Commit Graph

462 Commits

Author SHA1 Message Date
Todd Gamblin
4af6303086 copyright: update copyright dates for 2020 (#14328) 2019-12-30 22:36:56 -08:00
Todd Gamblin
8e8235043d package_prefs: move class-level cache to PackagePref instance
`PackagePrefs` has had a class-level cache of data from `packages.yaml` for
a long time, but it complicates testing and leads to subtle errors,
especially now that we frequently manipulate custom config scopes and
environments.

Moving the cache to instance-level doesn't slow down concretization or
the test suite, and it just caches for the life of a `PackagePrefs`
instance (i.e., for a single cocncretization) so we don't need to worry
about global state anymore.

- [x] Remove class-level caches from `PackagePrefs`
- [x] Add a cached _spec_order object on each `PackagePrefs` instance
- [x] Remove all calls to `PackagePrefs.clear_caches()`
2019-12-30 13:01:31 -08:00
Todd Gamblin
2dafeaf819 bugfix: colify_table should not revert to 1 column for non-tty (#14307)
Commands like `spack blame` were printig poorly when redirected to files,
as colify reverts to a single column when redirected.  This works for
list data but not tables.

- [x] Force a table by always passing `tty=True` from `colify_table()`
2019-12-28 11:26:31 -08:00
Massimiliano Culpo
d333e14721 tests: check min required python version with vermin (#14289)
This commit removes the `python_version.py` unit test module
and the vendored dependencies `pyqver2.py` and `pyqver3.py`.
It substitutes them with an equivalent check done using
`vermin` that is run as a separate workflow via Github Actions.

This allows us to delete 2 vendored dependencies that are unmaintained
and substitutes them with a maintained tool.

Also, updates the list of vendored dependencies.
2019-12-24 09:28:33 -08:00
t-karatsu
1e2c9d960c a64fx: fix typo in GCC flags (#14286) 2019-12-24 17:45:03 +01:00
Todd Gamblin
9b90d7e801 performance: reduce system calls required for remove_dead_links
`os.path.exists()` will report False if the target of a symlink doesn't
exist, so we can avoid a costly call to realpath here.
2019-12-23 18:36:56 -08:00
Todd Gamblin
6c9467e8c6 lock transactions: avoid redundant reading in write transactions
Our `LockTransaction` class was reading overly aggressively.  In cases
like this:

```
1  with spack.store.db.read_transaction():
2    with spack.store.db.write_transaction():
3      ...
```

The `ReadTransaction` on line 1 would read in the DB, but the
WriteTransaction on line 2 would read in the DB *again*, even though we
had a read lock the whole time.  `WriteTransaction`s were only
considering nested writes to decide when to read, but they didn't know
when we already had a read lock.

- [x] `Lock.acquire_write()` return `False` in cases where we already had
       a read lock.
2019-12-23 18:36:56 -08:00
Todd Gamblin
bb517fdb84 lock transactions: ensure that nested write transactions write
If a write transaction was nested inside a read transaction, it would not
write properly on release, e.g., in a sequence like this, inside our
`LockTransaction` class:

```
1  with spack.store.db.read_transaction():
2    with spack.store.db.write_transaction():
3      ...
4  with spack.store.db.read_transaction():
   ...
```

The WriteTransaction on line 2 had no way of knowing that its
`__exit__()` call was the last *write* in the nesting, and it would skip
calling its write function.

The `__exit__()` call of the `ReadTransaction` on line 1 wouldn't know
how to write, and the file would never be written.

The DB would be correct in memory, but the `ReadTransaction` on line 4
would re-read the whole DB assuming that other processes may have
modified it.  Since the DB was never written, we got stale data.

- [x] Make `Lock.release_write()` return `True` whenever we release the
      *last write* in a nest.
2019-12-23 18:36:56 -08:00
Todd Gamblin
eb8fc4f3be lock transactions: fix non-transactional writes
Lock transactions were actually writing *after* the lock was
released. The code was looking at the result of `release_write()` before
writing, then writing based on whether the lock was released.  This is
pretty obviously wrong.

- [x] Refactor `Lock` so that a release function can be passed to the
      `Lock` and called *only* when a lock is really released.

