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hcl/hclsyntax: correctly handle %{ sequence escapes

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In early prototyping the template control sequence introducer was
specified as !{, but that changed to %{ along the way because it seemed
more intuitive and less likely to collide with literal strings.

However, the parser's string literal handling still had remnants of the
old syntax, causing strange quirks in parsing strings that contained
exclamation points.

Now we correctly expect %{ as the control sequence introducer, %%{ as its
escape sequence, and additionally fix a bug where previously template
sequence introduction characters at the end of a string literal would
be silently dropped due to them representing an unterminated escape
sequence.

This fixes #3.
This commit is contained in:
Martin Atkins 2018-01-19 08:11:25 -08:00
parent 0daeda39ff
commit 83451bb547
3 changed files with 292 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
hcl/hclsyntax/parser.go
View File

@ -1531,7 +1531,7 @@ Character:
var detail string
switch {
case len(ch) == 1 && (ch[0] == '$' || ch[0] == '!'):
case len(ch) == 1 && (ch[0] == '$' || ch[0] == '%'):
detail = fmt.Sprintf(
"The characters \"\\%s\" do not form a recognized escape sequence. To escape a \"%s{\" template sequence, use \"%s%s{\".",
ch, ch, ch, ch,
@ -1562,7 +1562,7 @@ Character:
esc = esc[:0]
continue Character
case '$', '!':
case '$', '%':
switch len(esc) {
case 1:
if len(ch) == 1 && ch[0] == esc[0] {
@ -1602,8 +1602,8 @@ Character:
case '$':
esc = append(esc, '$')
continue Character
case '!':
esc = append(esc, '!')
case '%':
esc = append(esc, '%')
continue Character
}
}
@ -1611,6 +1611,42 @@ Character:
}
}
// if we still have an outstanding "esc" when we fall out here then
// the literal ended with an unterminated escape sequence, which we
// must now deal with.
if len(esc) > 0 {
if esc[0] == '\\' {
// An incomplete backslash sequence is an error, since it suggests
// that e.g. the user started writing a \uXXXX sequence but didn't
// provide enough hex digits.
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid escape sequence",
Detail: fmt.Sprintf("The characters %q do not form a recognized escape sequence.", esc),
Subject: &hcl.Range{
Filename: tok.Range.Filename,
Start: hcl.Pos{
Line: pos.Line,
Column: pos.Column,
Byte: pos.Byte,
},
End: hcl.Pos{
Line: pos.Line,
Column: pos.Column + len(esc),
Byte: pos.Byte + len(esc),
},
},
})
}
// This might also be an incomplete $${ or %%{ escape sequence, but
// that's treated as a literal rather than an error since those only
// count as escape sequences when all three characters are present.
ret = append(ret, esc...)
esc = nil
}
return string(ret), diags
}

4
hcl/hclsyntax/parser_template.go
View File

@ -435,7 +435,7 @@ Token:
})
case TokenTemplateControl:
// if the opener is !{~ then we want to eat any trailing whitespace
// if the opener is %{~ then we want to eat any trailing whitespace
// in the preceding literal token, assuming it is indeed a literal
// token.
if canTrimPrev && len(next.Bytes) == 3 && next.Bytes[2] == '~' && len(parts) > 0 {
@ -452,7 +452,7 @@ Token:
diags = append(diags, &hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid template directive",
Detail: "A template directive keyword (\"if\", \"for\", etc) is expected at the beginning of a !{ sequence.",
Detail: "A template directive keyword (\"if\", \"for\", etc) is expected at the beginning of a %{ sequence.",
Subject: &kw.Range,
Context: hcl.RangeBetween(next.Range, kw.Range).Ptr(),
})

