Restructure CI to use reusable steps, and add new checks

The goal of this change is to add tests to catch some recent
regressions that the existing CI missed:

* Validate that the proper files get installed. A recent
  innocuous-seeming change to the cmake config caused libdeflate files
  to make it into the installation and we didn't catch it.

  This change introduces a validation step that compares the
  install_mantifest.txt file from each job to a reference maintained
  in share/ci/install_manifest. Each job has a "build" number that
  identifies the reference manifest.

  NOTE: This means that all future changes to installed headers and
  libraries must be reflected in these manifests.

* Validate building against prebuilt/external Imath and libdeflate
  libraries, and also test the "force internal" option.

* Validate building with custom namespaces

To make the workflow files easier to maintain, this splits two parts:

* The ci_steps.yml file declares a common set of steps for Linux,
  macOS, and Windows, and a set of variables named to match the
  various CMake configuration options.

* The ci_workflow.yml invokes these steps with a succession of builds
  that provide collections of CMake settings, which is passes to the
  reusable workflow via the "with:" statement. The "with:" statements
  provide default variable settings, which means each build specifies
  only non-default settings, for a compact summary of what's unique
  about that job.

Some notes:

* By default, the builds now pre-install Imath and libdeflate, so that
  the main OpenEXR build picks them up. A special build now validates
  the behavior of OPENEXR_FORCE_INTERNAL_IMATH and
  OPENEXR_FORCE_INTERNAL_DEFLATE, which were previously untested.

* For each OS, we now build and test these configurations:
  1. Release
  2. Debug
  3. Static
  4. Threading disabled
  5. pkgconfig, docs, examples, tools disabled. This was also previously not
     tested.
  6. Legacy VFX reference platform compiler(s) and/or os(s)

* The "label:" setting forms the description of the job on the GitHub
  Acions page, prepended with the OS and "build" number, which makes
  it easier to cross reference between the entries on the Actions page
  and the workflow file.

* We no longer build with clang on Linux, since we do a clang build on
  macOS.