- [x] Refactor `LockTransaction` classes to use the release function
  instead of checking the return value of `release_read()` / `release_write()`
2019-12-23 18:36:56 -08:00
Massimiliano Culpo
80495d83ed microarchitectures: fix ppc flags for clang (#14196) 2019-12-20 14:40:54 -08:00
Adam J. Stewart
18c2029fef Fix argparse rST parsing of help messages (#14014)
Thanks!
2019-12-17 10:23:22 -08:00
Massimiliano Culpo
5eca4f1470 microarchitectures: readable names for AArch64 vendors (#13825)
Vendors for ARM come out of `/proc/cpuinfo` as hex numbers instead of readable strings.

- Add support for associating vendor names with the hex numbers.
- Also move these mappings from Python code to `microarchitectures.json`
- Move darwin feature name mappings to `microarchitectures.json` as well
2019-12-17 00:47:50 -08:00
Axel Huebl
d705e96a63 Spec Header Dirs: Only first include/ (#13991)
* CUDA HeaderList: Unit Test

* Spec Header Dirs: Only first include/

Avoid matching recurringly nested include paths that usually
refer to internally shipped libraries in packages.
Example in CUDA Toolkit, shipping a libc++ fork internally
with libcu++ since 10.2.89:
`<prefix>/include/cuda/some/more/details/include/` or
`<prefix>/include/cuda/std/detail/libcxx/include`

regex: non-greedy first match of include

Co-Authored-By: Massimiliano Culpo <massimiliano.culpo@gmail.com>

* CUDA: Re-Enable 10.2.89 as Default
2019-12-06 23:47:03 -08:00
Massimiliano Culpo
e9f027210f Fixed x86-64 optimization flags for clang (#13913)
* Fixed x86-64 optimization flags for clang
* Fixed expected results in unit tests

Before the flags used where the one for llc, the underlying compiler from LLVM IR to machine assembly. It turns out that the semantic of `-march`, `-mtune` and `-mcpu` changes from clang front-end to llc.

I found no definitive reference for the flags submitted in this PR, but I checked the assembly on a vectorizable function using Godbolt's web-site.
2019-12-04 09:11:34 -08:00
Massimiliano Culpo
0684a58d16 Fixed detection for cascadelake microarchitecture (#13820)
fixes #13803
2019-11-21 13:09:48 -07:00
t-karatsu
513fe55fc3 Features/expand microarch for aarch64 (#13780)
* Add process to determine aarch64 microarchitecture

* add microarchitectures for thunderx2 and a64fx

* Add optimize flags for gcc on aarch64 family processors thunderx2 and a64fx.

* Add optimize flags for clang on aarch64 family processors thunderx2 and a64fx

* Add testing for thunderx2 and a64fx microarchitectures
2019-11-20 00:01:12 -07:00
Greg Becker
230c6aa326 cpu: fix clang flags for generic x86_64 (#13491)
* cpu: differentiate flags used for pristine LLVM vs. Apple's version
2019-10-30 17:16:13 -05:00
Chris Green
77af4684aa Improvements to detection of AMD architectures. (#13407)
New entry for K10 microarchitecture.

Reorder Zen* microarchitectures to avoid triggering as k10.

Remove some desktop-specific flags that were preventing Opteron Bulldozer/Piledriver/Steamroller/Excavator CPUs from being recognized as such.

Remove one or two flags which weren't produced in /proc/cpuinfo on older OS (RHEL6 and friends).
2019-10-24 15:48:54 -07:00
Chris Green
0913328812 Correctly identify Skylake CPUs on Darwin. (#13377)
* Correctly identify Skylake CPUs on Darwin.

* Add a test for haswell on Mojave.
2019-10-24 12:44:58 -05:00
Massimiliano Culpo
b14f18acda microarchitectures: look in /sbin and /usr/sbin for sysctl (#13365)
This PR ensures that on Darwin we always append /sbin and /usr/sbin to PATH, if they are not already present, when looking for sysctl.

* Make sure we look into /sbin and /usr/sbin for sysctl
* Refactor sysctl for better readability
* Remove marker to make test pass
2019-10-22 21:42:38 -07:00
Massimiliano Culpo
8808207ddf Fixed optimization flags support for old GCC versions (#13362)
These changes update our gcc microarchitecture descriptions based on manuals found here https://gcc.gnu.org/onlinedocs/ and assuming that new architectures are not added during patch releases.
2019-10-22 21:40:45 -07:00
Massimiliano Culpo
cfbdd2179e microarchitectures: add optimization flags for Intel compilers (#13345)
* Added optimization flags for Intel compilers with Intel CPUs
* Added optimization flags for Intel compilers with AMD CPUs
2019-10-22 00:33:59 -07:00
Massimiliano Culpo
498f448ef3 microarchitectures: fix custom compiler versions (#13222)
Custom string versions for compilers were raising a ValueError on
conversion to int. This commit fixes the behavior by trying to detect
the underlying compiler version when in presence of a custom string
version.

