From c152f69b6082c769cc52b37898ea771b3245648f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fabian=20Gra=C3=9Fl?= <mail@fabiangrassl.de>
Date: Fri, 30 Oct 2026 17:17:21 +0100
Subject: [PATCH 1/3] The patch carries the chart series in the order the
 schema names them
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The patch this package applies is the difference between PHPPresentation 1.2.0 and
upstream's branch, and the branch has moved: a chart's series is now written in the
order the schema names it — the shape properties right after the title rather than
after the data points and the data labels, and the separator of the data labels of a
doughnut before the leader lines rather than after them. PowerPoint repairs a chart
written the other way round before it opens it.

So the patch is regenerated against the branch that carries the fix, and the commit it
is pinned to in the manifest moves with it. Nothing this library draws changes: it
writes no chart, and the patch is upstream's branch whole.
---
 CHANGELOG.md  | 15 +++++++++++++++
 composer.json |  7 ++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a816266..815b743 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,21 @@ All notable changes to this project are documented here. The format follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and the project follows
 [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Changed
+
+- **The patch carries one more fix from upstream.** A chart's series is written in the
+  order the schema names it: the shape properties right after the title rather than after
+  the data points and the data labels, and the separator of the data labels of a doughnut
+  before the leader lines rather than after them. PowerPoint repairs a chart written the
+  other way round before it opens it
+  ([#695](https://github.com/PHPOffice/PHPPresentation/issues/695),
+  [#1044](https://github.com/PHPOffice/PHPPresentation/pull/1044)).
+
+  This library writes no chart, so nothing it draws changes: the patch is upstream's
+  branch whole, and the fix belongs to that branch rather than to this one.
+
 ## [0.3.0] - 2026-10-30
 
 ### Added
diff --git a/composer.json b/composer.json
index 4064e28..4815a58 100644
--- a/composer.json
+++ b/composer.json
@@ -39,9 +39,9 @@
         "patches": {
             "phpoffice/phppresentation": [
                 {
-                    "description": "PHPPresentation 1.2.0 brought up to upstream's master, with the fixes that give a picture the path, the bytes and the name it was read from, and that find the folder of a part of a package with the slashes of the package",
-                    "url": "https://raw.githubusercontent.com/markdown-office/PHPPresentation/9aa3f4624f1cab54fc5d275397c2fc59cf6f276d/patches/phpoffice-phppresentation-1.2.0-to-master.patch",
-                    "sha256": "0b8f7c150f7ba5d12671fb9e211c9f1a4db549d7609239f49c0cea707a190551"
+                    "description": "PHPPresentation 1.2.0 brought up to upstream's master, with the fixes that give a picture the path, the bytes and the name it was read from, that find the folder of a part of a package with the slashes of the package, and that write a chart series in the order the schema names it",
+                    "url": "https://raw.githubusercontent.com/markdown-office/PHPPresentation/92c2c64ca20a6b3febf6512e892b21a3c0ae4b56/patches/phpoffice-phppresentation-1.2.0-to-master.patch",
+                    "sha256": "67ce1a44e76e4dc23639fefee365ec811ef7a763331343bde468ae781bf5427a"
                 }
             ]
         }
@@ -69,6 +69,7 @@
     "scripts": {
         "test": "pest",
         "test:unit": "pest --testsuite=unit",
+        "test:conformance": "pest --testsuite=conformance",
         "test:readme": "pest --testsuite=readme",
         "test:coverage": "php -d memory_limit=-1 vendor/bin/pest --coverage --min=100",
         "analyse": "tools/phpstan.sh",

From 30ab6ffa34b806ba8351a002e383808e44afaf62 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fabian=20Gra=C3=9Fl?= <mail@fabiangrassl.de>
Date: Fri, 30 Oct 2026 17:17:32 +0100
Subject: [PATCH 2/3] Every deck the library writes is checked against the
 schema Microsoft's validator reads
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Nothing in the suite could see that a deck is outside the schema. The decks were
checked against the parts they carry, and a deck whose XML is outside the schema
passes every one of those checks and opens in PowerPoint as `[Repaired]`.

