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Differential D2608

templater: add hint to template parse errors to help locate issues
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Authored by ryanmce on Mar 3 2018, 4:49 PM.

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durin42

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hg-reviewers

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rHG80d7fb6c2dec: templater: add hint to template parse errors to help locate issues
rHG8df20b7a39d2: templater: add hint to template parse errors to help locate issues

Summary

Previously, we would print the error name and location, but this isn't as
helpful as we can be. Let's add a hint that shows the location where we
encountered the parse error.

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rHG Mercurial

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Unit Tests Skipped

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ryanmce created this revision.Mar 3 2018, 4:49 PM

Herald added a reviewer: hg-reviewers. · View Herald TranscriptMar 3 2018, 4:49 PM

Herald added a subscriber: mercurial-devel. · View Herald Transcript

We should add a test about templates that contain newlines - it's probably Hard, so feel free to just not be helpful with newline-containing templates for now?

tests/test-command-template.t
2770	Nit: could we make this be "^ here" instead of just the caret?

This revision now requires changes to proceed.Mar 3 2018, 4:55 PM

ryanmce updated this revision to Diff 6484.Mar 3 2018, 5:11 PM

I like similar things in rust too. I am +1 on this.

ryanmce added a child revision: D2609: templater: provide hint for multi-line templates with parse errors.Mar 3 2018, 5:26 PM

ryanmce updated this revision to Diff 6485.

durin42 accepted this revision.Mar 3 2018, 5:42 PM

This revision is now accepted and ready to land.Mar 3 2018, 5:42 PM

ryanmce mentioned this in D2619: revsetlang: add a hint for more useful parse errors.Mar 3 2018, 6:31 PM

Closed by commit rHG8df20b7a39d2: templater: add hint to template parse errors to help locate issues (authored by ryanmce). · Explain WhyMar 3 2018, 6:39 PM

This revision was automatically updated to reflect the committed changes.

yuja added a subscriber: yuja.Mar 3 2018, 7:21 PM

yuja added inline comments.

mercurial/templater.py
147	Perhaps this `pos + 1` is the reason why the error location is sometimes wrong. I'll send a follow up.

ryanmce mentioned this in rHG2a258985ffeb: revsetlang: add a hint for more useful parse errors.Mar 4 2018, 7:55 AM

Revision Contents
Changeset List

		Path
M		mercurial/templater.py (67 lines)
M		tests/test-command-template.t (18 lines)
M		tests/test-export.t (2 lines)
A	M	tests/test-parse-errors.t (19 lines)

Diff	ID	Description	Created	Lint	Unit
Base		Base
Diff 1	6483		Mar 3 2018, 4:49 PM	★	★
Diff 2	6484		Mar 3 2018, 5:11 PM	★	★
Diff 3	6485		Mar 3 2018, 5:26 PM	★	★
Diff 4	6509	rHG8df20b7a39d2957a5705a33ec551bae6965d30de	Mar 3 2018, 5:23 PM	★	★

	Status	Author	Revision
	Closed	ryanmce	D2609 templater: provide hint for multi-line templates with parse errors
	Closed	ryanmce	D2608 templater: add hint to template parse errors to help locate issues

Diff 6485

mercurial/templater.py

	d = program[pos]			d = program[pos]
	if not (d.isalnum() or d == "_"):			if not (d.isalnum() or d == "_"):
	break			break
	pos += 1			pos += 1
	sym = program[s:pos]			sym = program[s:pos]
	yield ('symbol', sym, s)			yield ('symbol', sym, s)
	pos -= 1			pos -= 1
	elif c == term:			elif c == term:
	yield ('end', None, pos + 1)			yield ('end', None, pos + 1)
				yujaUnsubmitted Not Done Perhaps this `pos + 1` is the reason why the error location is sometimes wrong. I'll send a follow up. yuja: Perhaps this `pos + 1` is the reason why the error location is sometimes wrong. I'll send a…
	return			return
	else:			else:
	raise error.ParseError(_("syntax error"), pos)			raise error.ParseError(_("syntax error"), pos)
	pos += 1			pos += 1
	if term:			if term:
	raise error.ParseError(_("unterminated template expansion"), start)			raise error.ParseError(_("unterminated template expansion"), start)
	yield ('end', None, pos)			yield ('end', None, pos)

	raise error.ProgrammingError('unterminated scanning of template')			raise error.ProgrammingError('unterminated scanning of template')

