fix: preserve BOM in text tool round-trips (#23797)

packages/opencode/src/tool/apply_patch.ts

@@ -14,6 +14,7 @@ import { AppFileSystem } from "@opencode-ai/shared/filesystem"
 import DESCRIPTION from "./apply_patch.txt"
 import { File } from "../file"
 import { Format } from "../format"
+import * as Bom from "@/util/bom"
 
 const PatchParams = z.object({
   patchText: z.string().describe("The full patch text that describes all changes to be made"),
@@ -59,6 +60,7 @@ export const ApplyPatchTool = Tool.define(
         diff: string
         additions: number
         deletions: number
+        bom: boolean
       }> = []
 
       let totalDiff = ""
@@ -72,11 +74,12 @@ export const ApplyPatchTool = Tool.define(
             const oldContent = ""
             const newContent =
               hunk.contents.length === 0 || hunk.contents.endsWith("\n") ? hunk.contents : `${hunk.contents}\n`
-            const diff = trimDiff(createTwoFilesPatch(filePath, filePath, oldContent, newContent))
+            const next = Bom.split(newContent)
+            const diff = trimDiff(createTwoFilesPatch(filePath, filePath, oldContent, next.text))
 
             let additions = 0
             let deletions = 0
-            for (const change of diffLines(oldContent, newContent)) {
+            for (const change of diffLines(oldContent, next.text)) {
               if (change.added) additions += change.count || 0
               if (change.removed) deletions += change.count || 0
             }
@@ -84,11 +87,12 @@ export const ApplyPatchTool = Tool.define(
             fileChanges.push({
               filePath,
               oldContent,
-              newContent,
+              newContent: next.text,
               type: "add",
               diff,
               additions,
               deletions,
+              bom: next.bom,
             })
 
             totalDiff += diff + "\n"
@@ -104,13 +108,16 @@ export const ApplyPatchTool = Tool.define(
               )
             }
 
-            const oldContent = yield* afs.readFileString(filePath)
+            const source = yield* Bom.readFile(afs, filePath)
+            const oldContent = source.text
             let newContent = oldContent
+            let bom = source.bom
 
             // Apply the update chunks to get new content
             try {
               const fileUpdate = Patch.deriveNewContentsFromChunks(filePath, hunk.chunks)
               newContent = fileUpdate.content
+              bom = fileUpdate.bom
             } catch (error) {
               return yield* Effect.fail(new Error(`apply_patch verification failed: ${error}`))
             }
@@ -136,6 +143,7 @@ export const ApplyPatchTool = Tool.define(
               diff,
               additions,
               deletions,
+              bom,
             })
 
             totalDiff += diff + "\n"
@@ -143,8 +151,8 @@ export const ApplyPatchTool = Tool.define(
           }
 
           case "delete": {
-            const contentToDelete = yield* afs
-              .readFileString(filePath)
+            const source = yield* Bom
+              .readFile(afs, filePath)
               .pipe(
                 Effect.catch((error) =>
                   Effect.fail(
@@ -154,6 +162,7 @@ export const ApplyPatchTool = Tool.define(
                   ),
                 ),
               )
+            const contentToDelete = source.text
             const deleteDiff = trimDiff(createTwoFilesPatch(filePath, filePath, contentToDelete, ""))
 
             const deletions = contentToDelete.split("\n").length
@@ -166,6 +175,7 @@ export const ApplyPatchTool = Tool.define(
               diff: deleteDiff,
               additions: 0,
               deletions,
+              bom: source.bom,
             })
 
             totalDiff += deleteDiff + "\n"
@@ -207,12 +217,12 @@ export const ApplyPatchTool = Tool.define(
           case "add":
             // Create parent directories (recursive: true is safe on existing/root dirs)
 
-            yield* afs.writeWithDirs(change.filePath, change.newContent)
+            yield* afs.writeWithDirs(change.filePath, Bom.join(change.newContent, change.bom))
             updates.push({ file: change.filePath, event: "add" })
             break
 
           case "update":
-            yield* afs.writeWithDirs(change.filePath, change.newContent)
+            yield* afs.writeWithDirs(change.filePath, Bom.join(change.newContent, change.bom))
             updates.push({ file: change.filePath, event: "change" })
             break
 
@@ -220,7 +230,7 @@ export const ApplyPatchTool = Tool.define(
             if (change.movePath) {
               // Create parent directories (recursive: true is safe on existing/root dirs)
 
-              yield* afs.writeWithDirs(change.movePath!, change.newContent)
+              yield* afs.writeWithDirs(change.movePath!, Bom.join(change.newContent, change.bom))
               yield* afs.remove(change.filePath)
               updates.push({ file: change.filePath, event: "unlink" })
               updates.push({ file: change.movePath, event: "add" })
@@ -234,7 +244,9 @@ export const ApplyPatchTool = Tool.define(
         }
 
         if (edited) {
-          yield* format.file(edited)
+          if (yield* format.file(edited)) {
+            yield* Bom.syncFile(afs, edited, change.bom)
+          }
           yield* bus.publish(File.Event.Edited, { file: edited })
         }
       }