From 91077132615ecab9df4afc2ea8308d25dd2d50f8 Mon Sep 17 00:00:00 2001
From: Kris Kaczor <krzkaczor@gmail.com>
Date: Mon, 24 Jul 2023 11:09:10 +0400
Subject: [PATCH] Fix the `lowestCommonPath` function,  #772 (#858)

Co-authored-by: Alex Dupre <ale@FreeBSD.org>
---
 .changeset/ten-pants-learn.md                      |  5 +++++
 .../typechain/src/utils/files/lowestCommonPath.ts  | 14 +++++++++++++-
 .../test/utils/files/lowestCommonPath.test.ts      | 10 ++++++++++
 3 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/ten-pants-learn.md

diff --git a/.changeset/ten-pants-learn.md b/.changeset/ten-pants-learn.md
new file mode 100644
index 000000000..7bf5e117a
--- /dev/null
+++ b/.changeset/ten-pants-learn.md
@@ -0,0 +1,5 @@
+---
+'typechain': patch
+---
+
+Fix the detection of inputs root in some specific scenarios
diff --git a/packages/typechain/src/utils/files/lowestCommonPath.ts b/packages/typechain/src/utils/files/lowestCommonPath.ts
index 4c3bcdbf9..c660eb790 100644
--- a/packages/typechain/src/utils/files/lowestCommonPath.ts
+++ b/packages/typechain/src/utils/files/lowestCommonPath.ts
@@ -1,5 +1,17 @@
 export function lowestCommonPath(paths: string[]) {
   const pathParts = paths.map((path) => path.split(/[\\/]/))
-  const commonParts = pathParts[0].filter((part, index) => pathParts.every((parts) => parts[index] === part))
+  const commonParts = [] as string[]
+  const maxParts = Math.min.apply(
+    null,
+    pathParts.map((p) => p.length),
+  )
+  for (let i = 0; i < maxParts; i++) {
+    const part = pathParts[0][i]
+    if (pathParts.slice(1).every((otherPath) => otherPath[i] === part)) {
+      commonParts.push(part)
+    } else {
+      break
+    }
+  }
   return commonParts.join('/')
 }
diff --git a/packages/typechain/test/utils/files/lowestCommonPath.test.ts b/packages/typechain/test/utils/files/lowestCommonPath.test.ts
index 0c4d190cb..21ffe88da 100644
--- a/packages/typechain/test/utils/files/lowestCommonPath.test.ts
+++ b/packages/typechain/test/utils/files/lowestCommonPath.test.ts
@@ -18,6 +18,16 @@ describe(lowestCommonPath.name, () => {
     expect(actual).toEqual('/TypeChain/contracts/compiled')
   })
 
+  it('stops at first different sub-path', () => {
+    const paths = [
+      '/TypeChain/contracts/v0.6.4/interfaces/Payable.abi',
+      '/TypeChain/contracts/v0.8.9/interfaces/Rarity.abi',
+    ]
+
+    const actual = lowestCommonPath(paths)
+    expect(actual).toEqual('/TypeChain/contracts')
+  })
+
   it('works for Windows paths', () => {
     const paths = [
       'D:/workspace/TypeChain/packages/hardhat/test/fixture-projects/hardhat-project/artifacts/contracts/EdgeCases.sol/EdgeCases.json',