bigdft: convert the use of format strings to fstrings. (#42006)

* bigdft: convert the use of format strings to fstrings everywhere

* Fix formatting

* reformat with black

* Update compiler flags in bigdft-core

* Revert "Update compiler flags in bigdft-core"

This reverts commit f7524ed78449b16163c92bf0ccc8b0dd473039dc.

7 files changed, 135 insertions, 132 deletions

diff --git a/var/spack/repos/builtin/packages/bigdft-atlab/package.py b/var/spack/repos/builtin/packages/bigdft-atlab/package.py
index af1500f4c0..c74113c0dc 100644
--- a/var/spack/repos/builtin/packages/bigdft-atlab/package.py
+++ b/var/spack/repos/builtin/packages/bigdft-atlab/package.py
@@ -33,7 +33,7 @@ class BigdftAtlab(AutotoolsPackage):
     depends_on("openbabel", when="+openbabel")
 
     for vers in ["1.9.0", "1.9.1", "1.9.2", "develop"]:
-        depends_on("bigdft-futile@{0}".format(vers), when="@{0}".format(vers))
+        depends_on(f"bigdft-futile@{vers}", when=f"@{vers}")
 
     configure_directory = "atlab"
 
@@ -56,24 +56,24 @@ class BigdftAtlab(AutotoolsPackage):
             fcflags.append("-fallow-argument-mismatch")
 
         args = [
-            "FCFLAGS=%s" % " ".join(fcflags),
-            "CFLAGS=%s" % " ".join(cflags),
-            "CXXFLAGS=%s" % " ".join(cxxflags),
-            "--with-futile-libs=%s" % spec["bigdft-futile"].libs.ld_flags,
-            "--with-futile-incs=%s" % spec["bigdft-futile"].headers.include_flags + "/futile",
-            "--with-moduledir=%s" % prefix.include,
-            "--prefix=%s" % prefix,
+            f"FCFLAGS={' '.join(fcflags)}",
+            f"CFLAGS={' '.join(cflags)}",
+            f"CXXFLAGS={' '.join(cxxflags)}",
+            f"--with-futile-libs={spec['bigdft-futile'].libs.ld_flags}",
+            f"--with-futile-incs={spec['bigdft-futile'].headers.include_flags}/futile",
+            f"--with-moduledir={prefix.include}",
+            f"--prefix={prefix}",
             "--without-etsf-io",
         ]
         if spec.satisfies("+shared"):
             args.append("--enable-dynamic-libraries")
 
         if "+mpi" in spec:
-            args.append("CC=%s" % spec["mpi"].mpicc)
-            args.append("CXX=%s" % spec["mpi"].mpicxx)
-            args.append("FC=%s" % spec["mpi"].mpifc)
-            args.append("F90=%s" % spec["mpi"].mpifc)
-            args.append("F77=%s" % spec["mpi"].mpif77)
+            args.append(f"CC={spec['mpi'].mpicc}")
+            args.append(f"CXX={spec['mpi'].mpicxx}")
+            args.append(f"FC={spec['mpi'].mpifc}")
+            args.append(f"F90={spec['mpi'].mpifc}")
+            args.append(f"F77={spec['mpi'].mpif77}")
         else:
             args.append("--disable-mpi")
 
@@ -84,8 +84,8 @@ class BigdftAtlab(AutotoolsPackage):
 
         if "+openbabel" in spec:
             args.append("--enable-openbabel")
-            args.append("--with-openbabel-libs=%s" % spec["openbabel"].prefix.lib)
-            args.append("--with-openbabel-incs=%s" % spec["openbabel"].prefix.include)
+            args.append(f"--with-openbabel-libs={spec['openbabel'].prefix.lib}")
+            args.append(f"--with-openbabel-incs={spec['openbabel'].prefix.include}")
 
         return args
 
diff --git a/var/spack/repos/builtin/packages/bigdft-chess/package.py b/var/spack/repos/builtin/packages/bigdft-chess/package.py
index 5ff540f7c8..dc5ba9362a 100644
--- a/var/spack/repos/builtin/packages/bigdft-chess/package.py
+++ b/var/spack/repos/builtin/packages/bigdft-chess/package.py
@@ -43,8 +43,8 @@ class BigdftChess(AutotoolsPackage, CudaPackage):
     # depends_on('netlib-minpack', when='+minpack')
 
     for vers in ["1.9.0", "1.9.1", "1.9.2", "develop"]:
-        depends_on("bigdft-futile@{0}".format(vers), when="@{0}".format(vers))
-        depends_on("bigdft-atlab@{0}".format(vers), when="@{0}".format(vers))
+        depends_on(f"bigdft-futile@{vers}", when=f"@{vers}")
+        depends_on(f"bigdft-atlab@{vers}", when=f"@{vers}")
 
     configure_directory = "chess"
 