250
hcl/hclsyntax/parser_test.go
View File

@ -465,6 +465,256 @@ block "valid" {}
},
},
},
{
"a = \"hello $${true}\"\n",
0,
&Body{
Attributes: Attributes{
"a": {
Name: "a",
Expr: &TemplateExpr{
Parts: []Expression{
&LiteralValueExpr{
Val: cty.StringVal("hello ${true}"),
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 6, Byte: 5},
End: hcl.Pos{Line: 1, Column: 20, Byte: 19},
},
},
},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 5, Byte: 4},
End: hcl.Pos{Line: 1, Column: 21, Byte: 20},
},
},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 1, Column: 21, Byte: 20},
},
NameRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 1, Column: 2, Byte: 1},
},
EqualsRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 3, Byte: 2},
End: hcl.Pos{Line: 1, Column: 4, Byte: 3},
},
},
},
Blocks: Blocks{},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 2, Column: 1, Byte: 21},
},
EndRange: hcl.Range{
Start: hcl.Pos{Line: 2, Column: 1, Byte: 21},
End: hcl.Pos{Line: 2, Column: 1, Byte: 21},
},
},
},
{
"a = \"hello %%{true}\"\n",
0,
&Body{
Attributes: Attributes{
"a": {
Name: "a",
Expr: &TemplateExpr{
Parts: []Expression{
&LiteralValueExpr{
Val: cty.StringVal("hello %{true}"),
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 6, Byte: 5},
End: hcl.Pos{Line: 1, Column: 20, Byte: 19},
},
},
},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 5, Byte: 4},
End: hcl.Pos{Line: 1, Column: 21, Byte: 20},
},
},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 1, Column: 21, Byte: 20},
},
NameRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 1, Column: 2, Byte: 1},
},
EqualsRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 3, Byte: 2},
End: hcl.Pos{Line: 1, Column: 4, Byte: 3},
},
},
},
Blocks: Blocks{},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 2, Column: 1, Byte: 21},
},
EndRange: hcl.Range{
Start: hcl.Pos{Line: 2, Column: 1, Byte: 21},
End: hcl.Pos{Line: 2, Column: 1, Byte: 21},
},
},
},
{
"a = \"hello $$\"\n",
0,
&Body{
Attributes: Attributes{
"a": {
Name: "a",
Expr: &TemplateExpr{
Parts: []Expression{
&LiteralValueExpr{
Val: cty.StringVal("hello $$"),
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 6, Byte: 5},
End: hcl.Pos{Line: 1, Column: 14, Byte: 13},
},
},
},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 5, Byte: 4},
End: hcl.Pos{Line: 1, Column: 15, Byte: 14},
},
},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 1, Column: 15, Byte: 14},
},
NameRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 1, Column: 2, Byte: 1},
},
EqualsRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 3, Byte: 2},
End: hcl.Pos{Line: 1, Column: 4, Byte: 3},
},
},
},
Blocks: Blocks{},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 2, Column: 1, Byte: 15},
},
EndRange: hcl.Range{
Start: hcl.Pos{Line: 2, Column: 1, Byte: 15},
End: hcl.Pos{Line: 2, Column: 1, Byte: 15},
},
},
},
{
"a = \"hello %%\"\n",
0,
&Body{
Attributes: Attributes{
"a": {
Name: "a",
Expr: &TemplateExpr{
Parts: []Expression{
&LiteralValueExpr{
Val: cty.StringVal("hello %%"),
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 6, Byte: 5},
End: hcl.Pos{Line: 1, Column: 14, Byte: 13},
},
},
},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 5, Byte: 4},
End: hcl.Pos{Line: 1, Column: 15, Byte: 14},
},
},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 1, Column: 15, Byte: 14},
},
NameRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 1, Column: 2, Byte: 1},
},
EqualsRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 3, Byte: 2},
End: hcl.Pos{Line: 1, Column: 4, Byte: 3},
},
},
},
Blocks: Blocks{},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 2, Column: 1, Byte: 15},
},
EndRange: hcl.Range{
Start: hcl.Pos{Line: 2, Column: 1, Byte: 15},
End: hcl.Pos{Line: 2, Column: 1, Byte: 15},
},
},
},
{
"a = \"hello!\"\n",
0,
&Body{
Attributes: Attributes{
"a": {
Name: "a",
Expr: &TemplateExpr{
Parts: []Expression{
&LiteralValueExpr{
Val: cty.StringVal("hello!"),
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 6, Byte: 5},
End: hcl.Pos{Line: 1, Column: 12, Byte: 11},
},
},
},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 5, Byte: 4},
End: hcl.Pos{Line: 1, Column: 13, Byte: 12},
},
},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 1, Column: 13, Byte: 12},
},
NameRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 1, Column: 2, Byte: 1},
},
EqualsRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 3, Byte: 2},
End: hcl.Pos{Line: 1, Column: 4, Byte: 3},
},
},
},
Blocks: Blocks{},
SrcRange: hcl.Range{
Start: hcl.Pos{Line: 1, Column: 1, Byte: 0},
End: hcl.Pos{Line: 2, Column: 1, Byte: 13},
},
EndRange: hcl.Range{
Start: hcl.Pos{Line: 2, Column: 1, Byte: 13},
End: hcl.Pos{Line: 2, Column: 1, Byte: 13},
},
},
},
{
"a = foo.bar\n",
0,