	def _scantemplate(tmpl, start, stop, quote='', raw=False):			def _scantemplate(tmpl, start, stop, quote='', raw=False):
	"""Parse template string into chunks of strings and template expressions"""			"""Parse template string into chunks of strings and template expressions"""
	sepchars = '{' + quote			sepchars = '{' + quote
	unescape = [parser.unescapestr, pycompat.identity][raw]			unescape = [parser.unescapestr, pycompat.identity][raw]
	pos = start			pos = start
	p = parser.parser(elements)			p = parser.parser(elements)
				try:
	while pos < stop:			while pos < stop:
	n = min((tmpl.find(c, pos, stop) for c in sepchars),			n = min((tmpl.find(c, pos, stop) for c in sepchars),
	key=lambda n: (n < 0, n))			key=lambda n: (n < 0, n))
	if n < 0:			if n < 0:
	yield ('string', unescape(tmpl[pos:stop]), pos)			yield ('string', unescape(tmpl[pos:stop]), pos)
	pos = stop			pos = stop
	break			break
	c = tmpl[n:n + 1]			c = tmpl[n:n + 1]
	bs = 0 # count leading backslashes			bs = 0 # count leading backslashes
	if not raw:			if not raw:
	bs = (n - pos) - len(tmpl[pos:n].rstrip('\\'))			bs = (n - pos) - len(tmpl[pos:n].rstrip('\\'))
	if bs % 2 == 1:			if bs % 2 == 1:
	# escaped (e.g. '\{', '\\\{', but not '\\{')			# escaped (e.g. '\{', '\\\{', but not '\\{')
	yield ('string', unescape(tmpl[pos:n - 1]) + c, pos)			yield ('string', unescape(tmpl[pos:n - 1]) + c, pos)
	pos = n + 1			pos = n + 1
	continue			continue
	if n > pos:			if n > pos:
	yield ('string', unescape(tmpl[pos:n]), pos)			yield ('string', unescape(tmpl[pos:n]), pos)
	if c == quote:			if c == quote:
	yield ('end', None, n + 1)			yield ('end', None, n + 1)
	return			return

	parseres, pos = p.parse(tokenize(tmpl, n + 1, stop, '}'))			parseres, pos = p.parse(tokenize(tmpl, n + 1, stop, '}'))
	if not tmpl.endswith('}', n + 1, pos):			if not tmpl.endswith('}', n + 1, pos):
	raise error.ParseError(_("invalid token"), pos)			raise error.ParseError(_("invalid token"), pos)
	yield ('template', parseres, n)			yield ('template', parseres, n)

	if quote:			if quote:
	raise error.ParseError(_("unterminated string"), start)			raise error.ParseError(_("unterminated string"), start)
				except error.ParseError as inst:
				if len(inst.args) > 1: # has location
				loc = inst.args[1]
				# TODO: Opportunity for improvement! If there is a newline in the
				# template, this hint does not point to the right place, so skip.
				if '\n' not in tmpl:
				# We want the caret to point to the place in the template that
				# failed to parse, but in a hint we get a open paren at the
				# start. Therefore, we print "loc" spaces (instead of "loc - 1")
				# to line up the caret with the location of the error.
				inst.hint = tmpl + '\n' + ' ' * (loc) + '^ ' + _('here')
				raise
	yield ('end', None, pos)			yield ('end', None, pos)

	def _unnesttemplatelist(tree):			def _unnesttemplatelist(tree):
	"""Expand list of templates to node tuple			"""Expand list of templates to node tuple

	>>> def f(tree):			>>> def f(tree):
	... print(pycompat.sysstr(prettyformat(_unnesttemplatelist(tree))))			... print(pycompat.sysstr(prettyformat(_unnesttemplatelist(tree))))
	>>> f((b'template', []))			>>> f((b'template', []))

tests/test-command-template.t


	$ echo 'x = "f' >> t			$ echo 'x = "f' >> t
	$ hg log			$ hg log
	hg: parse error at t:3: unmatched quotes			hg: parse error at t:3: unmatched quotes
	[255]			[255]

	$ hg log -T '{date'			$ hg log -T '{date'
	hg: parse error at 1: unterminated template expansion			hg: parse error at 1: unterminated template expansion
				({date
				^ here)
				durin42Unsubmitted Not Done Nit: could we make this be "^ here" instead of just the caret? durin42: Nit: could we make this be "^ here" instead of just the caret?
	[255]			[255]
	$ hg log -T '{date(}'			$ hg log -T '{date(}'
	hg: parse error at 7: not a prefix: end			hg: parse error at 7: not a prefix: end
				({date(}
				^ here)
	[255]			[255]
	$ hg log -T '{date)}'			$ hg log -T '{date)}'
	hg: parse error at 5: invalid token			hg: parse error at 5: invalid token
				({date)}
				^ here)
	[255]			[255]
	$ hg log -T '{date date}'			$ hg log -T '{date date}'
	hg: parse error at 6: invalid token			hg: parse error at 6: invalid token
				({date date}
				^ here)
	[255]			[255]

	$ hg log -T '{}'			$ hg log -T '{}'
	hg: parse error at 2: not a prefix: end			hg: parse error at 2: not a prefix: end
				({}
				^ here)
	[255]			[255]
	$ hg debugtemplate -v '{()}'			$ hg debugtemplate -v '{()}'
	(template			(template
	(group			(group
	None))			None))
	hg: parse error: missing argument			hg: parse error: missing argument
	[255]			[255]

