Fix up relative path names in baseline header diffs (#1035)

Author: jakebailey

internal/testrunner/compiler_runner.go

@@ -344,6 +344,25 @@ func (c *compilerTest) verifyDiagnostics(t *testing.T, suiteName string, isSubmo
 			Subfolder:           suiteName,
 			IsSubmodule:         isSubmodule,
 			IsSubmoduleAccepted: c.containsUnsupportedOptions(),
+			DiffFixupOld: func(old string) string {
+				var sb strings.Builder
+				sb.Grow(len(old))
+
+				for line := range strings.SplitSeq(old, "\n") {
+					const (
+						relativePrefixNew = "==== "
+						relativePrefixOld = relativePrefixNew + "./"
+					)
+					if rest, ok := strings.CutPrefix(line, relativePrefixOld); ok {
+						line = relativePrefixNew + rest
+					}
+
+					sb.WriteString(line)
+					sb.WriteString("\n")
+				}
+
+				return sb.String()[:sb.Len()-1]
+			},
 		})
 	})
 }

internal/testutil/tsbaseline/type_symbol_baseline.go

@@ -81,6 +81,14 @@ func DoTypeAndSymbolBaseline(
 					}
 				}
 
+				const (
+					relativePrefixNew = "=== "
+					relativePrefixOld = relativePrefixNew + "./"
+				)
+				if rest, ok := strings.CutPrefix(line, relativePrefixOld); ok {
+					line = relativePrefixNew + rest
+				}
+
 				sb.WriteString(line)
 				sb.WriteString("\n")
 			}

testdata/baselines/reference/submodule/compiler/computedEnumMemberSyntacticallyString2(isolatedmodules=false).errors.txt.diff

@@ -1,29 +1,20 @@
 --- old.mergeSymbolReexportInterface.types
 +++ new.mergeSymbolReexportInterface.types
-@@= skipped -15, +15 lines =@@
- >'' : ""
-
-  
--=== ./a.d.ts ===
-+=== a.d.ts ===
+@@= skipped -18, +18 lines =@@
+ === a.d.ts ===
  import '.'
  declare module '.' {
 ->'.' : typeof import("index")
 +>'.' : typeof import(".")
 
    type Row2 = { a: string }
  >Row2 : Row2
-@@= skipped -14, +14 lines =@@
- >s : string
- }
+@@= skipped -13, +13 lines =@@
 
--=== ./index.d.ts ===
-+=== index.d.ts ===
+ === index.d.ts ===
  export type {Row2} from './common';
 ->Row2 : import("common").Row2
 +>Row2 : import("./common").Row2
 
--=== ./common.d.ts ===
-+=== common.d.ts ===
- export interface Row2 { b: string }
- >b : string
+ === common.d.ts ===
+ export interface Row2 { b: string }