Multi Path Artifact Upload + Exclude Character Support (#94)

* Support for multi path upload

* Update README

* Fix tests

* Actually fix tests

* PR feedback

* Fix

* Apply suggestions from code review

Co-authored-by: Alberto Gimeno <gimenete@users.noreply.github.com>

* Fix more tests

Co-authored-by: Alberto Gimeno <gimenete@users.noreply.github.com>

src/search.ts

@@ -1,5 +1,6 @@
 import * as glob from '@actions/glob'
-import {debug} from '@actions/core'
+import * as path from 'path'
+import {debug, info} from '@actions/core'
 import {lstatSync} from 'fs'
 import {dirname} from 'path'
 
@@ -16,6 +17,65 @@ function getDefaultGlobOptions(): glob.GlobOptions {
   }
 }
 
+/**
+ * If multiple paths are specific, the least common ancestor (LCA) of the search paths is used as
+ * the delimiter to control the directory structure for the artifact. This function returns the LCA
+ * when given an array of search paths
+ *
+ * Example 1: The patterns `/foo/` and `/bar/` returns `/`
+ *
+ * Example 2: The patterns `~/foo/bar/*` and `~/foo/voo/two/*` and `~/foo/mo/` returns `~/foo`
+ */
+function getMultiPathLCA(searchPaths: string[]): string {
+  if (searchPaths.length < 2) {
+    throw new Error('At least two search paths must be provided')
+  }
+
+  const commonPaths = new Array<string>()
+  const splitPaths = new Array<string[]>()
+  let smallestPathLength = Number.MAX_SAFE_INTEGER
+
+  // split each of the search paths using the platform specific separator
+  for (const searchPath of searchPaths) {
+    debug(`Using search path ${searchPath}`)
+
+    const splitSearchPath = path.normalize(searchPath).split(path.sep)
+
+    // keep track of the smallest path length so that we don't accidentally later go out of bounds
+    smallestPathLength = Math.min(smallestPathLength, splitSearchPath.length)
+    splitPaths.push(splitSearchPath)
+  }
+
+  // on Unix-like file systems, the file separator exists at the beginning of the file path, make sure to preserve it
+  if (searchPaths[0].startsWith(path.sep)) {
+    commonPaths.push(path.sep)
+  }
+
+  let splitIndex = 0
+  // function to check if the paths are the same at a specific index
+  function isPathTheSame(): boolean {
+    const compare = splitPaths[0][splitIndex]
+    for (let i = 1; i < splitPaths.length; i++) {
+      if (compare !== splitPaths[i][splitIndex]) {
+        // a non-common index has been reached
+        return false
+      }
+    }
+    return true
+  }
+
+  // Loop over all the search paths until there is a non-common ancestor or we go out of bounds
+  while (splitIndex < smallestPathLength) {
+    if (!isPathTheSame()) {
+      break
+    }
+    // if all are the same, add to the end result & increment the index
+    commonPaths.push(splitPaths[0][splitIndex])
+    splitIndex++
+  }
+  return path.join(...commonPaths)
+}
+
 export async function findFilesToUpload(
   searchPath: string,
   globOptions?: glob.GlobOptions
@@ -42,13 +102,22 @@ export async function findFilesToUpload(
     }
   }
 
-  /*
-    Only a single search pattern is being included so only 1 searchResult is expected. In the future if multiple search patterns are
-    simultaneously supported this will change
-  */
+  // Calculate the root directory for the artifact using the search paths that were utilized
   const searchPaths: string[] = globber.getSearchPaths()
+
   if (searchPaths.length > 1) {
-    throw new Error('Only 1 search path should be returned')
+    info(
+      `Multiple search paths detected. Calculating the least common ancestor of all paths`
+    )
+    const lcaSearchPath = getMultiPathLCA(searchPaths)
+    info(
+      `The least common ancestor is ${lcaSearchPath}. This will be the root directory of the artifact`
+    )
+
+    return {
+      filesToUpload: searchResults,
+      rootDirectory: lcaSearchPath
+    }
   }
 
   /*