The gate is Microsoft's own validator — the one the Open XML SDK Productivity Tool
uses — run over every deck the library writes. It is a program in
`tools/ooxml-validator/` rather than a dependency: nothing that ships with the library
needs it, and the suite runs without it. A machine with no .NET SDK says what is
missing and skips the test, because a green tick for a check that never ran is a check
nobody made; the job that runs the gate installs the SDK, so it cannot skip itself
there.

The decks are the ones the gallery is built from, and the plan of them is the file the
script that writes them holds it in: `examples/decks.php`. A list of its own in the
test would be a second answer to a question that already has one, and the two would
drift — a deck the gallery no longer builds and the gate still checks, which is the
worse of the two.
---
 .github/workflows/tests.yml                  |  43 ++++++
 .gitignore                                   |   4 +
 CHANGELOG.md                                 |  13 ++
 CONTRIBUTING.md                              |  11 ++
 examples/build.php                           |  26 +---
 examples/decks.php                           |  41 +++++
 phpunit.xml.dist                             |   8 +
 tests/Conformance/ooxml.php                  | 149 +++++++++++++++++++
 tests/Readme/examples-decks.php              |   8 +-
 tools/ooxml-validator/Program.cs             | 110 ++++++++++++++
 tools/ooxml-validator/README.md              |  38 +++++
 tools/ooxml-validator/ooxml-validator.csproj |  25 ++++
 12 files changed, 447 insertions(+), 29 deletions(-)
 create mode 100644 examples/decks.php
 create mode 100644 tests/Conformance/ooxml.php
 create mode 100644 tools/ooxml-validator/Program.cs
 create mode 100644 tools/ooxml-validator/README.md
 create mode 100644 tools/ooxml-validator/ooxml-validator.csproj

diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 83c92b7..dbd1eb7 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -81,6 +81,49 @@ jobs:
       - name: Test
         run: vendor/bin/pest
 
+  # The decks the library writes, checked against the schema Microsoft's own validator
+  # reads.
+  #
+  # Its own job rather than a step in the test matrix, because the validator is a .NET
+  # program: the SDK it is built and run with is a second toolchain, and the job that
+  # installs it is the job that runs the gate.
+  #
+  # `--fail-on-skipped` because the test skips itself where the .NET SDK is missing, and
+  # a skipped test is a green tick for a check that never ran. The rasteriser is
+  # installed for the same reason: the deck carrying an SVG cannot be written without
+  # one, and a gate that checked one deck fewer than the gallery holds would be a gate
+  # that says less than it says.
+  conformance:
+    name: valid OOXML
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4
+
+      - uses: shivammathur/setup-php@f3e473d116dcccaddc5834248c87452386958240 # v2
+        with:
+          php-version: '8.5'
+          coverage: none
+          tools: composer:v2
+          extensions: imagick
+
+      - uses: actions/setup-dotnet@67a3573c9a986a3f9c594539f4ab511d57bb3ce9 # v4
+        with:
+          dotnet-version: '8.0.x'
+
+      # The delegate ImageMagick hands an SVG to. Without one that can draw a letter the
+      # picture in the deck is refused rather than drawn, and the deck is not written at
+      # all — which would leave the gate checking one deck fewer than the gallery holds.
+      - name: A rasteriser that can draw an SVG
+        run: |
+          sudo apt-get update
+          sudo apt-get install --yes --no-install-recommends librsvg2-bin
+
+      - name: Install
+        run: composer install --prefer-dist --no-interaction --no-progress
+
+      - name: The decks are valid OOXML
+        run: vendor/bin/pest --testsuite=conformance --fail-on-skipped
+
   coverage:
     name: coverage
     runs-on: ubuntu-latest
diff --git a/.gitignore b/.gitignore
index 646b245..48b1714 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,6 +30,10 @@
 # The OOXML schemas `tools/install-ooxml-schemas.php` fetches and checksums.
 /tools/ooxml-schemas/
 
+# The validator's own build output, which the .NET SDK writes beside the project.
