contrib/editmerge

templater: make strings in template expressions be "string-escape"-ed correctly

Changeset 64b4f0cd7336 (released with 2.8.1) fixed "recursively
evaluate string literals as templates" problem (issue4102) by moving
the location of "string-escape"-ing from "tokenizer()" to
"compiletemplate()".

But some parts in template expressions below are not processed by
"compiletemplate()", and it may cause unexpected result.

  - 'expr' of 'if(expr, then, else)'
  - 'expr's of 'ifeq(expr, expr, then, else)'
  - 'sep' of 'join(list, sep)'
  - 'text' and 'style' of 'rstdoc(text, style)'
  - 'text' and 'chars' of 'strip(text, chars)'
  - 'pat' and 'repl' of 'sub(pat, repl, expr)'

For example, '\n' of "{join(extras, '\n')}" is not "string-escape"-ed
and treated as a literal '\n'. This breaks "Display the contents of
the 'extra' field, one per line" example in "hg help templates".

Just "string-escape"-ing on each parts above may not work correctly,
because inside expression of nested ones already applies
"string-escape" on string literals. For example:

  - "{join(files, '\n')}" doesn't return "string-escape"-ed string, but
  - "{join(files, if(branch, '\n', '\n'))}" does

To fix this problem, this patch does:

  - introduce "rawstring" token and "runrawstring" method to handle
    strings not to be "string-escape"-ed correctly, and

  - make "runstring" method return "string-escape"-ed string, and
    delay "string-escape"-ing until evaluation

This patch invokes "compiletemplate()" with "strtoken=exp[0]" in
"gettemplate()", because "exp[1]" is not yet evaluated. This code path
is tested via mapping ("expr % '{template}'").

In the other hand, this patch invokes it with "strtoken='rawstring'"
in "_evalifliteral()", because "t" is the result of "arg" evaluation
and it should be "string-escape"-ed if "arg" is "string" expression.

This patch doesn't test "string-escape"-ing on 'expr' of 'if(expr,
then, else)', because it doesn't affect the result.

#!/bin/bash
# A simple script for opening merge conflicts in the editor.
# Use the following Mercurial settings to enable it.
#
# [ui]
# merge = editmerge
#
# [merge-tools]
# editmerge.args=$output
# editmerge.check=changed
# editmerge.premerge=keep

FILE=$1

getlines() {
  grep -n "<<<<<<" $FILE | cut -f1 -d:
}

# editor preference loosely based on http://mercurial.selenic.com/wiki/editor
# hg showconfig is at the bottom though, since it's slow to run (0.15 seconds)
ED=$HGEDITOR
if [ "$ED" = "" ] ; then
  ED=$VISUAL
fi
if [ "$ED" = "" ] ; then
  ED=$EDITOR
fi
if [ "$ED" = "" ] ; then
  ED=$(hg showconfig ui.editor)
fi
if [ "$ED" = "" ] ; then
  echo "merge failed - unable to find editor"
  exit 1
fi

if [ "$ED" = "emacs" ] || [ "$ED" = "nano" ] || [ "$ED" = "vim" ] ; then
  FIRSTLINE=$(getlines | head -n 1)
  PREVIOUSLINE=""

  # open the editor to the first conflict until there are no more
  # or the user stops editing the file
  while [ ! "$FIRSTLINE" = "" ] && [ ! "$FIRSTLINE" = "$PREVIOUSLINE" ] ; do
    $ED +$FIRSTLINE $FILE
    PREVIOUSLINE=$FIRSTLINE
    FIRSTLINE=$(getlines | head -n 1)
  done
else
  $ED $FILE
fi

# get the line numbers of the remaining conflicts
CONFLICTS=$(getlines | sed ':a;N;$!ba;s/\n/, /g')
if [ ! "$CONFLICTS" = "" ] ; then
  echo "merge failed - resolve the conflicts (line $CONFLICTS) then use 'hg resolve --mark'"
  exit 1
fi

exit 0