* Refactor code that deals with custom versions for better readability
* Partition version components with a regex
* Fix semantic of custom compiler versions with a suffix
* clang@x.y-apple has been special-cased
* Add unit tests
2019-10-21 10:24:57 -07:00
Massimiliano Culpo
41fb0395a6 Microarchitecture specific optimizations for LLVM (#13250)
* Added architecture specific optimization flags for Clang / LLVM
* Disallow compiler optimizations for mixed toolchains
    * We emit a warning when building for a mixed toolchain
* Fixed issues with suffixed versions of compilers; Apple's Clang will, 
    for the time being, fall back on x86-64 for every compilation.
2019-10-19 13:19:29 -07:00
Michael Kuhn
ffe87ed49f filter_file: fix multiple invocations on the same file (#13234)
Since the backup file is only created on the first invocation, it will
contain the original file without any modifications. Further invocations
will then read the backup file, effectively reverting prior invocations.

This can be reproduced easily by trying to install likwid, which will
try to install into /usr/local. Work around this by creating a temporary
file to read from.
2019-10-16 15:15:24 -07:00
Tamara Dahlgren
1ef71376f2 Bugfix: stage directory permissions and cleaning (#12733)
* This updates stage names to use "spack-stage-" as a prefix.
  This avoids removing non-Spack directories in "spack clean" as
  c141e99 did (in this case so long as they don't contain the
  prefix "spack-stage-"), and also addresses a follow-up issue
  where Spack stage directories were not removed.
* Spack now does more-stringent checking of expected permissions for
  staging directories. For a given stage root that includes a user
  component, all directories before the user component that are
  created by Spack are expected to match the permissions of their
  parent; the user component and all deeper directories are expected
  to be accessible to the user (read/write/execute).
2019-10-16 14:55:37 -07:00
Greg Becker
94e80933f0 Feature: installed file verification (#12841)
This feature generates a verification manifest for each installed
package and provides a command, "spack verify", which can be used to
compare the current file checksums/permissions with those calculated
at installed time.

Verification includes

* Checksums of files
* File permissions
* Modification time
* File size

Packages installed before this PR will be skipped during verification.
To verify such a package you must reinstall it.

The spack verify command has three modes.

* With the -a,--all option it will check every installed package.
* With the -f,--files option, it will check some specific files,
  determine which package they belong to, and confirm that they have
  not been changed.
* With the -s,--specs option or by default, it will check some
  specific packages that no files havae changed.
2019-10-15 14:24:52 -07:00
Massimiliano Culpo
5cd28847e8 filter_file uses "surrogateescape" error handling (#12765)
From Python docs:
--
'surrogateescape' will represent any incorrect bytes as code points in
the Unicode Private Use Area ranging from U+DC80 to U+DCFF. These
private code points will then be turned back into the same bytes when
the surrogateescape error handler is used when writing data. This is
useful for processing files in an unknown encoding.
--

This will allow us to process files with unknown encodings.

To accommodate the case of self-extracting bash scripts, filter_file
can now stop filtering text input if a certain marker is found. The
marker must be passed at call time via the "stop_at" function argument.
At that point the file will be reopened in binary mode and copied
verbatim.

* use "surrogateescape" error handling to ignore unknown chars
* permit to stop filtering if a marker is found
* add unit tests for non-ASCII and mixed text/binary files
2019-10-14 20:35:14 -07:00
Massimiliano Culpo
8dd95c1705 Fixed options to compile generic code on ppc64 and ppc64le 2019-10-11 21:20:28 -07:00
Massimiliano Culpo
b07460ab5f Added NEON to the list of features required for the aarch64 family
Both floating-point and NEON are required in all standard ARMv8
implementations. Theoretically though specialized markets can support
no NEON or floating-point at all. Source:

https://developer.arm.com/docs/den0024/latest/aarch64-floating-point-and-neon

On the other hand the base procedure call standard for Aarch64
"assumes the availability of the vector registers for passing
floating-point and SIMD arguments". Further "the Arm 64-bit
architecture defines two mandatory register banks: a general-purpose
register bank which can be used for scalar integer processing and
pointer arithmetic; and a SIMD and Floating-Point register bank".
Source:

https://developer.arm.com/docs/ihi0055/latest/procedure-call-standard-for-the-arm-64-bit-architecture