+/tools/ooxml-validator/bin/
+/tools/ooxml-validator/obj/
+
 # The fonts `tools/generate-font-metrics.php` fetches and checksums.
 /tools/fonts/
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 815b743..98e8614 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,19 @@ All notable changes to this project are documented here. The format follows
 
 ## [Unreleased]
 
+### Added
+
+- **Every deck the library writes is checked against the schema Microsoft's own validator
+  reads.** Nothing in the suite could see that before: the decks were checked against the
+  parts they carry, and a deck whose XML is outside the schema passes every one of those
+  checks and opens in PowerPoint as `[Repaired]`.
+
+  The validator is Microsoft's own — the one the Open XML SDK Productivity Tool uses — and
+  it is a program in `tools/ooxml-validator/` rather than a dependency: nothing that ships
+  with the library needs it. A machine without the .NET SDK runs the rest of the suite and
+  says what is missing, and the job that runs the gate in continuous integration installs
+  it, so the gate cannot skip itself there.
+
 ### Changed
 
 - **The patch carries one more fix from upstream.** A chart's series is written in the
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index a1711a3..2fa63bf 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -146,6 +146,17 @@ it would import the file through a lossy converter and report nothing about whet
 is valid. PowerPoint is the only application on this machine that will tell the truth about
 whether these decks open.
 
+### The schema is checked by Microsoft's own validator
+
+A deck whose XML is outside the schema opens in PowerPoint as `[Repaired]`, and the
+checks written by hand here did not catch that. `tests/Conformance/ooxml.php` runs
+Microsoft's Open XML validator — the one the Open XML SDK Productivity Tool uses — over
+every deck the library writes, and the program that does it is in `tools/ooxml-validator/`.
+
+It is a .NET program, so a machine without the SDK skips that test and says what is
+missing; the job that runs it in continuous integration installs it, so the gate cannot
+skip itself there.
+
 ## What a change has to pass
 
 ```
diff --git a/examples/build.php b/examples/build.php
index a2653f6..8b92085 100644
--- a/examples/build.php
+++ b/examples/build.php
@@ -12,22 +12,11 @@
  */
 
 require_once __DIR__ . '/../vendor/autoload.php';
+require_once __DIR__ . '/decks.php';
 
 use MarkdownPresentation\Document\DeckParser;
 use MarkdownPresentation\Render\PresentationRenderer;
 
-/**
- * The sources this script does not convert, and why.
- *
- * Keyed by the file's stem. A deck is here because converting it is the failure it
- * exists to demonstrate, which is the same reason `markdown-word` does not build its
- * `14-rejected.md`: the build would stop, or — worse — would not stop and the gallery
- * would contain a deck that quietly came out wrong.
- */
-const NOT_BUILT = [
-    '10-rejected' => 'converting it is the failure it exists to demonstrate; see examples/README.md',
-];
-
 /** Where the decks, their PDFs and their previews are written. */
 const OUT = __DIR__ . '/out';
 
@@ -37,19 +26,6 @@
 /** The directory a relative image path in a deck resolves against. */
 const SOURCES = __DIR__ . '/markdown';
 
-/**
- * The sources written more than once, and the one line each copy differs in.
- *
- * A theme is a frontmatter key, so the only way to see the three palettes side by side is
- * to write the same deck three times. Varying it here rather than in three files keeps
- * the three decks identical apart from the one line, which is the point of the
- * comparison.
- */
-const VARIANTS = [
-    '03-themes' => ['theme' => ['default', 'corporate-dark', 'minimal']],
-    '11-type-scale' => ['theme' => ['default', 'dense']],
-];
-
 /**
  * What each built deck is for, for the report at the end and for nothing else.
  */
diff --git a/examples/decks.php b/examples/decks.php
new file mode 100644
index 0000000..863e6e7
--- /dev/null
+++ b/examples/decks.php
@@ -0,0 +1,41 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * The decks the examples are written as.
+ *
+ * It is a file of its own because two things need it: the script that writes the decks,
+ * and the test that checks what it wrote against the schema. A list of its own in
+ * either of them would be a second answer to a question this file answers, and the two
+ * would drift — a deck the gallery no longer builds and the gate still checks, or the
+ * other way round, which is the worse of the two: a gate that says less than it says.
+ *
+ * Required rather than included, so that a second caller in the same run does not
+ * declare the constants again.
