错误描述：
$ git pull origin alpha
From https://github.com/shirley-wu/HeartTrace
* branch alpha -> FETCH_HEAD
error: The following untracked working tree files would be overwritten by merge:
.gradle/4.4/fileChanges/last-build.bin
.gradle/4.4/fileHashes/fileHashes.bin
.gradle/4.4/fileHashes/fileHashes.lock
.gradle/4.4/fileHashes/resourceHashesCache.bin
.gradle/4.4/taskHistory/taskHistory.bin
.gradle/4.4/taskHistory/taskHistory.lock
.gradle/buildOutputCleanup/buildOutputCleanup.lock
.gradle/buildOutputCleanup/cache.properties
.gradle/buildOutputCleanup/outputFiles.bin
.idea/gradle.xml
.idea/workspace.xml
app/app.iml
app/build/generated/res/pngs/debug/drawable-anydpi-v21/ic_launcher_background.xml
app/build/generated/res/pngs/debug/drawable-hdpi/ic_launcher_background.png
app/build/generated/res/pngs/debug/drawable-ldpi/ic_launcher_background.png
app/build/generated/res/pngs/debug/drawable-mdpi/ic_launcher_background.png
app/build/generated/res/pngs/debug/drawable-xhdpi/ic_launcher_background.png
app/build/generated/res/pngs/debug/drawable-xxhdpi/ic_launcher_background.png
app/build/generated/res/pngs/debug/drawable-xxxhdpi/ic_launcher_background.png
app/build/generated/source/buildConfig/debug/com/example/dell/diary/BuildConfig.java
app/build/generated/source/r/debug/android/arch/lifecycle/R.java
app/build/generated/source/r/debug/android/support/compat/R.java
app/build/generated/source/r/debug/android/support/constraint/R.java
app/build/generated/source/r/debug/android/support/coreui/R.java
app/build/generated/source/r/debug/android/support/coreutils/R.java
app/build/generated/source/r/debug/android/support/design/R.java
app/build/generated/source/r/debug/android/support/fragment/R.java
app/build/generated/source/r/debug/android/support/graphics/drawable/R.java
app/build/generated/source/r/debug/android/support/graphics/drawable/animated/R.java
app/build/generated/source/r/debug/android/support/mediacompat/R.java
app/build/generated/source/r/debug/android/support/transition/R.java
app/build/generated/source/r/debug/android/support/v4/R.java
app/build/generated/source/r/debug/android/support/v7/appcompat/R.java
app/build/generated/source/r/debug/android/support/v7/cardview/R.java
app/build/generated/source/r/debug/android/support/v7/recyclerview/R.java
app/build/generated/source/r/debug/com/bigkoo/pickerview/R.java
app/build/generated/source/r/debug/com/borax12/materialdaterangepicker/R.java
app/build/generated/source/r/debug/com/contrarywind/view/R.java
app/build/generated/source/r/debug/com/example/dell/diary/R.java
app/build/generated/source/r/debug/com/google/android/gms/R.java
app/build/generated/source/r/debug/com/google/android/gms/appindexing/R.java
app/build/generated/source/r/debug/com/google/android/gms/base/R.java
app/build/generated/source/r/debug/com/google/android/gms/tasks/R.java
app/build/generated/source/r/debug/com/google/firebase/R.java
app/build/generated/source/r/debug/com/prolificinteractive/materialcalendarview/R.java
app/build/generated/source/r/debug/de/hdodenhof/circleimageview/R.java
app/build/generated/source/r/debug/net/sqlcipher/R.java
app/build/generated/source/r/debug/org/adw/library/widgets/discreteseekbar/R.java
app/build/intermediates/blame/res/debug/multi-v2/values-af.json
app/build/intermediates/blame/res/debug/multi-v2/values-am.json
app/build/intermediates/blame/res/debug/multi-v2/values-ar.json
app/build/intermediates/blame/res/debug/multi-v2/values-az.json
app/build/intermediates/blame/res/debug/multi-v2/values-b+sr+Latn.json
app/build/intermediates/blame/res/debug/multi-v2/values-be.json
app/build/intermediates/blame/res/debug/multi-v2/values-bg.json
app/build/intermediates/blame/res/debug/multi-v2/values-bn.json
app/build/intermediates/blame/res/debug/multi-v2/values-bs.json
app/build/intermediates/blame/res/debug/multi-v2/values-ca.json
app/build/intermediates/blame/res/debug/multi-v2/values-cs.json
app/build/intermediates/blame/res/debug/multi-v2/values-da.json
app/build/intermediates/blame/res/debug/multi-v2/values-de.json
app/build/intermediates/blame/res/debug/multi-v2/values-el.json
app/build/intermediates/blame/res/debug/mul
Aborting
解决方法：
git clean -d -fx
git pull
手动merge
git add .
git commit -m "description"
原文地址：https://www.cnblogs.com/ustckx16/p/9251064.html