Format XML with xsltproc (#30)

Author: artnc

.dockerignore

@@ -1,3 +1,4 @@
 *
 !.editorconfig
 !entry.ts
+!stylesheet.xml

Dockerfile

@@ -8,6 +8,7 @@ RUN apk add --no-cache --virtual .build-deps \
     python3-dev \
   && apk add --no-cache \
     clang-extra-tools \
+    libxslt \
     nodejs \
     openjdk11-jre-headless \
     py3-pip \
@@ -19,6 +20,7 @@ RUN apk add --no-cache --virtual .build-deps \
     click==8.0.4 \
     isort==5.9.3 \
   && npm install -g \
+    @prettier/plugin-xml@2.0.1 \
     @types/node@16.6.2 \
     prettier@2.3.2 \
     svgo@1.3.2 \

README.md

@@ -2,14 +2,15 @@
 
 This repo currently contains a single [pre-commit](https://pre-commit.com/) hook that internally runs several code formatters in parallel.
 
-- [Prettier](https://github.com/prettier/prettier) v2.3.2 for CSS, HTML, JS, JSX, Markdown, Sass, TypeScript, YAML
+- [Prettier](https://github.com/prettier/prettier) v2.3.2 for CSS, HTML, JS, JSX, Markdown, Sass, TypeScript, XML, YAML
 - [Black](https://github.com/psf/black) v21.7b0<!-- TODO: The next time we upgrade Black, we should also address the isort comment in .editorconfig --> for Python
 - [autoflake](https://github.com/myint/autoflake) v1.4 for Python
 - [isort](https://github.com/PyCQA/isort) v5.9.3 for Python
 - [google-java-format](https://github.com/google/google-java-format) v1.11.0 for Java
 - [ktfmt](https://github.com/facebookincubator/ktfmt) v0.28 for Kotlin
 - [scalafmt](https://scalameta.org/scalafmt/) v2.7.5 for Scala
 - [shfmt](https://github.com/mvdan/sh) v3.3.1 for Shell
+- [xsltproc](http://www.xmlsoft.org/xslt/xsltproc.html) from libxslt v10135 for XML
 - [terraform fmt](https://github.com/hashicorp/terraform) v0.11.14 and v0.12.29 for Terraform
 - [ClangFormat](https://clang.llvm.org/docs/ClangFormat.html) v11.1.0 for Protobuf
 - [SVGO](https://github.com/svg/svgo) v1.3.2 for SVG

entry.ts

@@ -79,6 +79,7 @@ const enum HookName {
   Shfmt = "shfmt",
   Svgo = "SVGO",
   TerraformFmt = "terraform fmt",
+  Xsltproc = "xsltproc",
 }
 
 /** Arguments passed into this hook via the `args` pre-commit config key */
@@ -217,8 +218,8 @@ const HOOKS: Record<HookName, LockableHook> = {
         "all",
         ...sources,
       ),
-    include: /\.(css|html?|markdown|md|scss|tsx?|ya?ml)$/,
-    runAfter: [HookName.Sed],
+    include: /\.(css|html?|markdown|md|scss|tsx?|xml|ya?ml)$/,
+    runAfter: [HookName.Sed, HookName.Xsltproc],
   }),
   [HookName.Scalafmt]: createLockableHook({
     action: sources =>
@@ -396,6 +397,16 @@ const HOOKS: Record<HookName, LockableHook> = {
     include: /\.tf$/,
     runAfter: [HookName.Sed],
   }),
+  [HookName.Xsltproc]: createLockableHook({
+    action: sources =>
+      Promise.all(
+        sources.map(source =>
+          run("xsltproc", "--output", source, "/stylesheet.xml", source),
+        ),
+      ),
+    include: /\.xml$/,
+    runAfter: [HookName.Sed],
+  }),
 };
 
 /** Files that match this pattern should never be processed */

stylesheet.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<xsl:stylesheet
+  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+  xmlns:android="http://schemas.android.com/apk/res/android"
+  version="1.0"
+>
+  <!-- Indent output -->
+  <xsl:strip-space elements="*" />
+  <xsl:output encoding="utf-8" indent="yes" method="xml" />
+  <!-- Document root -->
+  <xsl:template match="/">
+    <xsl:apply-templates />
+  </xsl:template>
+  <!-- Sort non-text nodes' attributes -->
+  <xsl:template match="*">
+    <xsl:copy>
+      <xsl:for-each select="@*">
+        <xsl:sort select="name(.)" />
+        <xsl:copy />
+      </xsl:for-each>
+      <xsl:apply-templates />
+    </xsl:copy>
+  </xsl:template>
+  <!-- Leave text nodes untouched -->
+  <xsl:template match="text()|comment()|processing-instruction()">
+    <xsl:copy />
+  </xsl:template>
+</xsl:stylesheet>

test/after/hello.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<androidx.constraintlayout.widget.ConstraintLayout
+  xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto"
+  xmlns:tools="http://schemas.android.com/tools"
+  android:layout_height="wrap_content"
+  android:layout_width="match_parent"
+>
+  <TextView
+    android:id="@+id/body"
+    android:layout_width="wrap_content"
+    style="@style/foobar"
+    tools:text="Hello world"
+  />
+</androidx.constraintlayout.widget.ConstraintLayout>

test/before/hello.xml

@@ -0,0 +1 @@
+<?xml version="1.0" encoding="utf-8" ?><androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="wrap_content"><TextView style="@style/foobar" android:id="@+id/body" android:layout_width="wrap_content" tools:text="Hello world" /></androidx.constraintlayout.widget.ConstraintLayout>