+ */
+
+/**
+ * The sources this script does not convert, and why.
+ *
+ * Keyed by the file's stem. A deck is here because converting it is the failure it
+ * exists to demonstrate, which is the same reason `markdown-word` does not build its
+ * `14-rejected.md`: the build would stop, or — worse — would not stop and the gallery
+ * would contain a deck that quietly came out wrong.
+ */
+const NOT_BUILT = [
+    '10-rejected' => 'converting it is the failure it exists to demonstrate; see examples/README.md',
+];
+
+/**
+ * The sources written more than once, and the one line each copy differs in.
+ *
+ * A theme is a frontmatter key, so the only way to see the three palettes side by side is
+ * to write the same deck three times. Varying it here rather than in three files keeps
+ * the three decks identical apart from the one line, which is the point of the
+ * comparison.
+ */
+const VARIANTS = [
+    '03-themes' => ['theme' => ['default', 'corporate-dark', 'minimal']],
+    '11-type-scale' => ['theme' => ['default', 'dense']],
+];
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index 383a647..c3c920a 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -15,6 +15,14 @@
         <testsuite name="unit">
             <directory suffix=".php">tests/Unit</directory>
         </testsuite>
+        <!--
+            The decks the library writes, checked against the schema Microsoft's own
+            validator reads. It needs the .NET SDK, which a machine without it does not
+            have, so the test skips itself there.
+        -->
+        <testsuite name="conformance">
+            <directory suffix=".php">tests/Conformance</directory>
+        </testsuite>
         <!--
             Every fenced example in README.md, run. The mechanism is described where
             it is written down — in tests/Support/Doctest.php.
diff --git a/tests/Conformance/ooxml.php b/tests/Conformance/ooxml.php
new file mode 100644
index 0000000..ab65da5
--- /dev/null
+++ b/tests/Conformance/ooxml.php
@@ -0,0 +1,149 @@
+<?php
+
+declare(strict_types=1);
+
+use MarkdownPresentation\Document\DeckParser;
+use MarkdownPresentation\Render\PresentationRenderer;
+use MarkdownPresentation\Render\SvgRasteriser;
+use MarkdownPresentation\Tests\Support\Doctest;
+use MarkdownPresentation\Tests\Support\Scratch;
+
+require_once dirname(__DIR__, 2) . '/examples/decks.php';
+
+/*
+ * Every deck this library writes, checked against the schema Microsoft's own validator
+ * reads — the one the Open XML SDK Productivity Tool uses.
+ *
+ * Nothing in this suite could see that before: the decks were checked against the parts
+ * they carry, and a deck whose XML is outside the schema passes every one of those
+ * checks and opens in PowerPoint as `[Repaired]`. The validator is the oracle, and it is
+ * a program in `tools/ooxml-validator/` rather than a library this package depends on:
+ * nothing that ships with the library needs it, and the suite runs without it.
+ *
+ * A machine with no .NET SDK says what is missing and skips the test. A green tick for a
+ * check that never ran is a check nobody made.
+ */
+
+it('writes decks that are valid OOXML', function () {
+    if (!hasDotnetSdk()) {
+        test()->markTestSkipped(
+            'The .NET SDK is not installed, so the Open XML validator cannot be run. '
+            . 'The job that runs this test in continuous integration installs it.',
+        );
+    }
+
+    $decks = writeExampleDecks();
+
+    [$status, $output] = validateWithOpenXml($decks);
+
+    // Every deck named, because a gate that checked nothing is not a gate. The validator
+    // prints one line per file and how many errors it holds, so a deck missing from the
+    // output is a deck that was not read — which is a failure, not a pass.
+    expect($decks)->not->toBe([]);
+
+    foreach ($decks as $deck) {
+        expect($output)->toContain(basename($deck) . ': 0 error(s)');
+    }
+
+    // The exit code is the tool's own answer, and it is what a caller that reads nothing
+    // else gets: 0 when every deck is clean, 1 when one of them is not, and 2 when the
+    // tool could not run at all. What the tool said is the message, because a failure
+    // here is a failure of the deck and the deck is what has to be looked at.
