perf: some Rego micro-optimizations (#1549)

And simplify invalid-metadata-attribute rule. Doesn't show much
on our benchmarks as most of these locations aren't hit by them.

Signed-off-by: Anders Eknert <anders@styra.com>

Author: anderseknert

bundle/regal/ast/ast.rego

@@ -257,7 +257,7 @@ ref_to_string(ref) := ref[0].value if {
 _ref_part_to_string(0, part) := part.value
 _ref_part_to_string(i, part) := _format_part(part) if i > 0
 
-_format_part(part) := sprintf(".%s", [part.value]) if {
+_format_part(part) := concat("", [".", part.value]) if {
 	part.type == "string"
 	regex.match(`^[a-zA-Z_][a-zA-Z1-9_]*$`, part.value)
 } else := sprintf(`["%v"]`, [part.value]) if {

bundle/regal/lsp/codelens/codelens.rego

@@ -62,7 +62,7 @@ _rule_lens(filename, rule, command, title) := {
 		"command": command,
 		"arguments": [json.marshal({
 			"target": filename,
-			"path": sprintf("%s.%s", [
+			"path": concat(".", [
 				ast.ref_to_string(input["package"].path),
 				ast.ref_static_to_string(rule.head.ref),
 			]),

bundle/regal/lsp/completion/location/location.rego

@@ -91,7 +91,7 @@ word_at(line, col) := word if {
 	word := {
 		"offset_before": count(word_before),
 		"offset_after": count(word_after),
-		"text": sprintf("%s%s", [word_before, word_after]),
+		"text": concat("", [word_before, word_after]),
 	}
 }
 
@@ -110,7 +110,7 @@ ref_at(line, col) := word if {
 	word := {
 		"offset_before": count(word_before),
 		"offset_after": count(word_after),
-		"text": sprintf("%s%s", [word_before, word_after]),
+		"text": concat("", [word_before, word_after]),
 	}
 }
 

bundle/regal/lsp/completion/providers/commonrule/commonrule.rego

@@ -32,7 +32,7 @@ items contains item if {
 		},
 		"textEdit": {
 			"range": location.from_start_of_line_to_position(position),
-			"newText": sprintf("%s ", [label]),
+			"newText": concat("", [label, " "]),
 		},
 	}
 }

bundle/regal/lsp/completion/providers/packagename/packagename.rego

@@ -32,7 +32,7 @@ items contains item if {
 		"detail": "suggested package name based on directory structure",
 		"textEdit": {
 			"range": location.word_range(word, position),
-			"newText": sprintf("%s\n\n", [suggestion]),
+			"newText": concat("", [suggestion, "\n\n"]),
 		},
 	}
 }

bundle/regal/lsp/completion/providers/rulerefs/rulerefs.rego

@@ -57,7 +57,7 @@ _other_package_refs contains ref if {
 _rule_ref_suggestions contains pkg_ref if {
 	some ref in _current_package_refs
 
-	pkg_ref := trim_prefix(ref, sprintf("%s.", [_current_file_package]))
+	pkg_ref := trim_prefix(ref, concat("", [_current_file_package, "."]))
 }
 
 # from imported packages
@@ -68,7 +68,7 @@ _rule_ref_suggestions contains pkg_ref if {
 	startswith(ref, imported_package)
 
 	prefix := regex.replace(imported_package, `\.[^\.]+$`, "")
-	pkg_ref := trim_prefix(ref, sprintf("%s.", [prefix]))
+	pkg_ref := trim_prefix(ref, concat("", [prefix, "."]))
 }
 
 # from any other package

bundle/regal/rules/bugs/impossible-not/impossible_not.rego

@@ -73,7 +73,7 @@ report contains violation if {
 		# note that the "not" isn't present in the AST, so we'll add it manually to the text
 		# in the location to try and make it clear where the issue is (as opposed to just
 		# printing the ref)
-		"text": sprintf("not %s", [_to_string(negated.ref)]),
+		"text": concat(" ", ["not", _to_string(negated.ref)]),
 	}})
 
 	violation := result.fail(rego.metadata.chain(), loc)
@@ -102,7 +102,7 @@ aggregate_report contains violation if {
 		# note that the "not" isn't present in the AST, so we'll add it manually to the text
 		# in the location to try and make it clear where the issue is (as opposed to just
 		# printing the ref)
-		"text": sprintf("not %s", [_to_string(negated.ref)]),
+		"text": concat(" ", ["not", _to_string(negated.ref)]),
 	}})
 
 	violation := result.fail(rego.metadata.chain(), loc)

bundle/regal/rules/bugs/invalid-metadata-attribute/invalid_metadata_attribute.rego

@@ -10,24 +10,16 @@ report contains violation if {
 
 	startswith(trim_space(block[0].text), "METADATA")
 
-	text := _block_to_string(block)
-	attributes := object.keys(yaml.unmarshal(text))
+	text := concat("\n", [entry.text |
+		some i, entry in block
+		i > 0
+	])
 
-	some attribute in attributes
+	some attribute in object.keys(yaml.unmarshal(text))
 	not attribute in ast.comments.metadata_attributes
 
-	violation := result.fail(
-		rego.metadata.chain(),
-		result.location(_find_line(block, attribute)),
-	)
+	violation := result.fail(rego.metadata.chain(), result.location([line |
+		some line in block
+		startswith(trim_space(line.text), concat("", [attribute, ":"]))
+	][0]))
 }
-
-_block_to_string(block) := concat("\n", [entry.text |
-	some i, entry in block
-	i > 0
-])
-
-_find_line(block, attribute) := [line |
-	some line in block
-	startswith(trim_space(line.text), sprintf("%s:", [attribute]))
-][0]

bundle/regal/rules/imports/prefer-package-imports/prefer_package_imports.rego

@@ -51,7 +51,7 @@ aggregate_report contains violation if {
 
 	violation := result.fail(rego.metadata.chain(), {"location": object.union(util.to_location_no_text(location), {
 		"file": entry.aggregate_source.file,
-		"text": sprintf("import %s", [concat(".", array.concat(["data"], path))]),
+		"text": concat("", ["import data.", concat(".", path)]),
 	})})
 }