This makes customization of Aarch64 with no NEON instruction set
available so unlikely that we can consider them a feature of the
generic family.
2019-10-10 16:24:36 -07:00
Massimiliano Culpo
78577c0a90 Generic x86_64 code compiled with GCC uses non deprecated mtune flags (#13022)
fixes #12928
2019-10-03 10:31:03 +02:00
Massimiliano Culpo
9117dfd118 Add all the 'generic' architectures that are mentioned in recipes (#12958)
LLVM, mesa and other packages check for these generic
microarchitectures. One solution is to let Spack know they exist.
2019-09-28 21:47:05 -07:00
Adam J. Stewart
065cbe89fe Fix "specific target" detection in Python 3 (#12906)
The output of subprocess.check_output is a byte string in Python 3. This causes dictionary lookup to fail later on.

A try-except around this function prevented this error from being noticed. Removed this so that more errors can propagate out.
2019-09-24 09:47:54 -07:00
Massimiliano Culpo
2468ccee58 AMD: fix architecture hierarchy (zen) (#12913)
* microarchitectures: zen starts from x86_64, not from excavator
* Unit tests: fixed a test that is wrong with the new modeling
* microarchitectures: fixed features and inheritance for 15h family

bulldozer doesn't inherit from barcelona (10h) + added xop, lwp and tbm
instruction sets to the 15h family (it distinguish the family from 17h)
2019-09-23 21:54:13 -07:00
Gregory Becker
c43f105359 targets: add mic_knl target to microarchitectures.json
- This is needed to support Cray machines -- we need an architecture
  mic_knl > x86_64

- We used Cray's naming scheme for this target to make it work seamlessly
  with the module-based detection sccheme on Cray.  mic_knl is pretty
  much dead, so this will be the last succh target.  We will need to work
  wtih Cray and other vendors in the future.
2019-09-20 00:51:37 -07:00
Massimiliano Culpo
3c4322bf1a targets: Spack targets can now be fine-grained microarchitectures
Spack can now:

- label ppc64, ppc64le, x86_64, etc. builds with specific
  microarchitecture-specific names, like 'haswell', 'skylake' or
  'icelake'.

- detect the host architecture of a machine from /proc/cpuinfo or similar
  tools.

- Understand which microarchitectures are compatible with which (for
  binary reuse)

- Understand which compiler flags are needed (for GCC, so far) to build
  binaries for particular microarchitectures.

All of this is managed through a JSON file (microarchitectures.json) that
contains detailed auto-detection, compiler flag, and compatibility
information for specific microarchitecture targets.  The `llnl.util.cpu`
module implements a library that allows detection and comparison of
microarchitectures based on the data in this file.

The `target` part of Spack specs is now essentially a Microarchitecture
object, and Specs' targets can be compared for compatibility as well.
This allows us to label optimized binary packages at a granularity that
enables them to be reused on compatible machines.  Previously, we only
knew that a package was built for x86_64, NOT which x86_64 machines it
was usable on.

Currently this feature supports Intel, Power, and AMD chips. Support for
ARM is forthcoming.

Specifics:

- Add microarchitectures.json with descriptions of architectures

- Relaxed semantic of compiler's "target" attribute.  Before this change
  the semantic to check if a compiler could be viable for a given target
  was exact match. This made sense as the finest granularity of targets
  was architecture families.  As now we can target micro-architectures,
  this commit changes the semantic by interpreting as the architecture
  family what is stored in the compiler's "target" attribute. A compiler
  is then a viable choice if the target being concretized belongs to the
  same family. Similarly when a new compiler is detected the architecture
  family is stored in the "target" attribute.

- Make Spack's `cc` compiler wrapper inject target-specific flags on the
  command line

- Architecture concretization updated to use the same algorithm as
  compiler concretization

- Micro-architecture features, vendor, generation etc. are included in
  the package hash.  Generic architectures, such as x86_64 or ppc64, are
  still dumped using the name only.

- If the compiler for a target is not supported exit with an intelligible
  error message. If the compiler support is unknown don't try to use
  optimization flags.

- Support and define feature aliases (e.g., sse3 -> ssse3) in
  microarchitectures.json and on Microarchitecture objects. Feature
  aliases are defined in targets.json and map a name (the "alias") to a
  list of rules that must be met for the test to be successful. The rules
  that are available can be extended later using a decorator.

