From b9a0589067a532c7a508f8f3526d3d019e3ae633 Mon Sep 17 00:00:00 2001
From: Joergen Ibsen <ji@ibse.dk>
Date: Fri, 24 Nov 2017 14:43:23 +0100
Subject: Fix escaping of newlines in string literals

Replace '\n' escape sequence before '\\' to allow a literal backslash
to be inserted before the character 'n'.

Fixes #2682
---
 mesonbuild/mparser.py                              |  8 ++++----
 test cases/common/42 string operations/meson.build | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/mesonbuild/mparser.py b/mesonbuild/mparser.py
index 8400a1a..0465d24 100644
--- a/mesonbuild/mparser.py
+++ b/mesonbuild/mparser.py
@@ -111,6 +111,7 @@ class Lexer:
         par_count = 0
         bracket_count = 0
         col = 0
+        newline_rx = re.compile(r'(?<!\\)((?:\\\\)*)\\n')
         while loc < len(self.code):
             matched = False
             value = None
@@ -139,10 +140,9 @@ class Lexer:
                     elif tid == 'dblquote':
                         raise ParseException('Double quotes are not supported. Use single quotes.', self.getline(line_start), lineno, col)
                     elif tid == 'string':
-                        value = match_text[1:-1]\
-                            .replace(r"\'", "'")\
-                            .replace(r" \\ ".strip(), r" \ ".strip())\
-                            .replace("\\n", "\n")
+                        value = match_text[1:-1].replace(r"\'", "'")
+                        value = newline_rx.sub(r'\1\n', value)
+                        value = value.replace(r" \\ ".strip(), r" \ ".strip())
                     elif tid == 'multiline_string':
                         tid = 'string'
                         value = match_text[3:-3]
diff --git a/test cases/common/42 string operations/meson.build b/test cases/common/42 string operations/meson.build
index d9f8130..babe6cc 100644
--- a/test cases/common/42 string operations/meson.build	
+++ b/test cases/common/42 string operations/meson.build	
@@ -74,3 +74,21 @@ multiline string	'''.strip() == '''multiline string''', 'Newlines badly stripped
 assert('"1.1.20"'.strip('"') == '1.1.20', '" badly stripped')
 assert('"1.1.20"'.strip('".') == '1.1.20', '". badly stripped')
 assert('"1.1.20"   '.strip('" ') == '1.1.20', '". badly stripped')
+
+bs_b = '''\b'''
+bs_bs_b = '''\\b'''
+nl = '''
+'''
+bs_n = '''\n'''
+bs_nl = '''\
+'''
+bs_bs_n = '''\\n'''
+
+assert('\b' == bs_b, 'Single backslash broken')
+assert('\\b' == bs_b, 'Double backslash broken')
+assert('\\\b' == bs_bs_b, 'Three backslash broken')
+assert('\\\\b' == bs_bs_b, 'Four backslash broken')
+assert('\n' == nl, 'Newline escape broken')
+assert('\\n' == bs_n, 'Double backslash broken before n')
+assert('\\\n' == bs_nl, 'Three backslash broken before n')
+assert('\\\\n' == bs_bs_n, 'Four backslash broken before n')
-- 
cgit v1.1