	$ hg tip -T '{get(extras, "branch")\|shortdate}\n'			$ hg tip -T '{get(extras, "branch")\|shortdate}\n'
	abort: incompatible use of template filter 'shortdate'			abort: incompatible use of template filter 'shortdate'
	[255]			[255]

	Error in nested template:			Error in nested template:

	$ hg log -T '{"date'			$ hg log -T '{"date'
	hg: parse error at 2: unterminated string			hg: parse error at 2: unterminated string
				({"date
				^ here)
	[255]			[255]

	$ hg log -T '{"foo{date\|?}"}'			$ hg log -T '{"foo{date\|?}"}'
	hg: parse error at 11: syntax error			hg: parse error at 11: syntax error
				({"foo{date\|?}"}
				^ here)
	[255]			[255]

	Thrown an error if a template function doesn't exist			Thrown an error if a template function doesn't exist

	$ hg tip --template '{foo()}\n'			$ hg tip --template '{foo()}\n'
	hg: parse error: unknown function 'foo'			hg: parse error: unknown function 'foo'
	[255]			[255]

	(template			(template
	(group			(group
	(negate			(negate
	(integer '4')))			(integer '4')))
	(string '\n'))			(string '\n'))
	-4			-4
	$ hg debugtemplate '{(-)}\n'			$ hg debugtemplate '{(-)}\n'
	hg: parse error at 3: not a prefix: )			hg: parse error at 3: not a prefix: )
				({(-)}\n
				^ here)
	[255]			[255]
	$ hg debugtemplate '{(-a)}\n'			$ hg debugtemplate '{(-a)}\n'
	hg: parse error: negation needs an integer argument			hg: parse error: negation needs an integer argument
	[255]			[255]

	top-level integer literal is interpreted as symbol (i.e. variable name):			top-level integer literal is interpreted as symbol (i.e. variable name):

	$ hg debugtemplate -D 1=one -v '{1}\n'			$ hg debugtemplate -D 1=one -v '{1}\n'
	escaped single quotes and errors:			escaped single quotes and errors:

	$ hg log -r 2 -T "{if(rev, '{if(rev, \'foo\')}')}"'\n'			$ hg log -r 2 -T "{if(rev, '{if(rev, \'foo\')}')}"'\n'
	foo			foo
	$ hg log -r 2 -T "{if(rev, '{if(rev, r\'foo\')}')}"'\n'			$ hg log -r 2 -T "{if(rev, '{if(rev, r\'foo\')}')}"'\n'
	foo			foo
	$ hg log -r 2 -T '{if(rev, "{if(rev, \")}")}\n'			$ hg log -r 2 -T '{if(rev, "{if(rev, \")}")}\n'
	hg: parse error at 21: unterminated string			hg: parse error at 21: unterminated string
				({if(rev, "{if(rev, \")}")}\n
				^ here)
	[255]			[255]
	$ hg log -r 2 -T '{if(rev, \"\\"")}\n'			$ hg log -r 2 -T '{if(rev, \"\\"")}\n'
	hg: parse error: trailing \ in string			hg: parse error: trailing \ in string
	[255]			[255]
	$ hg log -r 2 -T '{if(rev, r\"\\"")}\n'			$ hg log -r 2 -T '{if(rev, r\"\\"")}\n'
	hg: parse error: trailing \ in string			hg: parse error: trailing \ in string
	[255]			[255]

tests/test-export.t

	$ hg export -o '%' tip			$ hg export -o '%' tip
	abort: incomplete format spec in output filename			abort: incomplete format spec in output filename
	[255]			[255]
	$ hg export -o '%{"foo"}' tip			$ hg export -o '%{"foo"}' tip
	abort: incomplete format spec in output filename			abort: incomplete format spec in output filename
	[255]			[255]
	$ hg export -o '%m{' tip			$ hg export -o '%m{' tip
	hg: parse error at 3: unterminated template expansion			hg: parse error at 3: unterminated template expansion
				(%m{
				^ here)
	[255]			[255]
	$ hg export -o '%\' tip			$ hg export -o '%\' tip
	abort: invalid format spec '%\' in output filename			abort: invalid format spec '%\' in output filename
	[255]			[255]
	$ hg export -o '\%' tip			$ hg export -o '\%' tip
	abort: incomplete format spec in output filename			abort: incomplete format spec in output filename
	[255]			[255]

tests/test-parse-errors.t

This file was added.

				$ hg init repo
				$ cd repo
				$ echo a > a
				$ hg ci -qAm aa

				simple error
				$ hg log -r . -T '{shortest(node}'
				hg: parse error at 15: unexpected token: end
				({shortest(node}
				^ here)
				[255]

				multi-line
				$ hg log -r . -T 'line 1
				> line2
				> {shortest(node}
				> line4\nline5'
				hg: parse error at 28: unexpected token: end
				[255]