- Implement subset semantics for comparing microarchitectures (treat
  microarchitectures as a partial order, i.e. (a < b), (a == b) and (b <
  a) can all be false.

- Implement logic to automatically demote the default target if the
  compiler being used is too old to optimize for it. Updated docs to make
  this behavior explicit.  This avoids surprising the user if the default
  compiler is older than the host architecture.

This commit adds unit tests to verify the semantics of target ranges and
target lists in constraints. The implementation to allow target ranges
and lists is minimal and doesn't add any new type.  A more careful
refactor that takes into account the type system might be due later.

Co-authored-by: Gregory Becker <becker33.llnl.gov>
2019-09-20 00:51:37 -07:00
Gregory Becker
dfabf5d6b1 targets: first pass at target detection for linux
Add llnl.util.cpu_name, with initial support for detecting different
microarchitectures on Linux.  This also adds preliminary changes for
compiler support and variants to control the optimizatoin levels by
target.

This does not yet include translations of targets to particular
compilers; that is left to another PR.

Co-authored-by: Massimiliano Culpo <massimiliano.culpo@gmail.com>
2019-09-20 00:51:37 -07:00
Peter Scheibel
141a1648e6 implicit rpaths filtering (#12789)
* implicit_rpaths are now removed from compilers.yaml config and are always instantiated dynamically, this occurs one time in the build_environment module

* per-compiler list required libraries (e.g. libstdc++, libgfortran) and whitelist directories from rpaths including those libraries. Remove non-whitelisted implicit rpaths. Some libraries default for all compilers.

* reintroduce 'implicit_rpaths' as a config variable that can be used to disable Spack insertion of compiler RPATHs generated at build time.
2019-09-17 17:45:21 -05:00
Greg Becker
3b115fffb1 permissions: fix file permissions on intermediate install directories (#12399)
- mkdirp now takes arguments to allow it to properly set permissions on created directories.
- Two arguments (group and mode) set permissions for the leaf directory.
- Intermediate directories can inherit permissions from either the topmost existing directory (the parent) or the leaf.
2019-08-20 23:08:02 -07:00
Tamara Dahlgren
0ea6e0f817 features: Remove stage symlinks (#12072)
Fixes #11163

The goal of this work is to simplify stage directory structures by eliminating use of symbolic links. This means, among other things, that` $spack/var/spack/stage` will no longer be the core staging directory. Instead, the first accessible `config:build_stage` path will be used.

Spack will no longer automatically append `spack-stage` (or the like) to configured build stage directories so the onus of distinguishing the directory from other work -- so the other work is not automatically removed with a `spack clean` operation -- falls on the user.
2019-08-19 10:31:24 -07:00
albestro
3a026f1412 Fix #11240 (#11995)
* extends mkdirs with permissions for intermediate folders

Does not use os.makedirs mode parameter because its behavior is changed
with Python 3.7 (it ignores it for intermediate dirs), and moreover it
was not possible to set different modes for newly-created folders
and leaf folder.

reference:
- https://bugs.python.org/issue19930
- https://docs.python.org/3.7/library/os.html#os.makedirs

* comment mkdirp step easing code understanding

* revert mkdir to default for package metapath

since metapath is nested in package folder, there is no need
to specify permissions for intermediate folders because the prefix
already exists.

* comment create_install_directory package modes
2019-07-19 10:13:29 -05:00
Tim Fuller
5bc15b2d9a find_libraries searches lib and lib64 before prefix (#11958)
The default library search for a package checks the lib/ and lib64/
directories for libraries before the root prefix, in order to save
time when searching for libraries provided by externals (which e.g.
may have '/usr/' as their root).

This moves that logic into the "find_libraries" utility method so
packages implementing their own custom library search logic can
benefit from it.

This also updates packages which appear to be replicating this logic
exactly, replacing it with a single call to "find_libraries".
2019-07-12 17:46:47 -07:00
Carson Woods
76f1ee5f32 'spack compiler add' resolves relative path to absolute path (#11792)
Fixes #11782

Spack was not properly resolving relative paths to absolute paths
when a relative path was passed to "spack compiler add [PATH]".
Now, if provided a relative path, the absolute path is written to
compilers.yaml rather than the relative path.
2019-07-12 16:06:26 -07:00
Peter Scheibel
284ae9d1cc Resources: use expanded archive name by default (#11688)
For resources, it is desirable to use the expanded archive name of
the resource as the name of the directory when adding it to the root
staging area.