Signed-off-by: Cary Phillips <cary@ilm.com>

.github/workflows/ci_steps.yml

@@ -0,0 +1,174 @@
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (c) Contributors to the OpenEXR Project.
+
+# These are the steps for all CI jobs. Linux, macOS, and Windows all
+# share a common set of configure/build/validate steps.  The input
+# variables control all variations of the jobs.
+#
+# Each job validates that the proper files are installed by comparing
+# the install_manifest.txt to a reference for that job. This requires
+# that each job have a corresponding reference, and that thes
+# references are updated when any change is made to the installation
+# headers/libraries/cmake/etc.
+
+name: CI Steps
+
+on:
+  workflow_call:
+    # This inputs receive values via the "with:" section in ci_workflow.yml
+    inputs:
+      build:
+        type: string
+      os:
+        type: string
+      container:
+        type: string
+      cxx-standard:
+        type: string
+      build-type:
+        type: string
+      BUILD_SHARED_LIBS:
+        type: string
+      OPENEXR_ENABLE_THREADING:
+        type: string
+      OPENEXR_INSTALL_PKG_CONFIG:
+        type: string
+      OPENEXR_INSTALL_DOCS:
+        type: string
+      OPENEXR_BUILD_EXAMPLES:
+        type: string
+      OPENEXR_BUILD_TOOLS:
+        type: string
+      OPENEXR_FORCE_INTERNAL_IMATH:
+        type: string
+      OPENEXR_FORCE_INTERNAL_DEFLATE:
+        type: string
+      BUILD_TESTING:
+        type: string
+      namespace:
+        type: string
+      validate_install:
+        type: string
+
+jobs:
+  ci_steps:
+    runs-on: ${{ inputs.os }}
+
+    container:
+      image: ${{ inputs.container }}
+
+    env:
+      ACTIONS_RUNNER_FORCE_ACTIONS_NODE_VERSION: node16
+      ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION: true
+
+    steps:
+
+      - name: Checkout
+        uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3.6.0
+
+      - name: Install Imath
+        # Pre-install Imath so the builds validate finding the external installation
+        if: ${{ inputs.OPENEXR_FORCE_INTERNAL_IMATH == 'OFF' }}
+        run: share/ci/scripts/install_imath.sh main
+
+      - name: Install libdeflate
+        # Pre-install libdeflate so the builds validate finding the external installation
+        if: ${{ inputs.OPENEXR_FORCE_INTERNAL_DEFLATE == 'OFF' }}
+        run: share/ci/scripts/install_libdeflate.sh master
+
+      - name: Install help2man
+        # TODO: this could go in the ASWF Linux docker
+        # container. Also, it doesn't currently work for Windows, so
+        # the windows builds have docs disabled.
+        if: ${{ inputs.OPENEXR_INSTALL_DOCS == 'ON' }}
+        run: share/ci/scripts/install_help2man.sh
+
+      - name: Create build directories
+        run: mkdir _install _build _examples
+        shell: bash
+
+      - name: Construct CMake command
+        run: |
+          # Construct the cmake command as a variable, so the
+          # Configure step below can execute it, but also so we can store
+          # in in the install_manifest as a debugging reference
+          CMAKE_COMMAND="cmake -B . -S .. \
+                -DCMAKE_INSTALL_PREFIX=../_install \
+                -DCMAKE_BUILD_TYPE=${{ inputs.build-type }} \
+                -DOPENEXR_CXX_STANDARD=${{ inputs.cxx-standard }} \
+                -DBUILD_SHARED_LIBS=${{ inputs.BUILD_SHARED_LIBS }} \
+                -DOPENEXR_ENABLE_THREADING=${{ inputs.OPENEXR_ENABLE_THREADING }} \
+                -DOPENEXR_INSTALL_PKG_CONFIG=${{ inputs.OPENEXR_INSTALL_PKG_CONFIG }} \
+                -DOPENEXR_INSTALL_DOCS=${{ inputs.OPENEXR_INSTALL_DOCS }} \
+                -DOPENEXR_BUILD_EXAMPLES=${{ inputs.OPENEXR_BUILD_EXAMPLES }} \
+                -DOPENEXR_BUILD_TOOLS=${{ inputs.OPENEXR_BUILD_TOOLS }} \
+                -DOPENEXR_FORCE_INTERNAL_IMATH=${{ inputs.OPENEXR_FORCE_INTERNAL_IMATH }} \
+                -DOPENEXR_FORCE_INTERNAL_DEFLATE=${{ inputs.OPENEXR_FORCE_INTERNAL_DEFLATE }} \
+                -DBUILD_TESTING=${{ inputs.BUILD_TESTING }} \
+                -DOPENEXR_RUN_FUZZ_TESTS=OFF \
+                -DCMAKE_VERBOSE_MAKEFILE=ON"
+          echo "namespace: " ${{ inputs.namespace }}
+          if [ -n "${{ inputs.namespace }}" ]; then
+              CMAKE_COMMAND="$CMAKE_COMMAND \
+                 -DOPENEXR_IMF_NAMESPACE=${{ inputs.namespace }} \
+                 -DILMTHREAD_NAMESPACE=${{ inputs.namespace }} \
+                 -DIEX_NAMESPACE=${{ inputs.namespace }}"
+          fi
+          echo "CMAKE_COMMAND=$CMAKE_COMMAND" >> $GITHUB_ENV
+
+          # Remove the os version from the manifest name, so it only
+          # contains "ubuntu", "macos", or "windows", so the name is,
+          # e.g. install_manifest.macos.1.txt
+          echo "INSTALL_MANIFEST=$(echo 'install_manifest.${{ inputs.os }}' | cut -d'-' -f1).${{ inputs.build }}.txt" >> $GITHUB_ENV
+        working-directory: _build
+        shell: bash
+
+      - name: Configure
+        run: |
+          $CMAKE_COMMAND
+        working-directory: _build
+        shell: bash
+
+      - name: Build
+        run: |
+          cmake --build . --target install --config ${{ inputs.build-type }}
+        working-directory: _build
+        shell: bash
+
+      - name: Prepare install_manifest
+        if: ${{ inputs.validate_install != 'OFF' }}
+        # Store the cmake command as the first line of the manifest,
+        # and remove the path prefix, so the manifest contains only
+        # the local filenames.
+        run: |
+          echo "# $CMAKE_COMMAND" > "_build/$INSTALL_MANIFEST"
+          sort _build/install_manifest.txt | sed -e "s:^.*/_install/::" >> "_build/$INSTALL_MANIFEST"
+        shell: bash
+
+      - name: Upload install_manifest.txt
+        if: ${{ inputs.validate_install != 'OFF' }}
+        # Upload the manifest to make it possible to download for inspection and debugging
+        uses: actions/upload-artifact@v3
+        with:
+          name: install_manifest
+          path: _build/${{ env.INSTALL_MANIFEST }}
+
+      - name: Validate install
+        if: ${{ inputs.validate_install != 'OFF' }}
+        # Validate that the build has installed the proper files by comparing against the appropriate reference manifest
+        run: |
+          share/ci/scripts/validate_install.py "_build/$INSTALL_MANIFEST" "share/ci/install_manifest/$INSTALL_MANIFEST"
+        shell: bash
+
+      - name: Set PATH for Imath/libdeflate DLLs
+        # When building against external Imath/libdeflate shared objects, the tests need PATH to include the dll's.
+        if: contains(inputs.os, 'windows')
+        run: |
+          echo "$PATH;C:/Program Files (x86)/Imath/bin;C:/Program Files (x86)/Imath/lib;C:/Program Files (x86)/libdeflate/bin;C:/Program Files (x86)/libdeflate/lib" >> $GITHUB_PATH
+        shell: bash
+
+      - name: Test
+        run: |
+          ctest -T Test -C ${{ inputs.build-type }} --timeout 7200 --output-on-failure -VV
+        working-directory: _build
+        shell: bash