@@ -53,7 +53,7 @@ class BigdftChess(AutotoolsPackage, CudaPackage):
         prefix = self.prefix
 
         python_version = spec["python"].version.up_to(2)
-        pyyaml = join_path(spec["py-pyyaml"].prefix.lib, "python{0}".format(python_version))
+        pyyaml = join_path(spec["py-pyyaml"].prefix.lib, f"python{python_version}")
 
         openmp_flag = []
         if "+openmp" in spec:
@@ -66,25 +66,25 @@ class BigdftChess(AutotoolsPackage, CudaPackage):
         linalg.append(spec["blas"].libs.ld_flags)
 
         args = [
-            "FCFLAGS=%s" % " ".join(openmp_flag),
-            "LDFLAGS=%s" % " ".join(linalg),
-            "--with-ext-linalg=%s" % " ".join(linalg),
-            "--with-pyyaml-path=%s" % pyyaml,
-            "--with-futile-libs=%s" % spec["bigdft-futile"].libs.ld_flags,
-            "--with-futile-incs=%s" % spec["bigdft-futile"].headers.include_flags,
-            "--with-moduledir=%s" % prefix.include,
-            "--prefix=%s" % prefix,
+            f"FCFLAGS={' '.join(openmp_flag)}",
+            f"LDFLAGS={' '.join(linalg)}",
+            f"--with-ext-linalg={' '.join(linalg)}",
+            f"--with-pyyaml-path={pyyaml}",
+            f"--with-futile-libs={spec['bigdft-futile'].libs.ld_flags}",
+            f"--with-futile-incs={spec['bigdft-futile'].headers.include_flags}",
+            f"--with-moduledir={prefix.include}",
+            f"--prefix={prefix}",
             "--without-etsf-io",
         ]
         if spec.satisfies("+shared"):
             args.append("--enable-dynamic-libraries")
 
         if "+mpi" in spec:
-            args.append("CC=%s" % spec["mpi"].mpicc)
-            args.append("CXX=%s" % spec["mpi"].mpicxx)
-            args.append("FC=%s" % spec["mpi"].mpifc)
-            args.append("F90=%s" % spec["mpi"].mpifc)
-            args.append("F77=%s" % spec["mpi"].mpif77)
+            args.append(f"CC={spec['mpi'].mpicc}")
+            args.append(f"CXX={spec['mpi'].mpicxx}")
+            args.append(f"FC={spec['mpi'].mpifc}")
+            args.append(f"F90={spec['mpi'].mpifc}")
+            args.append(f"F77={spec['mpi'].mpif77}")
         else:
             args.append("--disable-mpi")
 
@@ -93,12 +93,12 @@ class BigdftChess(AutotoolsPackage, CudaPackage):
         else:
             args.append("--without-openmp")
 
-        args.append("--with-atlab-libs=%s" % spec["bigdft-atlab"].prefix.lib)
+        args.append(f"--with-atlab-libs={spec['bigdft-atlab'].prefix.lib}")
 
         if "+cuda" in spec:
             args.append("--enable-cuda-gpu")
-            args.append("--with-cuda-path=%s" % spec["cuda"].prefix)
-            args.append("--with-cuda-libs=%s" % spec["cuda"].libs.link_flags)
+            args.append(f"--with-cuda-path={spec['cuda'].prefix}")
+            args.append(f"--with-cuda-libs={spec['cuda'].libs.link_flags}")
 
         if "+minpack" in spec:
             args.append("--with-minpack")
diff --git a/var/spack/repos/builtin/packages/bigdft-core/package.py b/var/spack/repos/builtin/packages/bigdft-core/package.py
index 90146355ee..834b65f377 100644
--- a/var/spack/repos/builtin/packages/bigdft-core/package.py
+++ b/var/spack/repos/builtin/packages/bigdft-core/package.py
@@ -45,10 +45,10 @@ class BigdftCore(AutotoolsPackage, CudaPackage):
     depends_on("libxc@:4.3.4", when="@develop")
 
