Revert r374649: "Reland r374389: [lit] Clean up internal diff's encoding handling"

This series of patches still breaks a Windows bot.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@374682 91177308-0d34-0410-b5e6-96231b3b80d8

utils/lit/lit/builtin_commands/diff.py

@@ -1,7 +1,6 @@
 import difflib
 import functools
 import getopt
-import locale
 import os
 import sys
 
@@ -25,26 +24,37 @@ def getDirTree(path, basedir=""):
         return path, sorted(child_trees)
 
 def compareTwoFiles(flags, filepaths):
+    compare_bytes = False
+    encoding = None
     filelines = []
     for file in filepaths:
-        with open(file, 'rb') as file_bin:
-            filelines.append(file_bin.readlines())
-
-    try:
-        return compareTwoTextFiles(flags, filepaths, filelines,
-                                   locale.getpreferredencoding(False))
-    except UnicodeDecodeError:
         try:
-            return compareTwoTextFiles(flags, filepaths, filelines, "utf-8")
-        except:
-            return compareTwoBinaryFiles(flags, filepaths, filelines)
+            with open(file, 'r') as f:
+                filelines.append(f.readlines())
+        except UnicodeDecodeError:
+            try:
+                with io.open(file, 'r', encoding="utf-8") as f:
+                    filelines.append(f.readlines())
+                encoding = "utf-8"
+            except:
+                compare_bytes = True
+
+    if compare_bytes:
+        return compareTwoBinaryFiles(flags, filepaths)
+    else:
+        return compareTwoTextFiles(flags, filepaths, encoding)
+
+def compareTwoBinaryFiles(flags, filepaths):
+    filelines = []
+    for file in filepaths:
+        with open(file, 'rb') as f:
+            filelines.append(f.readlines())
 
-def compareTwoBinaryFiles(flags, filepaths, filelines):
     exitCode = 0
     if hasattr(difflib, 'diff_bytes'):
         # python 3.5 or newer
         diffs = difflib.diff_bytes(difflib.unified_diff, filelines[0], filelines[1], filepaths[0].encode(), filepaths[1].encode())
-        diffs = [diff.decode(errors="backslashreplace") for diff in diffs]
+        diffs = [diff.decode() for diff in diffs]
     else:
         # python 2.7
         if flags.unified_diff:
@@ -58,14 +68,15 @@ def compareTwoBinaryFiles(flags, filepaths, filelines):
         exitCode = 1
     return exitCode
 
-def compareTwoTextFiles(flags, filepaths, filelines_bin, encoding):
+def compareTwoTextFiles(flags, filepaths, encoding):
     filelines = []
-    for lines_bin in filelines_bin:
-        lines = []
-        for line_bin in lines_bin:
-            line = line_bin.decode(encoding=encoding)
-            lines.append(line)
-        filelines.append(lines)
+    for file in filepaths:
+        if encoding is None:
+            with open(file, 'r') as f:
+                filelines.append(f.readlines())
+        else:
+            with io.open(file, 'r', encoding=encoding) as f:
+                filelines.append(f.readlines())
 
     exitCode = 0
     def compose2(f, g):

utils/lit/tests/Inputs/shtest-shell/diff-encodings.txt

@@ -1,9 +0,0 @@
-# Check that diff falls back to binary mode if it cannot decode a file.
-
-# RUN: diff -u diff-in.bin diff-in.bin
-# RUN: diff -u diff-in.utf16 diff-in.bin && false || true
-# RUN: diff -u diff-in.utf8 diff-in.bin && false || true
-# RUN: diff -u diff-in.bin diff-in.utf8 && false || true
-
-# Fail so lit will print output.
-# RUN: false

utils/lit/tests/Inputs/shtest-shell/diff-in.utf8

@@ -1,3 +0,0 @@
-foo
-bar
-baz

utils/lit/tests/max-failures.py

@@ -8,7 +8,7 @@
 #
 # END.
 
-# CHECK: Failing Tests (28)
+# CHECK: Failing Tests (27)
 # CHECK: Failing Tests (1)
 # CHECK: Failing Tests (2)
 # CHECK: error: argument --max-failures: requires positive integer, but found '0'

utils/lit/tests/shtest-shell.py

@@ -34,58 +34,6 @@
 # CHECK: error: command failed with exit status: 127
 # CHECK: ***
 
-
-# CHECK: FAIL: shtest-shell :: diff-encodings.txt
-# CHECK: *** TEST 'shtest-shell :: diff-encodings.txt' FAILED ***
-
-# CHECK: $ "diff" "-u" "diff-in.bin" "diff-in.bin"
-# CHECK-NOT: error
-
-# CHECK: $ "diff" "-u" "diff-in.utf16" "diff-in.bin"
-# CHECK: # command output:
-# CHECK-NEXT: ---
-# CHECK-NEXT: +++
-# CHECK-NEXT: @@
-# CHECK-NEXT: {{^ .f.o.o.$}}
-# CHECK-NEXT: {{^-.b.a.r.$}}
-# CHECK-NEXT: {{^\+.b.a.r..}}
-# CHECK-NEXT: {{^ .b.a.z.$}}
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "diff" "-u" "diff-in.utf8" "diff-in.bin"
-# CHECK: # command output:
-# CHECK-NEXT: ---
-# CHECK-NEXT: +++
-# CHECK-NEXT: @@
-# CHECK-NEXT: -foo
-# CHECK-NEXT: -bar
-# CHECK-NEXT: -baz
-# CHECK-NEXT: {{^\+.f.o.o.$}}
-# CHECK-NEXT: {{^\+.b.a.r..}}
-# CHECK-NEXT: {{^\+.b.a.z.$}}
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "diff" "-u" "diff-in.bin" "diff-in.utf8"
-# CHECK: # command output:
-# CHECK-NEXT: ---
-# CHECK-NEXT: +++
-# CHECK-NEXT: @@
-# CHECK-NEXT: {{^\-.f.o.o.$}}
-# CHECK-NEXT: {{^\-.b.a.r..}}
-# CHECK-NEXT: {{^\-.b.a.z.$}}
-# CHECK-NEXT: +foo
-# CHECK-NEXT: +bar
-# CHECK-NEXT: +baz
-# CHECK: error: command failed with exit status: 1
-# CHECK: $ "true"
-
-# CHECK: $ "false"
-
-# CHECK: ***
-
-
 # CHECK: FAIL: shtest-shell :: diff-error-1.txt
 # CHECK: *** TEST 'shtest-shell :: diff-error-1.txt' FAILED ***
 # CHECK: $ "diff" "-B" "temp1.txt" "temp2.txt"
@@ -297,4 +245,4 @@
 # CHECK: PASS: shtest-shell :: sequencing-0.txt
 # CHECK: XFAIL: shtest-shell :: sequencing-1.txt
 # CHECK: PASS: shtest-shell :: valid-shell.txt
-# CHECK: Failing Tests (28)
+# CHECK: Failing Tests (27)