httpcaddyfile: Fix expression matcher shortcut in snippets (#6288)

caddyconfig/caddyfile/lexer.go

@@ -340,6 +340,8 @@ func (l *lexer) finalizeHeredoc(val []rune, marker string) ([]rune, error) {
 	return []rune(out), nil
 }
 
+// Quoted returns true if the token was enclosed in quotes
+// (i.e. double quotes, backticks, or heredoc).
 func (t Token) Quoted() bool {
 	return t.wasQuoted > 0
 }
@@ -356,6 +358,19 @@ func (t Token) NumLineBreaks() int {
 	return lineBreaks
 }
 
+// Clone returns a deep copy of the token.
+func (t Token) Clone() Token {
+	return Token{
+		File:          t.File,
+		imports:       append([]string{}, t.imports...),
+		Line:          t.Line,
+		Text:          t.Text,
+		wasQuoted:     t.wasQuoted,
+		heredocMarker: t.heredocMarker,
+		snippetName:   t.snippetName,
+	}
+}
+
 var heredocMarkerRegexp = regexp.MustCompile("^[A-Za-z0-9_-]+$")
 
 // isNextOnNewLine tests whether t2 is on a different line from t1

caddyconfig/httpcaddyfile/httptype.go

@@ -1282,19 +1282,24 @@ func matcherSetFromMatcherToken(
 	if tkn.Text == "*" {
 		// match all requests == no matchers, so nothing to do
 		return nil, true, nil
-	} else if strings.HasPrefix(tkn.Text, "/") {
-		// convenient way to specify a single path match
+	}
+
+	// convenient way to specify a single path match
+	if strings.HasPrefix(tkn.Text, "/") {
 		return caddy.ModuleMap{
 			"path": caddyconfig.JSON(caddyhttp.MatchPath{tkn.Text}, warnings),
 		}, true, nil
-	} else if strings.HasPrefix(tkn.Text, matcherPrefix) {
-		// pre-defined matcher
+	}
+
+	// pre-defined matcher
+	if strings.HasPrefix(tkn.Text, matcherPrefix) {
 		m, ok := matcherDefs[tkn.Text]
 		if !ok {
 			return nil, false, fmt.Errorf("unrecognized matcher name: %+v", tkn.Text)
 		}
 		return m, true, nil
 	}
+
 	return nil, false, nil
 }
 
@@ -1430,11 +1435,13 @@ func parseMatcherDefinitions(d *caddyfile.Dispenser, matchers map[string]caddy.M
 	if d.NextArg() {
 		if d.Token().Quoted() {
 			// since it was missing the matcher name, we insert a token
-			// in front of the expression token itself
-			err := makeMatcher("expression", []caddyfile.Token{
-				{Text: "expression", File: d.File(), Line: d.Line()},
-				d.Token(),
-			})
+			// in front of the expression token itself; we use Clone() to
+			// make the new token to keep the same the import location as
+			// the next token, if this is within a snippet or imported file.
+			// see https://github.com/caddyserver/caddy/issues/6287
+			expressionToken := d.Token().Clone()
+			expressionToken.Text = "expression"
+			err := makeMatcher("expression", []caddyfile.Token{expressionToken, d.Token()})
 			if err != nil {
 				return err
 			}

caddytest/integration/caddyfile_adapt/expression_quotes.caddyfiletest

@@ -1,3 +1,7 @@
+(snippet) {
+	@g `{http.error.status_code} == 404`
+}
+
 example.com
 
 @a expression {http.error.status_code} == 400
@@ -14,6 +18,12 @@ abort @d
 
 @e expression `{http.error.status_code} == 404`
 abort @e
+
+@f `{http.error.status_code} == 404`
+abort @f
+
+import snippet
+abort @g
 ----------
 {
 	"apps": {
@@ -106,6 +116,38 @@ abort @e
 													}
 												}
 											]
+										},
+										{
+											"handle": [
+												{
+													"abort": true,
+													"handler": "static_response"
+												}
+											],
+											"match": [
+												{
+													"expression": {
+														"expr": "{http.error.status_code} == 404",
+														"name": "f"
+													}
+												}
+											]
+										},
+										{
+											"handle": [
+												{
+													"abort": true,
+													"handler": "static_response"
+												}
+											],
+											"match": [
+												{
+													"expression": {
+														"expr": "{http.error.status_code} == 404",
+														"name": "g"
+													}
+												}
+											]
 										}
 									]
 								}