From 5508e9ced1259bdde3868e98e3f9560d8847bea8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Laurent=20Tr=C3=A9guier?= <laurent@treguier.org>
Date: Wed, 14 Nov 2018 17:32:27 +0100
Subject: [PATCH] Fix #407 - `dub run dfmt` keeps building dfmt anew each time

---
 dub.json  |  2 +-
 dubhash.d | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 dubhash.d

diff --git a/dub.json b/dub.json
index f48228a..f51d6ce 100644
--- a/dub.json
+++ b/dub.json
@@ -15,6 +15,6 @@
         "built_with_dub"
     ],
     "preGenerateCommands" : [
-      "rdmd --eval=\"auto dir=environment.get(\\\"DUB_PACKAGE_DIR\\\"); dir.buildPath(\\\"bin\\\").mkdirRecurse; auto gitVer = (\\\"git -C \\\"~dir~\\\" describe --tags\\\").executeShell; (gitVer.status == 0 ? gitVer.output.strip : \\\"v\\\" ~ dir.dirName.baseName.findSplitAfter(environment.get(\\\"DUB_ROOT_PACKAGE\\\")~\\\"-\\\")[1]).ifThrown(\\\"0.0.0\\\").chain(newline).to!string.toFile(dir.buildPath(\\\"bin\\\", \\\"dubhash.txt\\\"));\""
+      "rdmd dubhash.d"
     ]
 }
diff --git a/dubhash.d b/dubhash.d
new file mode 100644
index 0000000..7f11ca5
--- /dev/null
+++ b/dubhash.d
@@ -0,0 +1,23 @@
+import std.algorithm;
+import std.ascii;
+import std.conv;
+import std.exception;
+import std.file;
+import std.path;
+import std.process;
+import std.range;
+import std.string;
+
+void main()
+{
+    auto dir = environment.get("DUB_PACKAGE_DIR");
+    auto hashFile = dir.buildPath("bin", "dubhash.txt");
+    auto gitVer = executeShell("git -C " ~ dir ~ " describe --tags");
+    auto ver = (gitVer.status == 0 ? gitVer.output.strip
+            : "v" ~ dir.dirName.baseName.findSplitAfter(
+                environment.get("DUB_ROOT_PACKAGE") ~ "-")[1]).ifThrown("0.0.0")
+        .chain(newline).to!string.strip;
+    dir.buildPath("bin").mkdirRecurse;
+    if (!hashFile.exists || ver != hashFile.readText.strip)
+        hashFile.write(ver);
+}