hgeditor

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/sh
#
# This is an example of using HGEDITOR to create of diff to review the
# changes while commiting.

# If you want to pass your favourite editor some other parameters
# only for Mercurial, modify this:
case "${EDITOR}" in
    "")
        EDITOR="vi"
        ;;
    emacs)
        EDITOR="$EDITOR -nw"
        ;;
    gvim|vim)
        EDITOR="$EDITOR -f -o"
        ;;
esac


HGTMP=""
cleanup_exit() {
    rm -rf "$HGTMP"
}

# Remove temporary files even if we get interrupted
trap "cleanup_exit" 0 # normal exit
trap "exit 255" HUP INT QUIT ABRT TERM

HGTMP=$(mktemp -d ${TMPDIR-/tmp}/hgeditor.XXXXXX)
[ x$HGTMP != x -a -d $HGTMP ] || {
  echo "Could not create temporary directory! Exiting." 1>&2
  exit 1
}

(
    grep '^HG: changed' "$1" | cut -b 13- | while read changed; do
        "$HG" diff "$changed" >> "$HGTMP/diff"
    done
)

cat "$1" > "$HGTMP/msg"

MD5=$(which md5sum 2>/dev/null) || \
    MD5=$(which md5 2>/dev/null)
[ -x "${MD5}" ] && CHECKSUM=`${MD5} "$HGTMP/msg"`
if [ -s "$HGTMP/diff" ]; then
    $EDITOR "$HGTMP/msg" "$HGTMP/diff" || exit $?
else
    $EDITOR "$HGTMP/msg" || exit $?
fi
[ -x "${MD5}" ] && (echo "$CHECKSUM" | ${MD5} -c >/dev/null 2>&1 && exit 13)

mv "$HGTMP/msg" "$1"

exit $?