From e980a3d8856ec3b4f11daa7e5ec417ad4f5c5256 Mon Sep 17 00:00:00 2001 From: Robert Griesemer Date: Fri, 10 Jun 2016 10:27:37 -0700 Subject: [PATCH] go/parser: document that parse functions need valid token.FileSet + panic with explicit error if no file set it provided (Not providing a file set is invalid use of the API; panic is the appropriate action rather than returning an error.) Fixes #16018. Change-Id: I207f5b2a2e318d65826bdd9522fce46d614c24ee Reviewed-on: https://go-review.googlesource.com/24010 Run-TryBot: Robert Griesemer Reviewed-by: Ian Lance Taylor TryBot-Result: Gobot Gobot --- src/go/parser/interface.go | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/src/go/parser/interface.go b/src/go/parser/interface.go index c6fd93240afe6..bff79cab4621a 100644 --- a/src/go/parser/interface.go +++ b/src/go/parser/interface.go @@ -73,7 +73,7 @@ const ( // // The mode parameter controls the amount of source text parsed and other // optional parser functionality. Position information is recorded in the -// file set fset. +// file set fset, which must not be nil. // // If the source couldn't be read, the returned AST is nil and the error // indicates the specific failure. If the source was read but syntax @@ -82,6 +82,10 @@ const ( // are returned via a scanner.ErrorList which is sorted by file position. // func ParseFile(fset *token.FileSet, filename string, src interface{}, mode Mode) (f *ast.File, err error) { + if fset == nil { + panic("parser.ParseFile: no token.FileSet provided (fset == nil)") + } + // get source text, err := readSource(filename, src) if err != nil { @@ -125,7 +129,8 @@ func ParseFile(fset *token.FileSet, filename string, src interface{}, mode Mode) // // If filter != nil, only the files with os.FileInfo entries passing through // the filter (and ending in ".go") are considered. The mode bits are passed -// to ParseFile unchanged. Position information is recorded in fset. +// to ParseFile unchanged. Position information is recorded in fset, which +// must not be nil. // // If the directory couldn't be read, a nil map and the respective error are // returned. If a parse error occurred, a non-nil but incomplete map and the @@ -169,9 +174,14 @@ func ParseDir(fset *token.FileSet, path string, filter func(os.FileInfo) bool, m // ParseExprFrom is a convenience function for parsing an expression. // The arguments have the same meaning as for Parse, but the source must -// be a valid Go (type or value) expression. +// be a valid Go (type or value) expression. Specifically, fset must not +// be nil. // func ParseExprFrom(fset *token.FileSet, filename string, src interface{}, mode Mode) (ast.Expr, error) { + if fset == nil { + panic("parser.ParseExprFrom: no token.FileSet provided (fset == nil)") + } + // get source text, err := readSource(filename, src) if err != nil {