+    expect($status)->toBe(0, $output);
+});
+
+/**
+ * Whether this machine has the .NET SDK the validator is built with.
+ *
+ * The version rather than the path, because a machine with the runtime and not the SDK
+ * can run a program but not build one, and a path lookup would find the runtime and
+ * answer yes.
+ */
+function hasDotnetSdk(): bool
+{
+    exec('dotnet --version 2>&1', $output, $status);
+
+    return $status === 0;
+}
+
+/**
+ * Every deck the examples are written as, written into the scratch directory.
+ *
+ * The plan of the decks is the one `examples/decks.php` holds, because that is the file
+ * the script that writes them holds it in: a list of its own here would be a second
+ * answer to a question that already has one, and the two would drift. A deck the
+ * gallery no longer builds and the gate still checks is the worse of the two — a gate
+ * that says less than it says.
+ *
+ * @return list<string> The decks written, as paths.
+ */
+function writeExampleDecks(): array
+{
+    $sources = Doctest::root() . '/examples/markdown';
+    $directory = Scratch::directoryPath('decks');
+    $parser = new DeckParser();
+    $written = [];
+
+    foreach (glob($sources . '/*.md') ?: [] as $path) {
+        $stem = basename($path, '.md');
+
+        if (isset(NOT_BUILT[$stem])) {
+            continue;
+        }
+
+        $source = (string) file_get_contents($path);
+
+        // A deck carrying an SVG cannot be written by a build that cannot draw one, and
+        // the reason names the capability rather than the deck: the library refuses that
+        // picture in such a build, so there is no deck to be asked about.
+        if (str_contains($source, '.svg)') && !(new SvgRasteriser())->available()) {
+            test()->markTestSkipped(sprintf(
+                'This build cannot rasterise an SVG, and %s carries one to be drawn.',
+                $stem,
+            ));
+        }
+
+        // A deck written more than once is written once per theme, which the renderer is
+        // told rather than the source: the theme in the source's own frontmatter is the
+        // one the deck asked for, and the copy in the gallery is the same deck in another
+        // theme.
+        $themes = VARIANTS[$stem]['theme'] ?? [null];
+
+        foreach ($themes as $theme) {
+            $renderer = new PresentationRenderer($sources);
+
+            if ($theme !== null) {
+                $renderer->withTheme($theme);
+            }
+
+            $name = $theme === null ? $stem : $stem . '-' . $theme;
+            $target = sprintf('%s/%s.pptx', $directory, $name);
+
+            $renderer->render($parser->parse($source), $target);
+
+            $written[] = $target;
+        }
+    }
+
+    return $written;
+}
+
+/**
+ * What Microsoft's validator makes of the given decks: the exit code and what it said.
+ *
+ * @param list<string> $decks
+ *
+ * @return array{0: int, 1: string}
+ */
+function validateWithOpenXml(array $decks): array
+{
+    $command = sprintf(
+        'dotnet run --project %s -- %s 2>&1',
+        escapeshellarg(Doctest::root() . '/tools/ooxml-validator'),
+        implode(' ', array_map('escapeshellarg', $decks)),
+    );
+
+    exec($command, $output, $status);
+
+    return [$status, implode("\n", $output)];
+}
diff --git a/tests/Readme/examples-decks.php b/tests/Readme/examples-decks.php
index 6aa9a7c..3c8eecc 100644
--- a/tests/Readme/examples-decks.php
+++ b/tests/Readme/examples-decks.php
@@ -155,16 +155,16 @@ function runsOfShape(Pptx $pptx, string $name, int $slide = 1, int $index = 0):
 });
 
 it('builds every deck the page says it builds', function () use ($readme, $root) {
-    $build = (string) file_get_contents($root . '/examples/build.php');
+    $decks = (string) file_get_contents($root . '/examples/decks.php');
     preg_match_all('/`(\d{2}-[a-z-]+)\.md`\s*\|\s*\*\*nothing\*\*/', $readme, $declined);
 
     // A page that says a deck is not built has to be right about it: the reason has to be
-    // in `build.php`, keyed by the stem, or the deck stops being built for a reason nobody
-    // wrote down.