     for vers in ["1.9.0", "1.9.1", "1.9.2", "develop"]:
-        depends_on("bigdft-futile@{0}".format(vers), when="@{0}".format(vers))
-        depends_on("bigdft-chess@{0}".format(vers), when="@{0}".format(vers))
-        depends_on("bigdft-psolver@{0}".format(vers), when="@{0}".format(vers))
-        depends_on("bigdft-libabinit@{0}".format(vers), when="@{0}".format(vers))
+        depends_on(f"bigdft-futile@{vers}", when=f"@{vers}")
+        depends_on(f"bigdft-chess@{vers}", when=f"@{vers}")
+        depends_on(f"bigdft-psolver@{vers}", when=f"@{vers}")
+        depends_on(f"bigdft-libabinit@{vers}", when=f"@{vers}")
 
     configure_directory = "bigdft"
 
@@ -57,7 +57,7 @@ class BigdftCore(AutotoolsPackage, CudaPackage):
         prefix = self.prefix
 
         python_version = spec["python"].version.up_to(2)
-        pyyaml = join_path(spec["py-pyyaml"].prefix.lib, "python{0}".format(python_version))
+        pyyaml = join_path(spec["py-pyyaml"].prefix.lib, f"python{python_version}")
 
         openmp_flag = []
         if "+openmp" in spec:
@@ -70,35 +70,34 @@ class BigdftCore(AutotoolsPackage, CudaPackage):
         linalg.append(spec["blas"].libs.ld_flags)
 
         args = [
-            "FCFLAGS=%s" % " ".join(openmp_flag),
-            "--with-ext-linalg=%s" % " ".join(linalg),
-            "--with-pyyaml-path=%s" % pyyaml,
-            "--with-futile-libs=%s" % spec["bigdft-futile"].libs.ld_flags,
-            "--with-futile-incs=%s" % spec["bigdft-futile"].headers.include_flags,
-            "--with-chess-libs=%s" % spec["bigdft-chess"].libs.ld_flags,
-            "--with-chess-incs=%s" % spec["bigdft-chess"].headers.include_flags,
-            "--with-psolver-libs=%s" % spec["bigdft-psolver"].libs.ld_flags,
-            "--with-psolver-incs=%s" % spec["bigdft-psolver"].headers.include_flags,
-            "--with-libABINIT-libs=%s" % spec["bigdft-libabinit"].libs.ld_flags,
-            "--with-libABINIT-incs=%s" % spec["bigdft-libabinit"].headers.include_flags,
-            "--with-libgain-libs=%s" % spec["libgain"].libs.ld_flags,
-            "--with-libgain-incs=%s" % spec["libgain"].headers.include_flags,
-            "--with-libxc-libs=%s %s"
-            % (spec["libxc"].libs.ld_flags, spec["libxc"].libs.ld_flags + "f90"),
-            "--with-libxc-incs=%s" % spec["libxc"].headers.include_flags,
-            "--with-moduledir=%s" % prefix.include,
-            "--prefix=%s" % prefix,
+            f"FCFLAGS={' '.join(openmp_flag)}",
+            f"--with-ext-linalg={' '.join(linalg)}",
+            f"--with-pyyaml-path={pyyaml}",
+            f"--with-futile-libs={spec['bigdft-futile'].libs.ld_flags}",
+            f"--with-futile-incs={spec['bigdft-futile'].headers.include_flags}",
+            f"--with-chess-libs={spec['bigdft-chess'].libs.ld_flags}",
+            f"--with-chess-incs={spec['bigdft-chess'].headers.include_flags}",
+            f"--with-psolver-libs={spec['bigdft-psolver'].libs.ld_flags}",
+            f"--with-psolver-incs={spec['bigdft-psolver'].headers.include_flags}",
+            f"--with-libABINIT-libs={spec['bigdft-libabinit'].libs.ld_flags}",
+            f"--with-libABINIT-incs={spec['bigdft-libabinit'].headers.include_flags}",
+            f"--with-libgain-libs={spec['libgain'].libs.ld_flags}",
+            f"--with-libgain-incs={spec['libgain'].headers.include_flags}",
+            f"--with-libxc-libs={spec['libxc'].libs.ld_flags} {spec['libxc'].libs.ld_flags}f90",
+            f"--with-libxc-incs={spec['libxc'].headers.include_flags}",
+            f"--with-moduledir={prefix.include}",
+            f"--prefix={prefix}",
             "--without-etsf-io",
         ]
         if spec.satisfies("+shared"):
             args.append("--enable-dynamic-libraries")
 
