templater: strip single backslash before quotation mark in quoted template db7463aa080f fixed the issue of double escapes, but it made the following template fail with syntax error because of <\">. Strictly speaking, <\"> appears to be invalid in non-string part, but we are likely to escape <"> if surrounded by quotes, and we are used to write such templates by trial and error. [templates] sl = "{tags % \"{ifeq(tag,'tip','',label('log.tag', ' {tag}'))}\"}" So, for backward compatibility between 2.8.1 and 3.4, a single backslash before quotation mark is stripped only in quoted template. We don't care for <\"> in string literal in quoted template, which never worked as expected before. template result --------- ------------------------ {\"\"} parse error "{""}" {""} -> <> "{\"\"}" {""} -> <> {"\""} {"\""} -> <"> '{"\""}' {"\""} -> <"> "{"\""}" parse error (don't care)

--- a/tests/test-command-template.t	Thu May 07 23:18:48 2015 -0700
+++ b/tests/test-command-template.t	Fri May 08 18:11:26 2015 +0900
@@ -2313,6 +2313,25 @@
   <>\n<]>
   <>\n<
 
+Test exception in quoted template. single backslash before quotation mark is
+stripped before parsing:
+
+  $ cat <<'EOF' > escquotetmpl
+  > changeset = "\" \\" \\\" \\\\" {files % \"{file}\"}\n"
+  > EOF
+  $ cd latesttag
+  $ hg log -r 2 --style ../escquotetmpl
+  " \" \" \\" head1
+
+  $ hg log -r 2 -T esc --config templates.esc='{\"invalid\"}\n'
+  hg: parse error at 1: syntax error
+  [255]
+  $ hg log -r 2 -T esc --config templates.esc='"{\"valid\"}\n"'
+  valid
+  $ hg log -r 2 -T esc --config templates.esc="'"'{\'"'"'valid\'"'"'}\n'"'"
+  valid
+  $ cd ..
+
 Test leading backslashes:
 
   $ cd latesttag