = "global.tenv"
 

infer/src/backend/inferanalyze.ml

@@ -369,7 +369,7 @@ let output_json_file_stats num_files num_procs num_lines =
              ("procedures", `Int num_procs);
              ("lines", `Int num_lines) ] in
   (* write stats file to disk, intentionally overwriting old file if it already exists *)
-  let f = open_out (Filename.concat !Config.results_dir Config.stats_filename) in
+  let f = open_out (Filename.concat !Config.results_dir Config.proc_stats_filename) in
   Yojson.Basic.pretty_to_channel f file_stats
 
 (** create clusters of minimal size in the dependence order, with recursive parts grouped together *)