         if "+mpi" in spec:
-            args.append("CC=%s" % spec["mpi"].mpicc)
-            args.append("CXX=%s" % spec["mpi"].mpicxx)
-            args.append("FC=%s" % spec["mpi"].mpifc)
-            args.append("F90=%s" % spec["mpi"].mpifc)
-            args.append("F77=%s" % spec["mpi"].mpif77)
+            args.append(f"CC={spec['mpi'].mpicc}")
+            args.append(f"CXX={spec['mpi'].mpicxx}")
+            args.append(f"FC={spec['mpi'].mpifc}")
+            args.append(f"F90={spec['mpi'].mpifc}")
+            args.append(f"F77={spec['mpi'].mpif77}")
         else:
             args.append("--disable-mpi")
 
@@ -109,15 +108,15 @@ class BigdftCore(AutotoolsPackage, CudaPackage):
 
         if "+cuda" in spec:
             args.append("--enable-opencl")
-            args.append("--with-ocl-path=%s" % spec["cuda"].prefix)
+            args.append(f"--with-ocl-path={spec['cuda'].prefix}")
             args.append("--enable-cuda-gpu")
-            args.append("--with-cuda-path=%s" % spec["cuda"].prefix)
-            args.append("--with-cuda-libs=%s" % spec["cuda"].libs.link_flags)
+            args.append(f"--with-cuda-path={spec['cuda'].prefix}")
+            args.append(f"--with-cuda-libs={spec['cuda'].libs.link_flags}")
 
         if "+openbabel" in spec:
             args.append("--enable-openbabel")
-            args.append("--with-openbabel-libs=%s" % spec["openbabel"].prefix.lib)
-            args.append("--with-openbabel-incs=%s" % spec["openbabel"].prefix.include)
+            args.append(f"--with-openbabel-libs={spec['openbabel'].prefix.lib}")
+            args.append(f"--with-openbabel-incs={spec['openbabel'].prefix.include}")
 
         return args
 
diff --git a/var/spack/repos/builtin/packages/bigdft-futile/package.py b/var/spack/repos/builtin/packages/bigdft-futile/package.py
index 3894c503de..13c2e69495 100644
--- a/var/spack/repos/builtin/packages/bigdft-futile/package.py
+++ b/var/spack/repos/builtin/packages/bigdft-futile/package.py
@@ -49,18 +49,18 @@ class BigdftFutile(AutotoolsPackage, CudaPackage):
         linalg = [spec["blas"].libs.ld_flags, spec["lapack"].libs.ld_flags]
 
         python_version = spec["python"].version.up_to(2)
-        pyyaml = join_path(spec["py-pyyaml"].prefix.lib, "python{0}".format(python_version))
+        pyyaml = join_path(spec["py-pyyaml"].prefix.lib, f"python{python_version}")
 
         openmp_flag = []
         if "+openmp" in spec:
             openmp_flag.append(self.compiler.openmp_flag)
 
         args = [
-            "FCFLAGS=%s" % " ".join(openmp_flag),
-            "--with-ext-linalg=%s" % " ".join(linalg),
-            "--with-yaml-path=%s" % spec["libyaml"].prefix,
-            "--with-pyyaml-path=%s" % pyyaml,
-            "--prefix=%s" % prefix,
+            f"FCFLAGS={' '.join(openmp_flag)}",
+            f"--with-ext-linalg={' '.join(linalg)}",
+            f"--with-yaml-path={spec['libyaml'].prefix}",
+            f"--with-pyyaml-path={pyyaml}",
+            f"--prefix={prefix}",
         ]
         if spec.satisfies("+shared"):
             args.append("--enable-dynamic-libraries")
@@ -71,19 +71,19 @@ class BigdftFutile(AutotoolsPackage, CudaPackage):
             args.append("--without-openmp")
 
