diff --git a/pkgs/applications/virtualization/gvisor/default.nix b/pkgs/applications/virtualization/gvisor/default.nix
index 2d99fb3bf57..3d0ae35f560 100644
--- a/pkgs/applications/virtualization/gvisor/default.nix
+++ b/pkgs/applications/virtualization/gvisor/default.nix
@@ -76,7 +76,7 @@ in buildBazelPackage rec {
       rm -f "$bazelOut"/java.log "$bazelOut"/java.log.*
     '';
 
-    sha256 = "122qk6iv8hd7g2a84y9aqqhij4r0m47vpxzbqhhh6k5livc73qd6";
+    sha256 = "1bn7nhv5pag8fdm8l8nvgg3fzvhpy2yv9yl2slrb16lckxzha3v6";
   };
 
   buildAttrs = {
diff --git a/pkgs/build-support/build-bazel-package/default.nix b/pkgs/build-support/build-bazel-package/default.nix
index 058f42aa8d5..47c72bf9260 100644
--- a/pkgs/build-support/build-bazel-package/default.nix
+++ b/pkgs/build-support/build-bazel-package/default.nix
@@ -122,6 +122,8 @@ in stdenv.mkDerivation (fBuildAttrs // {
 
       cp -r $bazelOut/external $out
 
+      echo '${bazel.name}' > $out/.nix-bazel-version
+
       runHook postInstall
     '';
 
@@ -143,6 +145,14 @@ in stdenv.mkDerivation (fBuildAttrs // {
 
   preConfigure = ''
     mkdir -p "$bazelOut"
+
+    test "${bazel.name}" = "$(<$deps/.nix-bazel-version)" || {
+      echo "fixed output derivation was built for a different bazel version" >&2
+      echo "     got: $(<$deps/.nix-bazel-version)" >&2
+      echo "expected: ${bazel.name}" >&2
+      exit 1
+    }
+
     cp -r $deps $bazelOut/external
     chmod -R +w $bazelOut
     find $bazelOut -type l | while read symlink; do
diff --git a/pkgs/development/python-modules/dm-sonnet/default.nix b/pkgs/development/python-modules/dm-sonnet/default.nix
index 4ce61680f03..603d900b810 100644
--- a/pkgs/development/python-modules/dm-sonnet/default.nix
+++ b/pkgs/development/python-modules/dm-sonnet/default.nix
@@ -36,7 +36,7 @@ let
     bazelTarget = ":install";
 
     fetchAttrs = {
-      sha256 = "0mxma7jajm42v1hv6agl909xra0azihj588032ivhlmmh403x6wg";
+      sha256 = "0wb2gh9ji8bgq4s9ci9x017dybxqzjhncpw33b1wjksm2yhbkvlz";
     };
 
     bazelFlags = [
diff --git a/pkgs/development/python-modules/tensorflow-estimator/1_15_1.nix b/pkgs/development/python-modules/tensorflow-estimator/1_15_1.nix
new file mode 100644
index 00000000000..39c667357c8
--- /dev/null
+++ b/pkgs/development/python-modules/tensorflow-estimator/1_15_1.nix
@@ -0,0 +1,27 @@
+{ stdenv, fetchPypi, buildPythonPackage
+, numpy
+, absl-py
+, mock
+}:
+
+buildPythonPackage rec {
+  pname = "tensorflow-estimator";
+  version = "1.15.1";
+  format = "wheel";
+
+  src = fetchPypi {
+    pname = "tensorflow_estimator";
+    inherit version format;
+    sha256 = "1fc61wmc0w22frs79j2x4g6wnv5g21xc6rix1g4bsvy9qfvvylw8";
+  };
+
+  propagatedBuildInputs = [ mock numpy absl-py ];
+
+  meta = with stdenv.lib; {
+    description = "TensorFlow Estimator is a high-level API that encapsulates model training, evaluation, prediction, and exporting.";
+    homepage = http://tensorflow.org;
+    license = licenses.asl20;
+    maintainers = with maintainers; [ jyp ];
+  };
+}
+
diff --git a/pkgs/development/python-modules/tensorflow-probability/default.nix b/pkgs/development/python-modules/tensorflow-probability/default.nix
index b585ab4f81b..99a3a978a4e 100644
--- a/pkgs/development/python-modules/tensorflow-probability/default.nix
+++ b/pkgs/development/python-modules/tensorflow-probability/default.nix
@@ -42,7 +42,7 @@ let
     bazelTarget = ":pip_pkg";
 
