feat: add --git-ignore option

When set, excludes git ignored files from patch creation.

README.md

@@ -130,6 +130,11 @@ team.
 - `--patch-dir`
 
   Specify the name for the directory in which to put the patch files.
+
+- `--git-ignore`
+
+  By default, patch-package creates patches disregarding your git-ignore
+  settings. Set this option to exclude git-ignored files from patches.
 
 #### Nested packages
 

src/index.ts

@@ -19,6 +19,7 @@ const argv = minimist(process.argv.slice(2), {
     "reverse",
     "help",
     "version",
+    "git-ignore",
   ],
   string: ["patch-dir"],
 })
@@ -56,6 +57,7 @@ if (argv.version || argv.v) {
       appPath,
       argv["use-yarn"] ? "yarn" : null,
     )
+    const gitignore = argv["git-ignore"]
     packageNames.forEach((packagePathSpecifier: string) => {
       makePatch({
         packagePathSpecifier,
@@ -64,6 +66,7 @@ if (argv.version || argv.v) {
         includePaths,
         excludePaths,
         patchDir,
+        gitignore,
       })
     })
   } else {
@@ -128,5 +131,11 @@ Usage:
      ${chalk.bold("--patch-dir")}
 
          Specify the name for the directory in which to put the patch files.
+
+     ${chalk.bold("--git-ignore")}
+
+         By default, patch-package creates patches disregarding your git-ignore
+         settings. Set this option to exclude git-ignored files from patches.
+
 `)
 }

src/makePatch.ts

@@ -9,6 +9,7 @@ import {
   mkdirSync,
   unlinkSync,
   mkdirpSync,
+  readFileSync,
 } from "fs-extra"
 import { sync as rimraf } from "rimraf"
 import { copySync } from "fs-extra"
@@ -41,13 +42,15 @@ export function makePatch({
   includePaths,
   excludePaths,
   patchDir,
+  gitignore,
 }: {
   packagePathSpecifier: string
   appPath: string
   packageManager: PackageManager
   includePaths: RegExp
   excludePaths: RegExp
   patchDir: string
+  gitignore: boolean
 }) {
   const packageDetails = getPatchDetailsFromCliString(packagePathSpecifier)
 
@@ -167,15 +170,40 @@ export function makePatch({
 
     // commit the package
     console.info(chalk.grey("•"), "Diffing your files with clean files")
-    writeFileSync(join(tmpRepo.name, ".gitignore"), "!/node_modules\n\n")
     git("init")
     git("config", "--local", "user.name", "patch-package")
     git("config", "--local", "user.email", "[email protected]")
 
+    if (gitignore) {
+      // pertain project's .gitignore and .git/info/exclude
+      // but remove ignoring node_modules/
+      const removeIgnoreNodeModules = (str: string): string =>
+        str.replace(/^\/node_modules\/?$\n/gm, "")
+      const gitIgnorePath = join(appPath, ".gitignore")
+      const gitignoreContent: string = existsSync(gitIgnorePath)
+        ? readFileSync(gitIgnorePath, {
+            encoding: "utf-8",
+          })
+        : ""
+      const gitInfoExcludePath = join(appPath, ".git", "info", "exclude")
+      const gitInfoExcludeContent: string = existsSync(gitInfoExcludePath)
+        ? readFileSync(gitInfoExcludePath, { encoding: "utf-8" })
+        : ""
+      writeFileSync(
+        join(tmpRepo.name, ".gitignore"),
+        [gitInfoExcludeContent, gitignoreContent, "\n"]
+          .map(removeIgnoreNodeModules)
+          .join("\n"),
+      )
+    }
+
     // remove ignored files first
     removeIgnoredFiles(tmpRepoPackagePath, includePaths, excludePaths)
 
-    git("add", "-f", packageDetails.path)
+    const gitAdd = (...args: string[]) =>
+      git("add", ...[...(gitignore ? [] : ["-f"]), ...args])
+
+    gitAdd(packageDetails.path)
     git("commit", "--allow-empty", "-m", "init")
 
     // replace package with user's version
@@ -192,7 +220,7 @@ export function makePatch({
     removeIgnoredFiles(tmpRepoPackagePath, includePaths, excludePaths)
 
     // stage all files
-    git("add", "-f", packageDetails.path)
+    gitAdd(packageDetails.path)
 
     // get diff of changes
     const diffResult = git(