Error if none of the tasks passed to CLI were found (#3828)

Previously, a `validate` method asserted that tasks passed to the
CLI exist. We removed this validation for the purpose of lazily
loading turbo.jsons. Bringing back this feature here.

cli/integration_tests/basic_monorepo/dry_run.t

@@ -102,12 +102,8 @@ Check my-app#build output
     }
   }
 
-$ Non-existent tasks don't throw an error
+Tasks that don't exist throw an error
   $ ${TURBO} run doesnotexist --dry=json
-  {
-    "packages": [
-      "my-app",
-      "util"
-    ],
-    "tasks": []
-  }
+   ERROR  run failed: error preparing engine: Could not find the following tasks in project: doesnotexist
+  Turbo error: error preparing engine: Could not find the following tasks in project: doesnotexist
+  [1]

cli/integration_tests/basic_monorepo/run.t

@@ -2,15 +2,20 @@ Setup
   $ . ${TESTDIR}/../setup.sh
   $ . ${TESTDIR}/setup.sh $(pwd)
 
-$ running non-existent tasks works
+# Running non-existent tasks errors
   $ ${TURBO} run doesnotexist
-  \xe2\x80\xa2 Packages in scope: my-app, util (esc)
-  \xe2\x80\xa2 Running doesnotexist in 2 packages (esc)
-  \xe2\x80\xa2 Remote caching disabled (esc)
-
-  No tasks were executed as part of this run.
-
-   Tasks:    0 successful, 0 total
-  Cached:    0 cached, 0 total
-    Time:\s*[\.0-9]+m?s  (re)
-
+   ERROR  run failed: error preparing engine: Could not find the following tasks in project: doesnotexist
+  Turbo error: error preparing engine: Could not find the following tasks in project: doesnotexist
+  [1]
+
+# Multiple non-existent tasks also error
+  $ ${TURBO} run doesnotexist alsono
+   ERROR  run failed: error preparing engine: Could not find the following tasks in project: alsono, doesnotexist
+  Turbo error: error preparing engine: Could not find the following tasks in project: alsono, doesnotexist
+  [1]
+
+# One good and one bad task does not error
+  $ ${TURBO} run build doesnotexist
+   ERROR  run failed: error preparing engine: Could not find the following tasks in project: doesnotexist
+  Turbo error: error preparing engine: Could not find the following tasks in project: doesnotexist
+  [1]

cli/internal/core/engine.go

@@ -158,6 +158,9 @@ func (e *Engine) Prepare(options *EngineBuildingOptions) error {
 
 	traversalQueue := []string{}
 
+	// get a set of taskNames passed in. we'll remove the ones that have a definition
+	missing := util.SetFromStrings(taskNames)
+
 	// Get a list of entry points into our TaskGraph.
 	// We do this by taking the input taskNames, and pkgs
 	// and creating a queue of taskIDs that we can traverse and gather dependencies from.
@@ -180,14 +183,23 @@ func (e *Engine) Prepare(options *EngineBuildingOptions) error {
 
 					return err
 				}
-
+				// delete taskName if it was found
+				missing.Delete(taskName)
 				traversalQueue = append(traversalQueue, taskID)
 			}
 		}
 	}
 
 	visited := make(util.Set)
 
+	// validate that all tasks passed were found
+	missingList := missing.UnsafeListOfStrings()
+	sort.Strings(missingList)
+
+	if len(missingList) > 0 {
+		return fmt.Errorf("Could not find the following tasks in project: %s", strings.Join(missingList, ", "))
+	}
+
 	// Things get appended to traversalQueue inside this loop, so we use the len() check instead of range.
 	for len(traversalQueue) > 0 {
 		// pop off the first item from the traversalQueue