         if "+mpi" in spec:
-            args.append("CC=%s" % spec["mpi"].mpicc)
-            args.append("CXX=%s" % spec["mpi"].mpicxx)
-            args.append("FC=%s" % spec["mpi"].mpifc)
-            args.append("F90=%s" % spec["mpi"].mpifc)
-            args.append("F77=%s" % spec["mpi"].mpif77)
+            args.append(f"CC={spec['mpi'].mpicc}")
+            args.append(f"CXX={spec['mpi'].mpicxx}")
+            args.append(f"FC={spec['mpi'].mpifc}")
+            args.append(f"F90={spec['mpi'].mpifc}")
+            args.append(f"F77={spec['mpi'].mpif77}")
         else:
             args.append("--disable-mpi")
 
         if "+cuda" in spec:
             args.append("--enable-opencl")
-            args.append("--with-ocl-path=%s" % spec["cuda"].prefix)
+            args.append(f"--with-ocl-path={spec['cuda'].prefix}")
             args.append("--enable-cuda-gpu")
-            args.append("--with-cuda-path=%s" % spec["cuda"].prefix)
+            args.append(f"--with-cuda-path={spec['cuda'].prefix}")
 
         return args
 
diff --git a/var/spack/repos/builtin/packages/bigdft-libabinit/package.py b/var/spack/repos/builtin/packages/bigdft-libabinit/package.py
index 8a514181ae..c88763946b 100644
--- a/var/spack/repos/builtin/packages/bigdft-libabinit/package.py
+++ b/var/spack/repos/builtin/packages/bigdft-libabinit/package.py
@@ -37,7 +37,7 @@ class BigdftLibabinit(AutotoolsPackage):
     depends_on("libxc@:4.3.4", when="@1.9.1:")
 
     for vers in ["1.9.0", "1.9.1", "1.9.2", "develop"]:
-        depends_on("bigdft-futile@{0}".format(vers), when="@{0}".format(vers))
+        depends_on(f"bigdft-futile@{vers}", when=f"@{vers}")
 
     configure_directory = "libABINIT"
 
@@ -50,24 +50,28 @@ class BigdftLibabinit(AutotoolsPackage):
             fcflags.append("-fallow-argument-mismatch")
 
         args = [
-            "FCFLAGS=%s" % " ".join(fcflags),
-            "--with-libxc-libs=%s %s"
-            % (spec["libxc"].libs.ld_flags, spec["libxc"].libs.ld_flags + "f90"),
-            "--with-libxc-incs=%s" % spec["libxc"].headers.include_flags,
-            "--with-futile-libs=%s" % spec["bigdft-futile"].libs.ld_flags,
-            "--with-futile-incs=%s" % spec["bigdft-futile"].headers.include_flags,
-            "--with-moduledir=%s" % prefix.include,
-            "--prefix=%s" % prefix,
+            f"FCFLAGS={' '.join(fcflags)}",
+            f"--with-libxc-libs={spec['libxc'].libs.ld_flags} "
+            f"{spec['libxc'].libs.ld_flags + 'f90'}",
+            f"--with-libxc-incs={spec['libxc'].headers.include_flags}",
+            f"--with-futile-libs={spec['bigdft-futile'].libs.ld_flags}",
+            f"--with-futile-incs={spec['bigdft-futile'].headers.include_flags}",
+            f"--with-moduledir={prefix.include}",
+            f"--prefix={prefix}",
         ]
         if spec.satisfies("+shared"):
             args.append("--enable-dynamic-libraries")
 
         if "+mpi" in spec:
-            args.append("CC=%s" % spec["mpi"].mpicc)
-            args.append("CXX=%s" % spec["mpi"].mpicxx)
-            args.append("FC=%s" % spec["mpi"].mpifc)
-            args.append("F90=%s" % spec["mpi"].mpifc)
-            args.append("F77=%s" % spec["mpi"].mpif77)
+            args.extend(
+                [
+                    f"CC={spec['mpi'].mpicc}",
+                    f"CXX={spec['mpi'].mpicxx}",
+                    f"FC={spec['mpi'].mpifc}",
+                    f"F90={spec['mpi'].mpifc}",
+                    f"F77={spec['mpi'].mpif77}",
+                ]
+            )
         else:
             args.append("--disable-mpi")
 
