zq: Correct error message when no source is found

This commit fixes an issue where the wrong error message was returned for a
single argument zq invocation where the argument is a valid Zed query but the
query contains no source.

Closes #5110

cli/queryflags/flags.go

@@ -42,17 +42,23 @@ func (f *Flags) ParseSourcesAndInputs(paths []string) ([]string, ast.Seq, *parse
 			// and appears to start with a from or yield operator.
 			// Otherwise, consider it a file.
 			query, sset, err := compiler.Parse(src, f.Includes...)
-			if err == nil {
-				if s, err := semantic.Analyze(context.Background(), query, data.NewSource(storage.NewLocalEngine(), nil), nil); err == nil {
-					if semantic.HasSource(s) {
-						return nil, query, sset, false, nil
-					}
-					if semantic.StartsWithYield(s) {
-						return nil, query, sset, true, nil
-					}
+			if err != nil {
+				return nil, nil, nil, false, singleArgError(src, err)
+			}
+			s, err := semantic.Analyze(context.Background(), query, data.NewSource(storage.NewLocalEngine(), nil), nil)
+			if err != nil {
+				if list, ok := err.(parser.ErrorList); ok {
+					list.SetSourceSet(sset)
 				}
+				return nil, nil, nil, false, err
+			}
+			if semantic.HasSource(s) {
+				return nil, query, sset, false, nil
+			}
+			if semantic.StartsWithYield(s) {
+				return nil, query, sset, true, nil
 			}
-			return nil, nil, nil, false, singleArgError(src, err)
+			return nil, nil, nil, false, singleArgError(src, nil)
 		}
 	}
 	query, sset, err := parser.ParseZed(f.Includes, src)
@@ -92,6 +98,8 @@ func singleArgError(src string, err error) error {
 		for _, line := range strings.Split(list.Error(), "\n") {
 			fmt.Fprintf(&b, "\n   %s", line)
 		}
+	} else if err == nil {
+		b.WriteString("\n - the argument is a valid Zed query but does not begin with a source (e.g., \"file input.zson\") or yield operator")
 	} else {
 		b.WriteString("\n - the argument did not parse as a valid Zed query")
 	}

cmd/zq/ztests/from-pool-error.yaml

@@ -4,6 +4,6 @@ script: |
 outputs:
   - name: stderr
     data: |
-      zq: could not invoke zq with a single argument because:
-       - a file could not be found with the name "from ( pool a )"
-       - the argument did not parse as a valid Zed query
+      zq: "from pool" cannot be used without a lake at line 1, column 8:
+      from ( pool a )
+             ~~~~~~

cmd/zq/ztests/no-files.yaml

@@ -8,4 +8,4 @@ outputs:
     data: |
       zq: could not invoke zq with a single argument because:
        - a file could not be found with the name "doesnotexist"
-       - the argument did not parse as a valid Zed query
+       - the argument is a valid Zed query but does not begin with a source (e.g., "file input.zson") or yield operator

compiler/semantic/op.go

@@ -158,7 +158,7 @@ func (a *analyzer) semSource(source ast.Source) []dag.Op {
 		}
 	case *ast.Pool:
 		if !a.source.IsLake() {
-			a.error(s, errors.New("from pool cannot be used without a lake"))
+			a.error(s, errors.New("\"from pool\" cannot be used without a lake"))
 			return []dag.Op{badOp()}
 		}
 		return a.semPool(s)

compiler/ztests/from-error.yaml

@@ -15,7 +15,7 @@ script: |
 outputs:
   - name: stderr
     data: |
-      from pool cannot be used without a lake at line 1, column 1:
+      "from pool" cannot be used without a lake at line 1, column 1:
       from p
       ~~~~~~
       ===