cmd/cue: move CUE_DEBUG_PARSER_TRACE to CUE_DEBUG=parsertrace

This was the last of the old debugging flags with a TODO
to consolidate into CUE_DEBUG.

Signed-off-by: Daniel Martí <[email protected]>
Change-Id: I77a5b503c912a9ce383a055b5bfd246a4e0e1ea8
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1214763
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Matthew Sackman <[email protected]>
Unity-Result: CUE porcuepine <[email protected]>

Author: mvdan

cmd/cue/cmd/common.go

@@ -32,6 +32,7 @@ import (
 	"cuelang.org/go/cue/parser"
 	"cuelang.org/go/cue/token"
 	"cuelang.org/go/internal"
+	"cuelang.org/go/internal/cuedebug"
 	"cuelang.org/go/internal/encoding"
 	"cuelang.org/go/internal/filetypes"
 )
@@ -57,8 +58,8 @@ func defaultConfig() (*config, error) {
 					parser.FromVersion(version),
 					parser.ParseComments,
 				}
-				// TODO: consolidate all options into a single CUE_DEBUG variable.
-				if os.Getenv("CUE_DEBUG_PARSER_TRACE") != "" {
+				cuedebug.Init()
+				if cuedebug.Flags.ParserTrace {
 					options = append(options, parser.Trace)
 				}
 				return parser.ParseFile(name, src, options...)

cmd/cue/cmd/help.go

@@ -317,6 +317,8 @@ If an environment variable is unset or empty, sensible default setting is used.
 			Force fields in stucts to be sorted lexicographically.
 		toolsflow
 			Print task dependency mermaid graphs in 'cue cmd'.
+		parsertrace
+			Print a trace of parsed CUE productions.
 
 CUE_EXPERIMENT and CUE_DEBUG are comma-separated lists of key-value strings,
 where the value is a boolean "true" or "1" if omitted. For example:

cmd/cue/cmd/testdata/script/parser_trace.txtar

@@ -1,4 +1,4 @@
-env CUE_DEBUG_PARSER_TRACE=1
+env CUE_DEBUG=parsertrace=1
 
 exec cue vet -c=false schema.cue
 cmp stdout parser-trace.stdout

internal/cuedebug/cuedebug.go

@@ -47,6 +47,9 @@ type Config struct {
 
 	// ToolsFlow causes [cuelang.org/go/tools/flow] to print a task dependency mermaid graph.
 	ToolsFlow bool
+
+	// ParserTrace causes [cuelang.org/go/cue/parser] to print a trace of parsed productions.
+	ParserTrace bool
 }
 
 // Init initializes Flags. Note: this isn't named "init" because we