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| author | Bartosz Nitka <niteria@gmail.com> | 2015-10-27 10:19:48 -0500 |
|---|---|---|
| committer | Austin Seipp <austin@well-typed.com> | 2015-10-27 10:19:54 -0500 |
| commit | ffcdd84f86727c1621be0a0e522eb6a3a64e479f (patch) | |
| tree | 248f97aeb7af6185a78ebeb0bf9baea65681953e /testsuite/tests/determinism | |
| parent | dc13467347fa9bf9e1a70389a2eccd9bd4853d21 (diff) | |
| download | haskell-ffcdd84f86727c1621be0a0e522eb6a3a64e479f.tar.gz | |
Sort field labels before fingerprint hashing
`fsEnvElts :: FastStringEnv a -> [a]` returns a list of `[a]` in the order of
`Unique`s which is arbitrary. In this case it gives a list of record fields in
arbitrary order, from which we then extract the field labels to contribute to
the record fingerprint. The arbitrary ordering of field labels introduces
unnecessary nondeterminism in interface files as demonstrated by the test case.
We sort `FastString` here. It's safe, because the only way that the `Unique`
associated with the `FastString` is used in comparison is for equality. If the
`Unique`s are different it fallbacks to comparing the actual `ByteString`.
Reviewed By: ezyang, thomie, bgamari, austin
Differential Revision: https://phabricator.haskell.org/D1373
GHC Trac Issues: #4012
Diffstat (limited to 'testsuite/tests/determinism')
| -rw-r--r-- | testsuite/tests/determinism/determ002/A.hs | 10 | ||||
| -rw-r--r-- | testsuite/tests/determinism/determ002/Makefile | 13 | ||||
| -rw-r--r-- | testsuite/tests/determinism/determ002/all.T | 4 | ||||
| -rw-r--r-- | testsuite/tests/determinism/determ002/determ002.stderr | 0 | ||||
| -rw-r--r-- | testsuite/tests/determinism/determ002/determ002.stdout | 2 |
5 files changed, 29 insertions, 0 deletions
diff --git a/testsuite/tests/determinism/determ002/A.hs b/testsuite/tests/determinism/determ002/A.hs new file mode 100644 index 0000000000..9a88f2c319 --- /dev/null +++ b/testsuite/tests/determinism/determ002/A.hs @@ -0,0 +1,10 @@ +module A where + +-- This is a repro for the issue where to fingerprint a record, field labels +-- were pulled from FastStringEnv in the order of Uniques which are known +-- to have arbitrary order - see Note [Unique Determinism] in Unique. + +data B = C + { e :: () + , d :: () + } diff --git a/testsuite/tests/determinism/determ002/Makefile b/testsuite/tests/determinism/determ002/Makefile new file mode 100644 index 0000000000..d94a1c22ec --- /dev/null +++ b/testsuite/tests/determinism/determ002/Makefile @@ -0,0 +1,13 @@ +TOP=../../.. +include $(TOP)/mk/boilerplate.mk +include $(TOP)/mk/test.mk + +TEST_HC_OPTS_NO_RECOMP = $(filter-out -fforce-recomp,$(TEST_HC_OPTS)) + +determ002: + $(RM) A.hi A.o + '$(TEST_HC)' $(TEST_HC_OPTS_NO_RECOMP) A.hs + $(CP) A.hi A.old.hi + $(RM) A.o + '$(TEST_HC)' $(TEST_HC_OPTS_NO_RECOMP) A.hs + diff A.hi A.old.hi diff --git a/testsuite/tests/determinism/determ002/all.T b/testsuite/tests/determinism/determ002/all.T new file mode 100644 index 0000000000..9bfd05db00 --- /dev/null +++ b/testsuite/tests/determinism/determ002/all.T @@ -0,0 +1,4 @@ +test('determ002', + extra_clean(['A.o', 'A.hi', 'A.old.hi']), + run_command, + ['$MAKE -s --no-print-directory determ002']) diff --git a/testsuite/tests/determinism/determ002/determ002.stderr b/testsuite/tests/determinism/determ002/determ002.stderr new file mode 100644 index 0000000000..e69de29bb2 --- /dev/null +++ b/testsuite/tests/determinism/determ002/determ002.stderr diff --git a/testsuite/tests/determinism/determ002/determ002.stdout b/testsuite/tests/determinism/determ002/determ002.stdout new file mode 100644 index 0000000000..60c2bc368d --- /dev/null +++ b/testsuite/tests/determinism/determ002/determ002.stdout @@ -0,0 +1,2 @@ +[1 of 1] Compiling A ( A.hs, A.o ) +[1 of 1] Compiling A ( A.hs, A.o ) |