diff --git a/var/spack/repos/builtin/packages/bigdft-psolver/package.py b/var/spack/repos/builtin/packages/bigdft-psolver/package.py
index b97a5fee0d..2ee1ab488f 100644
--- a/var/spack/repos/builtin/packages/bigdft-psolver/package.py
+++ b/var/spack/repos/builtin/packages/bigdft-psolver/package.py
@@ -40,8 +40,8 @@ class BigdftPsolver(AutotoolsPackage, CudaPackage):
     depends_on("scalapack", when="+scalapack")
 
     for vers in ["1.9.0", "1.9.1", "1.9.2", "develop"]:
-        depends_on("bigdft-futile@{0}".format(vers), when="@{0}".format(vers))
-        depends_on("bigdft-atlab@{0}".format(vers), when="@{0}".format(vers))
+        depends_on(f"bigdft-futile@{vers}", when=f"@{vers}")
+        depends_on(f"bigdft-atlab@{vers}", when=f"@{vers}")
 
     configure_directory = "psolver"
 
@@ -50,7 +50,7 @@ class BigdftPsolver(AutotoolsPackage, CudaPackage):
         prefix = self.prefix
 
         python_version = spec["python"].version.up_to(2)
-        pyyaml = join_path(spec["py-pyyaml"].prefix.lib, "python{0}".format(python_version))
+        pyyaml = join_path(spec["py-pyyaml"].prefix.lib, f"python{python_version}")
 
         openmp_flag = []
         if "+openmp" in spec:
@@ -63,24 +63,24 @@ class BigdftPsolver(AutotoolsPackage, CudaPackage):
         linalg.append(spec["blas"].libs.ld_flags)
 
         args = [
-            "FCFLAGS=%s" % " ".join(openmp_flag),
-            "--with-ext-linalg=%s" % " ".join(linalg),
-            "--with-pyyaml-path=%s" % pyyaml,
-            "--with-futile-libs=%s" % spec["bigdft-futile"].libs.ld_flags,
-            "--with-futile-incs=%s" % spec["bigdft-futile"].headers.include_flags,
-            "--with-moduledir=%s" % prefix.include,
-            "--prefix=%s" % prefix,
+            f"FCFLAGS={' '.join(openmp_flag)}",
+            f"--with-ext-linalg={' '.join(linalg)}",
+            f"--with-pyyaml-path={pyyaml}",
+            f"--with-futile-libs={spec['bigdft-futile'].libs.ld_flags}",
+            f"--with-futile-incs={spec['bigdft-futile'].headers.include_flags}",
+            f"--with-moduledir={prefix.include}",
+            f"--prefix={prefix}",
             "--without-etsf-io",
         ]
         if spec.satisfies("+shared"):
             args.append("--enable-dynamic-libraries")
 
         if "+mpi" in spec:
-            args.append("CC=%s" % spec["mpi"].mpicc)
-            args.append("CXX=%s" % spec["mpi"].mpicxx)
-            args.append("FC=%s" % spec["mpi"].mpifc)
-            args.append("F90=%s" % spec["mpi"].mpifc)
-            args.append("F77=%s" % spec["mpi"].mpif77)
+            args.append(f"CC={spec['mpi'].mpicc}")
+            args.append(f"CXX={spec['mpi'].mpicxx}")
+            args.append(f"FC={spec['mpi'].mpifc}")
+            args.append(f"F90={spec['mpi'].mpifc}")
+            args.append(f"F77={spec['mpi'].mpif77}")
         else:
             args.append("--disable-mpi")
 
@@ -89,12 +89,12 @@ class BigdftPsolver(AutotoolsPackage, CudaPackage):
         else:
             args.append("--without-openmp")
 
-        args.append("--with-atlab-libs=%s" % spec["bigdft-atlab"].prefix.lib)
+        args.append(f"--with-atlab-libs={spec['bigdft-atlab'].prefix.lib}")
 
         if "+cuda" in spec:
             args.append("--enable-cuda-gpu")
-            args.append("--with-cuda-path=%s" % spec["cuda"].prefix)
-            args.append("--with-cuda-libs=%s" % spec["cuda"].libs.link_flags)
+            args.append(f"--with-cuda-path={spec['cuda'].prefix}")
+            args.append(f"--with-cuda-libs={spec['cuda'].libs.link_flags}")
 
