From 554090886c69cba9b3389d3ee86f61292aafaed1 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@lukeshu.com>
Date: Sat, 1 May 2021 02:35:29 -0600
Subject: improve error messages

---
 cmd_command.go | 20 ++++++++++----------
 ez.go          |  4 ++--
 util.go        |  4 ++--
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/cmd_command.go b/cmd_command.go
index d66c9ce..de0d4c5 100644
--- a/cmd_command.go
+++ b/cmd_command.go
@@ -83,7 +83,7 @@ func (c CmdCommit) fiCmdWrite(fiw fiWriter) error {
 func init() { parser_registerCmd("commit ", CmdCommit{}) }
 func (CmdCommit) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 	ez := &ezfir{fir: fir}
-	defer ez.Defer(&err)
+	defer ez.Defer("commit", &err)
 
 	// 'commit' SP <ref> LF
 	c := CmdCommit{Ref: trimLinePrefix(ez.ReadLine(), "commit ")}
@@ -108,7 +108,7 @@ func (CmdCommit) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 
 	// 'committer' (SP <name>)? SP LT <email> GT SP <when> LF
 	if !strings.HasPrefix(ez.PeekLine(), "committer ") {
-		ez.Errcheck(errors.Errorf("commit: expected committer command: %q", ez.ReadLine()))
+		ez.Errcheck(errors.Errorf("expected committer command: %q", ez.ReadLine()))
 	}
 	c.Committer, err = ParseIdent(trimLinePrefix(ez.ReadLine(), "committer "))
 	ez.Errcheck(err)
@@ -195,7 +195,7 @@ func (c CmdTag) fiCmdWrite(fiw fiWriter) error {
 func init() { parser_registerCmd("tag ", CmdTag{}) }
 func (CmdTag) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 	ez := &ezfir{fir: fir}
-	defer ez.Defer(&err)
+	defer ez.Defer("tag", &err)
 
 	// 'tag' SP <tagname> LF
 	c := CmdTag{TagName: trimLinePrefix(ez.ReadLine(), "tag ")}
@@ -213,7 +213,7 @@ func (CmdTag) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 
 	// 'from' SP <commit-ish> LF
 	if !strings.HasPrefix(ez.PeekLine(), "from ") {
-		ez.Errcheck(errors.Errorf("tag: expected from command: %q", ez.ReadLine()))
+		ez.Errcheck(errors.Errorf("expected from command: %q", ez.ReadLine()))
 	}
 	c.CommitIsh = trimLinePrefix(ez.ReadLine(), "from ")
 
@@ -224,7 +224,7 @@ func (CmdTag) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 
 	// 'tagger' (SP <name>)? SP LT <email> GT SP <when> LF
 	if !strings.HasPrefix(ez.PeekLine(), "tagger ") {
-		ez.Errcheck(errors.Errorf("tag: expected tagger command: %q", ez.ReadLine()))
+		ez.Errcheck(errors.Errorf("expected tagger command: %q", ez.ReadLine()))
 	}
 	c.Tagger, err = ParseIdent(trimLinePrefix(ez.ReadLine(), "tagger "))
 	ez.Errcheck(err)
@@ -261,7 +261,7 @@ func (c CmdReset) fiCmdWrite(fiw fiWriter) error {
 func init() { parser_registerCmd("reset ", CmdReset{}) }
 func (CmdReset) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 	ez := &ezfir{fir: fir}
-	defer ez.Defer(&err)
+	defer ez.Defer("reset", &err)
 
 	// 'reset' SP <ref> LF
 	c := CmdReset{RefName: trimLinePrefix(ez.ReadLine(), "reset ")}
@@ -305,7 +305,7 @@ func (c CmdBlob) fiCmdWrite(fiw fiWriter) error {
 func init() { parser_registerCmd("blob\n", CmdBlob{}) }
 func (CmdBlob) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 	ez := &ezfir{fir: fir}
-	defer ez.Defer(&err)
+	defer ez.Defer("blob", &err)
 
 	// 'blob' LF
 	_ = ez.ReadLine()
@@ -349,7 +349,7 @@ func (c CmdAlias) fiCmdWrite(fiw fiWriter) error {
 func init() { parser_registerCmd("alias\n", CmdAlias{}) }
 func (CmdAlias) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 	ez := &ezfir{fir: fir}
-	defer ez.Defer(&err)
+	defer ez.Defer("alias", &err)
 
 	// 'alias' LF
 	_ = ez.ReadLine()
@@ -357,14 +357,14 @@ func (CmdAlias) fiCmdRead(fir fiReader) (cmd Cmd, err error) {
 
 	// mark
 	if !strings.HasPrefix(ez.PeekLine(), "mark :") {
-		ez.Errcheck(errors.Errorf("alias: expected mark command: %q", ez.ReadLine()))
+		ez.Errcheck(errors.Errorf("expected mark command: %q", ez.ReadLine()))
 	}
 	c.Mark, err = strconv.Atoi(trimLinePrefix(ez.ReadLine(), "mark :"))
 	ez.Errcheck(err)
 
 	// 'to' SP <commit-ish LF
 	if !strings.HasPrefix(ez.PeekLine(), "to ") {
-		ez.Errcheck(errors.Errorf("alias: expected to command: %q", ez.ReadLine()))
+		ez.Errcheck(errors.Errorf("expected to command: %q", ez.ReadLine()))
 	}
 	c.CommitIsh = trimLinePrefix(ez.ReadLine(), "to ")
 
diff --git a/ez.go b/ez.go
index a1dbfca..79399a8 100644
--- a/ez.go
+++ b/ez.go
@@ -51,7 +51,7 @@ type ezfir struct {
 
 var ezPanic = errors.New("everything is fine")
 
-func (e *ezfir) Defer(err *error) {
+func (e *ezfir) Defer(str string, err *error) {
 	if e.err != nil {
 		r := recover()
 		if r == nil {
@@ -60,7 +60,7 @@ func (e *ezfir) Defer(err *error) {
 		if r != ezPanic {
 			panic(r)
 		}
-		*err = e.err
+		*err = errors.Wrap(e.err, str)
 	}
 }
 
diff --git a/util.go b/util.go
index 544818e..d041168 100644
--- a/util.go
+++ b/util.go
@@ -35,12 +35,12 @@ func trimLinePrefix(line string, prefix string) string {
 func parse_data(line string) (data string, err error) {
 	nl := strings.IndexByte(line, '\n')
 	if nl < 0 {
-		return "", errors.Errorf("data: expected newline: %q", data)
+		return "", errors.Errorf("data: expected newline: %q", line)
 	}
 	head := line[:nl+1]
 	rest := line[nl+1:]
 	if !strings.HasPrefix(head, "data ") {
-		return "", errors.Errorf("data: could not parse: %q", data)
+		return "", errors.Errorf("data: could not parse: %q", line)
 	}
 	if strings.HasPrefix(head, "data <<") {
 		// Delimited format
-- 
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