+    // in the plan of the decks, keyed by the stem, or the deck stops being built for a
+    // reason nobody wrote down.
     expect($declined[1])->not->toBe([]);
 
     foreach ($declined[1] as $name) {
-        expect($build)->toContain("'" . $name . "' => '");
+        expect($decks)->toContain("'" . $name . "' => '");
     }
 });
 
diff --git a/tools/ooxml-validator/Program.cs b/tools/ooxml-validator/Program.cs
new file mode 100644
index 0000000..e7d8185
--- /dev/null
+++ b/tools/ooxml-validator/Program.cs
@@ -0,0 +1,110 @@
+// Validates Office Open XML files against the schema, with Microsoft's own
+// validator — the one the Open XML SDK Productivity Tool uses.
+//
+// The exit code is the answer: 0 when every file is clean, 1 when one of them is
+// not, 2 when the tool was asked to do nothing it could do. A gate built on
+// anything else would be a gate on this suite's own opinion of the format rather
+// than on the format.
+
+using DocumentFormat.OpenXml;
+using DocumentFormat.OpenXml.Packaging;
+using DocumentFormat.OpenXml.Validation;
+
+if (args.Length == 0)
+{
+    Console.Error.WriteLine("usage: ooxml-validator [--version <FileFormatVersions>] <file>...");
+    return 2;
+}
+
+// Office2019 rather than the oldest version the SDK knows: the SDK validates
+// against the schema of the version it is given, and a document written for a
+// modern Word should be read as a modern Word would read it. Every file this
+// suite writes has been checked against every version the SDK knows, and the
+// errors are the same at all of them.
+var version = FileFormatVersions.Office2019;
+
+for (var i = 0; i < args.Length; i++)
+{
+    if (args[i] == "--version" && i + 1 < args.Length)
+    {
+        if (!Enum.TryParse<FileFormatVersions>(args[++i], ignoreCase: true, out version))
+        {
+            Console.Error.WriteLine($"not a version the SDK knows: {args[i]}");
+            return 2;
+        }
+
+        continue;
+    }
+
+    if (args[i].StartsWith("--"))
+    {
+        Console.Error.WriteLine($"unknown option: {args[i]}");
+        return 2;
+    }
+}
+
+var files = args.Where(argument => !argument.StartsWith("--")).ToList();
+
+if (files.Count == 0)
+{
+    Console.Error.WriteLine("no files to validate");
+    return 2;
+}
+
+var errors = 0;
+
+foreach (var file in files)
+{
+    if (!File.Exists(file))
+    {
+        Console.Error.WriteLine($"{file}: no such file");
+        errors++;
+        continue;
+    }
+
+    var extension = Path.GetExtension(file).ToLowerInvariant();
+
+    try
+    {
+        errors += extension switch
+        {
+            ".docx" or ".docm" or ".dotx" or ".dotm" => Validate(file, WordprocessingDocument.Open(file, false), version),
+            ".pptx" or ".pptm" or ".potx" or ".potm" => Validate(file, PresentationDocument.Open(file, false), version),
+            _ => Unknown(file),
+        };
+    }
+    catch (Exception exception)
+    {
+        // A file the SDK cannot open is a file the gate cannot pass, so it counts
+        // as an error rather than as a reason to give up.
+        Console.Error.WriteLine($"{file}: could not be opened: {exception.Message}");
+        errors++;
+    }
+}
+
+Console.WriteLine(errors == 0
+    ? $"{files.Count} file(s) checked against {version}: no errors"
+    : $"{files.Count} file(s) checked against {version}: {errors} error(s)");
+
+return errors == 0 ? 0 : 1;
+
+static int Validate(string file, OpenXmlPackage package, FileFormatVersions version)
+{
+    var found = new OpenXmlValidator(version).Validate(package).ToList();
+
+    Console.WriteLine($"{file}: {found.Count} error(s)");
+
+    foreach (var error in found)
+    {
+        Console.WriteLine($"  [{error.ErrorType}] {error.Description}");
+        Console.WriteLine($"    part={error.Part?.Uri} path={error.Path?.XPath}");
+    }
+
+    return found.Count;
+}
+
+static int Unknown(string file)
+{
+    Console.Error.WriteLine($"{file}: not a Word or PowerPoint file");
+    return 1;
+}
diff --git a/tools/ooxml-validator/README.md b/tools/ooxml-validator/README.md
new file mode 100644
index 0000000..e78c508
--- /dev/null
+++ b/tools/ooxml-validator/README.md
@@ -0,0 +1,38 @@
+# The OOXML validator
+
+A console program that opens a `.docx` or a `.pptx` and reports what Microsoft's
+Open XML SDK makes of it. It is the oracle the gate in this repository is measured
+against, so it is not a dependency of the library — nothing the library ships
+depends on it, and the library's own suite does not need it to run.
