Description of the problem:

Variables set by --action_env are not forwarded through tools dependency of a rule. To generate test example, paste following lines into terminal:

mkdir test
cd test
touch WORKSPACE
touch tool.sh
chmod +x tool.sh
cat > BUILD << EOF
genrule(
    name = "rule1",
    srcs = [],
    outs = ["out1.c"],
    cmd = "bash -c 'echo RULE1:TESTVAR=\$\$TESTVAR'; exit 1",
)

sh_binary(
    name = "tool",
    srcs = ["tool.sh"],
    # srcs = [":rule1"],
    data = [":rule1"],
)

genrule(
    name = "rule2",
    srcs = [],
    outs = ["out2.c"],
    cmd = "",
    tools = [":tool"],
)

genrule(
    name = "rule3",
    srcs = [],
    outs = ["out3.c"],
    cmd = "",
    tools = [":rule1"],
)

genrule(
    name = "rule4",
    srcs = [":rule1"],
    outs = ["out4.c"],
    cmd = "",
)

cc_binary(
    name = "main",
    srcs = [
        # ":rule1",
        # ":rule2",
        # ":rule3",
        # ":rule4",
    ],
    data = [
        # ":rule1",
        ":rule2",
        # ":rule3",
        # ":rule4",
        # ":tool",
    ],
)
EOF
bazel build :main --action_env TESTVAR=hello

outputs

RULE1:TESTVAR=

however depending on what is uncommented, i.e., ":rule1",, ":rule2",, ":rule3",, ":rule4",, ":tool", at the end of BUILD, bazel may output also

RULE1:TESTVAR=hello

rule1 gives RULE1:TESTVAR=hello - rule1 is directly referenced
rule2 and rule3 gives RULE1:TESTVAR= - rule1 is referenced via tools option
rule4 and tool again gives RULE1:TESTVAR=hello - rule1 is referenced via middleman

If the rule1 is referenced from the "tool" and from another rule as a dependency, it may be randomly executed with different environment set for each run. Is this the expected behaviour?

A consistent behaviour is obtained when exporting the environment variable into bazel environment, i.e.,

export TESTVAR="hello world!"
bazel shutdown
bazel build :main

NOTE: in case there is a linking error, execute the last command (bazel build ...) once more.
NOTE2: if more than one rule dependency is uncommented, it may randomly output both results, execute multiple times to verify, e.g.,

for i in 1 2 3 4 5; do bazel build :main --action_env TESTVAR=hello 2> /dev/null | grep TESTVAR ; done

Environment info

• Operating System: macOS, Linux

• Bazel version: release 0.7.0, release 0.5.4