From cc5708bb4e6d6fb6883e2dd0a03eda2041df6fb4 Mon Sep 17 00:00:00 2001
From: Jeremy Dubreil <jrm@fb.com>
Date: Tue, 22 May 2018 16:11:41 -0700
Subject: [PATCH] [infer] convert absolute paths to relative with respect to
 the common prefix betwen the path and the project root

Reviewed By: mbouaziz

Differential Revision: D8088106

fbshipit-source-id: 3711cf6
---
 infer/src/base/Config.ml     |  9 +++++++++
 infer/src/base/Config.mli    |  2 ++
 infer/src/base/SourceFile.ml |  5 ++++-
 infer/src/base/Utils.ml      | 12 +++++++-----
 infer/src/base/Utils.mli     |  5 +++--
 5 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/infer/src/base/Config.ml b/infer/src/base/Config.ml
index 400a9c93e..1ac1c6c03 100644
--- a/infer/src/base/Config.ml
+++ b/infer/src/base/Config.ml
@@ -1802,6 +1802,13 @@ and reactive_capture =
     "Compile source files only when required by analyzer (clang only)"
 
 
+and relative_path_backtack =
+  CLOpt.mk_int ~long:"backtrack-level" ~default:0 ~meta:"int"
+    "Maximum level of backtracking to convert an absolute path to path relative to the common \
+     prefix between the project root and the path. For instance, with bactraking level 1, it \
+     will convert /my/source/File.java with project root /my/root into ../source/File.java"
+
+
 and report =
   CLOpt.mk_bool ~long:"report" ~default:true
     ~in_help:InferCommand.[(Analyze, manual_generic); (Run, manual_generic)]
@@ -2757,6 +2764,8 @@ and reactive_mode = !reactive || InferCommand.(equal Diff) command
 
 and reactive_capture = !reactive_capture
 
+and relative_path_backtack = !relative_path_backtack
+
 and report = !report
 
 and report_current = !report_current
diff --git a/infer/src/base/Config.mli b/infer/src/base/Config.mli
index a63c09038..65ff3b760 100644
--- a/infer/src/base/Config.mli
+++ b/infer/src/base/Config.mli
@@ -189,6 +189,8 @@ val property_attributes : string
 
 val racerd_issues_dir_name : string
 
+val relative_path_backtack : int
+
 val report : bool
 
 val report_condition_always_true_in_clang : bool
diff --git a/infer/src/base/SourceFile.ml b/infer/src/base/SourceFile.ml
index b39bc5cf9..3a365e44b 100644
--- a/infer/src/base/SourceFile.ml
+++ b/infer/src/base/SourceFile.ml
@@ -52,7 +52,10 @@ let from_abs_path ?(warn_on_error= true) fname =
   let fname_real = try Utils.realpath ~warn_on_error fname with Unix.Unix_error _ -> fname in
   let project_root_real = Utils.realpath ~warn_on_error Config.project_root in
   let models_dir_real = Config.models_src_dir in
-  match Utils.filename_to_relative ~root:project_root_real fname_real with
+  match
+    Utils.filename_to_relative ~backtrack:Config.relative_path_backtack ~root:project_root_real
+      fname_real
+  with
   | Some path ->
       RelativeProjectRoot path
   | None when Config.buck_cache_mode && Filename.check_suffix fname_real "java" ->
diff --git a/infer/src/base/Utils.ml b/infer/src/base/Utils.ml
index 92507404a..804ab7b2d 100644
--- a/infer/src/base/Utils.ml
+++ b/infer/src/base/Utils.ml
@@ -97,19 +97,21 @@ let filename_to_absolute ~root fname =
 
 
 (** Convert an absolute filename to one relative to the given directory. *)
-let filename_to_relative ~root fname =
-  let rec relativize_if_under origin target =
+let filename_to_relative ?(backtrack= 0) ~root fname =
+  let rec relativize_if_under prefix backtrack origin target =
     match (origin, target) with
     | x :: xs, y :: ys when String.equal x y ->
-        relativize_if_under xs ys
+        relativize_if_under prefix backtrack xs ys
+    | _ :: xs, y :: ys when backtrack > 0 ->
+        relativize_if_under (Filename.parent_dir_name :: y :: prefix) (backtrack - 1) xs ys
     | [], [] ->
         Some "."
     | [], ys ->
-        Some (Filename.of_parts ys)
+        Some (Filename.of_parts (prefix @ ys))
     | _ ->
         None
   in
-  relativize_if_under (Filename.parts root) (Filename.parts fname)
+  relativize_if_under [] backtrack (Filename.parts root) (Filename.parts fname)
 
 
 let directory_fold f init path =
diff --git a/infer/src/base/Utils.mli b/infer/src/base/Utils.mli
index f66260dbc..b03d1a6a0 100644
--- a/infer/src/base/Utils.mli
+++ b/infer/src/base/Utils.mli
@@ -25,9 +25,10 @@ val read_file : string -> (string list, string) Result.t
 val filename_to_absolute : root:string -> string -> string
 (** Convert a filename to an absolute one if it is relative, and normalize "." and ".." *)
 
-val filename_to_relative : root:string -> string -> string option
+val filename_to_relative : ?backtrack:int -> root:string -> string -> string option
 (** Convert an absolute filename to one relative to a root directory.  Returns [None] if filename is
-    not under root. *)
+    not under root. The backtrack level sets the maximum level of steps in the parent directories
+    to search for a common prefix *)
 
 (** type for files used for printing *)
 type outfile =