+
+## Running it
+
+```bash
+dotnet run --project tools/ooxml-validator -- path/to/document.docx
+dotnet run --project tools/ooxml-validator -- --version Office2007 path/to/document.docx
+```
+
+The exit code is the answer: `0` when every file is clean, `1` when one of them is
+not, `2` when there was nothing to check. The errors are printed one per line with
+the part they are in and the path to them, which is what a fix needs to be pointed
+at.
+
+## Why this and not the schema
+
+The schema in ECMA-376 is the definition of the format, and a document that breaks
+it is a document that is not what it claims to be. The SDK reads the same schema,
+and it is the reader the Open XML SDK Productivity Tool — the tool Microsoft's own
+documentation points at — uses. A gate built on it is a gate on the format rather
+than on this suite's opinion of it.
+
+The SDK is also stricter than the schema in a few places, and those places are
+named in the pull requests rather than papered over: `w:tblHeader` and
+`w:bidiVisual` carry an on/off value the SDK reads as `on` or `off` alone, where
+the schema's `ST_OnOff` also allows `1` and `0`.
+
+## Where it runs
+
+The gate that uses it is a job in `.github/workflows/tests.yml`, which installs the
+.NET SDK with `actions/setup-dotnet` before the suite runs. A machine without the
+.NET SDK can still run the rest of the suite; the test that uses this tool skips
+itself there and says why.
diff --git a/tools/ooxml-validator/ooxml-validator.csproj b/tools/ooxml-validator/ooxml-validator.csproj
new file mode 100644
index 0000000..cdcd657
--- /dev/null
+++ b/tools/ooxml-validator/ooxml-validator.csproj
@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <!-- The lowest runtime the tool asks for. A newer runtime runs it unchanged,
+         so the runner's SDK does not have to match the target framework. -->
+    <TargetFramework>net8.0</TargetFramework>
+    <!-- A machine with only a newer runtime can still run this. Without it the
+         runtime refuses the application, and the gate would be a gate on the
+         version of .NET the runner happens to have. -->
+    <RollForward>Major</RollForward>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <RootNamespace>OoxmlValidator</RootNamespace>
+    <AssemblyName>ooxml-validator</AssemblyName>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <!-- The version is pinned rather than ranged, because the validator is the
+         oracle the gate is measured against: a different version of it may find
+         different errors, and a gate whose oracle moves is not a gate. -->
+    <PackageReference Include="DocumentFormat.OpenXml" Version="3.3.0" />
+  </ItemGroup>
+
+</Project>

From 0c7471843f0f5f03dd0eae6f23881a5bfc1a55e1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fabian=20Gra=C3=9Fl?= <mail@fabiangrassl.de>
Date: Fri, 30 Oct 2026 17:26:08 +0100
Subject: [PATCH 3/3] A step that says what the runner has

---
 .github/workflows/tests.yml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index dbd1eb7..1360115 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -121,6 +121,14 @@ jobs:
       - name: Install
         run: composer install --prefer-dist --no-interaction --no-progress
 
+      - name: What the runner has
+        run: |
+          php -r 'var_dump(extension_loaded("imagick"));'
+          php -r 'print_r(Imagick::queryFormats("*SVG*"));'
+          convert -list format 2>/dev/null | grep -i svg || echo "no convert"
+          convert -list delegate 2>/dev/null | grep -i svg || echo "no delegate"
+          fc-list 2>/dev/null | head -3 || echo "no fonts"
+
       - name: The decks are valid OOXML
         run: vendor/bin/pest --testsuite=conformance --fail-on-skipped