[DB] Don't fail hard when realpath fails

Summary: When infer runs on preprocessed source, original files may not be around anymore. Don't crash infer when that happens.

Reviewed By: jvillard, jberdine

Differential Revision: D4258285

fbshipit-source-id: a19569c

infer/lib/python/inferlib/issues.py

@@ -171,10 +171,8 @@ def _text_of_report_list(project_root, reports, bugs_txt_path, limit=None,
 
 
 def _is_user_visible(project_root, report):
-    filename = report[JSON_INDEX_FILENAME]
     kind = report[JSON_INDEX_KIND]
-    return (os.path.isfile(os.path.join(project_root, filename)) and
-            kind in [ISSUE_KIND_ERROR, ISSUE_KIND_WARNING, ISSUE_KIND_ADVICE])
+    return kind in [ISSUE_KIND_ERROR, ISSUE_KIND_WARNING, ISSUE_KIND_ADVICE]
 
 
 def print_and_save_errors(infer_out, project_root, json_report, bugs_out,

infer/lib/python/inferlib/source.py

@@ -11,6 +11,7 @@ from __future__ import print_function
 from __future__ import unicode_literals
 
 import codecs
+import os
 
 from . import colorize, config
 
@@ -67,6 +68,8 @@ def build_source_context(source_name, mode, report_line):
     # get source excerpt
     line_number = 1
     excerpt = ''
+    if not os.path.isfile(source_name):
+        return ''
     with codecs.open(source_name, 'r',
                      encoding=config.CODESET, errors="replace") as source_file:
         # avoid going past the end of the file

infer/src/backend/InferPrint.re

@@ -386,13 +386,6 @@ let should_report (issue_kind: Exceptions.err_kind) issue_type error_desc =>
     }
   };
 
-let is_file source_file =>
-  switch (Unix.stat (DB.source_file_to_abs_path source_file)) {
-  | {st_kind: S_REG | S_LNK} => true
-  | _ => false
-  | exception Unix.Unix_error _ => false
-  };
-
 let module IssuesCsv = {
   let csv_issues_id = ref 0;
   let pp_header fmt () =>
@@ -427,8 +420,7 @@ let module IssuesCsv = {
         };
       if (
         in_footprint &&
-        error_filter source_file error_desc error_name &&
-        should_report ekind error_name error_desc && is_file source_file
+        error_filter source_file error_desc error_name && should_report ekind error_name error_desc
       ) {
         let err_desc_string = error_desc_to_csv_string error_desc;
         let err_advice_string = error_advice_to_csv_string error_desc;
@@ -504,8 +496,7 @@ let module IssuesJson = {
       if (
         in_footprint &&
         error_filter source_file error_desc error_name &&
-        should_report_source_file &&
-        should_report ekind error_name error_desc && is_file source_file
+        should_report_source_file && should_report ekind error_name error_desc
       ) {
         let kind = Exceptions.err_kind_string ekind;
         let bug_type = Localise.to_string error_name;
@@ -826,8 +817,7 @@ let module Stats = {
           let error_strs = {
             let pp1 fmt () => F.fprintf fmt "%d: %s" stats.nerrors type_str;
             let pp2 fmt () =>
-              F.fprintf
-                fmt "  %a:%d" DB.source_file_pp loc.Location.file loc.Location.line;
+              F.fprintf fmt "  %a:%d" DB.source_file_pp loc.Location.file loc.Location.line;
             let pp3 fmt () => F.fprintf fmt "  (%a)" Localise.pp_error_desc error_desc;
             [pp_to_string pp1 (), pp_to_string pp2 (), pp_to_string pp3 ()]
           };

infer/src/base/DB.ml

@@ -48,14 +48,14 @@ let rel_path_from_abs_path root fname =
   else None (* The project root is not a prefix of the file name *)
 
 let source_file_from_abs_path fname =
-  (* IMPORTANT: results of realpath are cached to not ruin performance *)
-  let fname_real = realpath fname in
-  let project_root_real = realpath Config.project_root in
-  let models_dir_real = Config.models_src_dir in
   if Filename.is_relative fname then
     (failwithf
        "ERROR: Path %s is relative, when absolute path was expected .@."
        fname);
+  (* try to get realpath of source file. Use original if it fails *)
+  let fname_real = try realpath fname with Unix.Unix_error _ -> fname in
+  let project_root_real = realpath Config.project_root in
+  let models_dir_real = Config.models_src_dir in
   match rel_path_from_abs_path project_root_real fname_real with
   | Some path -> RelativeProjectRoot path
   | None -> (

infer/src/base/Utils.ml

@@ -600,8 +600,19 @@ let rec create_path path =
 let realpath_cache = Hashtbl.create 1023
 
 let realpath path =
-  try Hashtbl.find realpath_cache path
-  with Not_found ->
-    let realpath = Core.Std.Filename.realpath path in
-    Hashtbl.add realpath_cache path realpath;
-    realpath
+  match Hashtbl.find realpath_cache path with
+  | exception Not_found -> (
+      match Core.Std.Filename.realpath path with
+      | realpath ->
+          Hashtbl.add realpath_cache path (Ok realpath);
+          realpath
+      | exception Unix.Unix_error (code, f, arg) ->
+          F.eprintf
+            "WARNING: Failed to resolve file %s with \"%s\" \n@." arg (Unix.error_message code);
+          (* cache failures as well *)
+          Hashtbl.add realpath_cache path (Error (code, f, arg));
+          raise (Unix.Unix_error (code, f, arg))
+
+    )
+  | Ok path -> path
+  | Error (code, f, arg) -> raise (Unix.Unix_error (code, f, arg))

infer/tests/build_systems/codetoanalyze/preprocessed.c

@@ -0,0 +1,16 @@
+# 1 "/tmp/removed_src.c"
+# 1 "<built-in>" 1
+# 1 "<built-in>" 3
+# 330 "<built-in>" 3
+# 1 "<command line>" 1
+# 1 "<built-in>" 2
+# 1 "/tmp/removed_src.c" 2
+
+# 1 "/tmp/removed_header.h" 1
+
+void fun();
+# 3 "/tmp/removed_src.c" 2
+
+int deref(int* a) { return *a; }
+
+int test() { return deref(0); }

infer/tests/build_systems/preprocessed/Makefile

@@ -0,0 +1,18 @@
+# Copyright (c) 2016 - present Facebook, Inc.
+# All rights reserved.
+#
+# This source code is licensed under the BSD style license found in the
+# LICENSE file in the root directory of this source tree. An additional grant
+# of patent rights can be found in the PATENTS file in the same directory.
+
+TESTS_DIR = ../..
+
+ANALYZER = infer
+CLANG_OPTIONS = -c
+INFER_OPTIONS = --report-custom-error --developer-mode --headers --project-root ../codetoanalyze
+INFERPRINT_OPTIONS = --issues-tests
+
+SOURCES = \
+  ../codetoanalyze/preprocessed.c
+
+include $(TESTS_DIR)/clang.make

infer/tests/build_systems/preprocessed/issues.exp

@@ -0,0 +1 @@
+/tmp/removed_src.c, test, 0, NULL_DEREFERENCE, [start of procedure test(),start of procedure deref()]