#11528 established 'spack-src' as the universal directory where
source files are placed, which also affected the behavior of
resources managed with Stages.

This adds a new property ('srcdir') to Stage to remember the name of
the expanded source directory, and uses this as the default name when
placing a resource directory in the root staging area.

This also:

* Ensures that downloaded sources are archived using the expanded
  archive name (otherwise Spack will not be able to determine the
  original directory name when using a cached archive).
* Updates working_dir context manager to guarantee restoration of
  original working directory when an exception occurs
* Adds a "temp_cwd" context manager which creates a temporary
  directory and sets it as the working directory
2019-06-20 11:09:31 -07:00
Adam J. Stewart
4e812090c0 Add additional common C++ and Fortran header file extensions (#11600)
* Add additional common C++ and Fortran header file extensions

* Add .hxx extension

* Add .txx and .tcc extensions

* Add .icc extension
2019-06-11 20:13:55 -04:00
Massimiliano Culpo
6d56d45454 Compiler search uses a pool of workers (#10190)
- spack.compilers.find_compilers now uses a multiprocess.pool.ThreadPool to execute
  system commands for the detection of compiler versions.

- A few memoized functions have been introduced to avoid poking the filesystem multiple
  times for the same results.

- Performance is much improved, and Spack no longer fork-bombs the system when doing a `compiler find`
2019-06-07 09:57:26 -07:00
Tamara Dahlgren
8e3fd3f7c2 tty: make tty.* print exception types
- make tty.msg, tty.info, etc. print the exception type and stringified
  message if the message argument is an exception.

- simplify parts of the code that call tty.debug(str(e))

- add extra tty.debug statements in places where exceptions were
  previously ignored
2019-06-05 22:41:28 -07:00
Todd Gamblin
d6f2ff1426 link_tree: add option to merge link trees with relative targets
- previous version of link trees would only do absolute symlinks

- this version can do relative links using merge(relative=True)
2019-05-26 18:23:44 -07:00
Todd Gamblin
6380f1917a commands: Add --header and --update options to spack commands
The Spack documentation currently hard-codes some functionality in
`conf.py`, which makes the doc build less "pluggable" for things like
localized doc builds.

In particular, we unconditionally generate an index of commands and a
package list as part of the docs, but those should really only be done if
things are not up to date.

This commit does the following:

- Add `--header` option to `spack commands` so that it can do the work of
  prepending text to its output.

- Add `--update FILE` option to `spack commands` that makes it generate a
  new command index *only* if FILE is out of date w.r.t. commands in the
  Spack source.

- Simplify code in `conf.py` to use these options and only update the
  command index when needed.
2019-05-26 18:23:44 -07:00
Peter Scheibel
ea1de6b941 Maintain a view for an environment (#10017)
Environments are nowm by default, created with views.  When activated, if an environment includes a view, this view will be added to `PATH`, `CPATH`, and other shell variables to expose the Spack environment in the user's shell.

Example:

```
spack env create e1 #by default this will maintain a view in the directory Spack maintains for the env
spack env create e1 --with-view=/abs/path/to/anywhere
spack env create e1 --without-view
```

The `spack.yaml` manifest file now looks like this:

```
spack:
  specs:
  - python
  view: true #or false, or a string
```

These commands can be used to control the view configuration for the active environment, without hand-editing the `spack.yaml` file:

```
spack env view enable
spack env view envable /abs/path/to/anywhere
spack env view disable
```

Views are automatically updated when specs are installed to an environment. A view only maintains one copy of any package. An environment may refer to a package multiple times, in particular if it appears as a dependency. This PR establishes a prioritization for which environment specs are added to views: a spec has higher priority if it was concretized first. This does not necessarily exactly match the order in which specs were added, for example, given `X->Z` and `Y->Z'`:

```
spack env activate e1
spack add X
spack install Y # immediately concretizes and installs Y and Z'
spack install # concretizes X and Z
```

In this case `Z'` will be favored over `Z`. 

Specs in the environment must be concrete and installed to be added to the view, so there is another minor ordering effect: by default the view maintained for the environment ignores file conflicts between packages. If packages are not installed in order, and there are file conflicts, then the version chosen depends on the order.

Both ordering issues are avoided if `spack install`/`spack add` and `spack install <spec>` are not mixed.
2019-04-10 16:00:12 -07:00