         return args
 
diff --git a/var/spack/repos/builtin/packages/bigdft-spred/package.py b/var/spack/repos/builtin/packages/bigdft-spred/package.py
index c0e02da236..14215c3f7f 100644
--- a/var/spack/repos/builtin/packages/bigdft-spred/package.py
+++ b/var/spack/repos/builtin/packages/bigdft-spred/package.py
@@ -39,9 +39,9 @@ class BigdftSpred(AutotoolsPackage):
     depends_on("scalapack", when="+scalapack")
 
     for vers in ["1.9.0", "1.9.1", "1.9.2", "develop"]:
-        depends_on("bigdft-futile@{0}".format(vers), when="@{0}".format(vers))
-        depends_on("bigdft-psolver@{0}".format(vers), when="@{0}".format(vers))
-        depends_on("bigdft-core@{0}".format(vers), when="@{0}".format(vers))
+        depends_on(f"bigdft-futile@{vers}", when=f"@{vers}")
+        depends_on(f"bigdft-psolver@{vers}", when=f"@{vers}")
+        depends_on(f"bigdft-core@{vers}", when=f"@{vers}")
 
     configure_directory = "spred"
 
@@ -50,7 +50,7 @@ class BigdftSpred(AutotoolsPackage):
         prefix = self.prefix
 
         python_version = spec["python"].version.up_to(2)
-        pyyaml = join_path(spec["py-pyyaml"].prefix.lib, "python{0}".format(python_version))
+        pyyaml = join_path(spec["py-pyyaml"].prefix.lib, f"python{python_version}")
 
         openmp_flag = []
         if "+openmp" in spec:
@@ -63,27 +63,27 @@ class BigdftSpred(AutotoolsPackage):
         linalg.append(spec["blas"].libs.ld_flags)
 
         args = [
-            "FCFLAGS=%s" % " ".join(openmp_flag),
-            "--with-ext-linalg=%s" % " ".join(linalg),
-            "--with-pyyaml-path=%s" % pyyaml,
-            "--with-futile-libs=%s" % spec["bigdft-futile"].libs.ld_flags,
-            "--with-futile-incs=%s" % spec["bigdft-futile"].headers.include_flags,
-            "--with-psolver-libs=%s" % spec["bigdft-psolver"].prefix.lib,
-            "--with-psolver-incs=%s" % spec["bigdft-psolver"].headers.include_flags,
-            "--with-core-libs=%s" % spec["bigdft-core"].prefix.lib,
-            "--with-core-incs=%s" % spec["bigdft-core"].headers.include_flags,
-            "--with-moduledir=%s" % prefix.include,
-            "--prefix=%s" % prefix,
+            f"FCFLAGS={' '.join(openmp_flag)}",
+            f"--with-ext-linalg={' '.join(linalg)}",
+            f"--with-pyyaml-path={pyyaml}",
+            f"--with-futile-libs={spec['bigdft-futile'].libs.ld_flags}",
+            f"--with-futile-incs={spec['bigdft-futile'].headers.include_flags}",
+            f"--with-psolver-libs={spec['bigdft-psolver'].prefix.lib}",
+            f"--with-psolver-incs={spec['bigdft-psolver'].headers.include_flags}",
+            f"--with-core-libs={spec['bigdft-core'].prefix.lib}",
+            f"--with-core-incs={spec['bigdft-core'].headers.include_flags}",
+            f"--with-moduledir={prefix.include}",
+            f"--prefix={prefix}",
         ]
         if spec.satisfies("+shared"):
             args.append("--enable-dynamic-libraries")
 
         if "+mpi" in spec:
-            args.append("CC=%s" % spec["mpi"].mpicc)
-            args.append("CXX=%s" % spec["mpi"].mpicxx)
-            args.append("FC=%s" % spec["mpi"].mpifc)
-            args.append("F90=%s" % spec["mpi"].mpifc)
-            args.append("F77=%s" % spec["mpi"].mpif77)
+            args.append(f"CC={spec['mpi'].mpicc}")
+            args.append(f"CXX={spec['mpi'].mpicxx}")
+            args.append(f"FC={spec['mpi'].mpifc}")
+            args.append(f"F90={spec['mpi'].mpifc}")
+            args.append(f"F77={spec['mpi'].mpif77}")
         else:
             args.append("--disable-mpi")