     fetchAttrs = {
-      sha256 = "0sjjj9z1dhilhpc8pq4154czrb79z9cm044jvn75kxcjv6v5l2m5";
+      sha256 = "0135nxxvkmjzpd80r1g9fdkk9h62g0xlvp32g5zgk0hkma5kq0bx";
     };
 
     buildAttrs = {
diff --git a/pkgs/development/python-modules/tensorflow/default.nix b/pkgs/development/python-modules/tensorflow/default.nix
index 9e5acca4749..cdf659a74dc 100644
--- a/pkgs/development/python-modules/tensorflow/default.nix
+++ b/pkgs/development/python-modules/tensorflow/default.nix
@@ -7,7 +7,7 @@
 , future, setuptools, wheel, keras-preprocessing, keras-applications, google-pasta
 , functools32
 , opt-einsum
-, termcolor, grpcio, six, wrapt, protobuf, tensorflow-estimator
+, termcolor, grpcio, six, wrapt, protobuf, tensorflow-estimator_1_15_1
 # Common deps
 , git, swig, which, binutils, glibcLocales, cython
 # Common libraries
@@ -296,10 +296,12 @@ let
       TF_SYSTEM_LIBS = null;
 
       # cudaSupport causes fetch of ncclArchive, resulting in different hashes
+      # FIXME: can't (re)produce this output with current bazel.
+      # FIXME: build log: https://gist.github.com/andir/eff3e9c8eda5b56c8ea84903aed9cc35
       sha256 = if cudaSupport then
-        "1p544yk7jcspgc4qr4amw11ds16c2an5yxvagx5pmwawz0s083pf"
+        "0gyhjvzshgj59mbns8njlfl9qpz4sdg4j0xs2dva0w2nql7cr7im"
       else
-        "1dqbw3k3avqiy9xpgs44l6z65ab5rjjlxwig8z7gcl7fw9h6sbq9";
+        "04jvg3mc2si4xdbszc1vnw1rmf22p7snbjphmnklp7bc39jxkcrz";
     };
 
     buildAttrs = {
@@ -374,7 +376,7 @@ in buildPythonPackage {
     numpy
     six
     protobuf
-    tensorflow-estimator
+    tensorflow-estimator_1_15_1
     termcolor
     wrapt
     grpcio
diff --git a/pkgs/development/tools/bazel-watcher/default.nix b/pkgs/development/tools/bazel-watcher/default.nix
index 62ecc47b17b..29276fb6bfb 100644
--- a/pkgs/development/tools/bazel-watcher/default.nix
+++ b/pkgs/development/tools/bazel-watcher/default.nix
@@ -62,7 +62,7 @@ buildBazelPackage rec {
       sed -e '/^FILE:@bazel_gazelle_go_repository_tools.*/d' -i $bazelOut/external/\@*.marker
     '';
 
-    sha256 = "0g2y283glx2ykxxqc3vsg520a6s2w5d937wndhgpfajc5yjgiz43";
+    sha256 = "0cmj186n2y1g9kkdhcivmh2qvigvpnbp03m575b7hgsxi1cp3ssj";
   };
 
   buildAttrs = {
diff --git a/pkgs/development/tools/build-managers/bazel/bazel-remote/default.nix b/pkgs/development/tools/build-managers/bazel/bazel-remote/default.nix
index ffdeb01c2bb..88dd7f45ab5 100644
--- a/pkgs/development/tools/build-managers/bazel/bazel-remote/default.nix
+++ b/pkgs/development/tools/build-managers/bazel/bazel-remote/default.nix
@@ -64,7 +64,7 @@ buildBazelPackage rec {
       sed -e '/^FILE:@bazel_gazelle_go_repository_tools.*/d' -i $bazelOut/external/\@*.marker
     '';
 
-    sha256 = "1n66hg1w5jv2rc8q4sjlaf0agvxr713aa40mbkhgjv57x9j7bgn0";
+    sha256 = "0lnwc7ya6sjlx6jk5dwws166vli1lzdfc256f9g6dy1fci3sc17y";
   };
 
   buildAttrs = {
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 9516ce18dbc..74f2112f0ec 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -6659,6 +6659,7 @@ in {
   zerobin = callPackage ../development/python-modules/zerobin { };
 
   tensorflow-estimator = callPackage ../development/python-modules/tensorflow-estimator { };
+  tensorflow-estimator_1_15_1 = callPackage ../development/python-modules/tensorflow-estimator/1_15_1.nix { };
 
   tensorflow-probability = callPackage ../development/python-modules/tensorflow-probability { };