gh-36982: Make pyproject.toml the source for build dependencies
    
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As noted in
#36951 (comment), the
fact that the dependency declaration of sage-the-library depends on
information contain in sage-the-distro's build folder is problematic for
the separation of concerns. Sage-the-distro should rely on information
of sage-the-library, not the other way around. Here we fix this for the
build requirements by making `src/pyproject.toml` the single source of
thruth. The corresponding `install-requires.txt` are demoted to mere
indicator files (to be removed later). Moreover, this change allows us
to make `pyproject.toml` a static file (no longer generated by
configure), which should help with downstream packaging.

---

Happy new year!

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### ⌛ Dependencies

- #37796
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URL: #36982
Reported by: Tobias Diez
Reviewer(s): Dima Pasechnik, Gonzalo Tornaría, Matthias Köppe, Tobias Diez

Author: Release Manager

.gitignore

@@ -53,7 +53,6 @@
 
 /src/setup.cfg
 /src/requirements.txt
-/src/pyproject.toml
 /src/Pipfile
 /src/Pipfile.lock
 /Pipfile
@@ -186,6 +185,19 @@ __pycache__/
 build/temp.*/
 build/bin/sage-build-env-config
 
+# Generated files in build
+build/pkgs/cypari/version_requirements.txt
+build/pkgs/cysignals/version_requirements.txt
+build/pkgs/cython/version_requirements.txt
+build/pkgs/gmpy2/version_requirements.txt
+build/pkgs/jupyter_core/version_requirements.txt
+build/pkgs/memory_allocator/version_requirements.txt
+build/pkgs/numpy/version_requirements.txt
+build/pkgs/pkgconfig/version_requirements.txt
+build/pkgs/pplpy/version_requirements.txt
+build/pkgs/setuptools/version_requirements.txt
+build/pkgs/wheel/version_requirements.txt
+
 # Generated files in the top-level source trees
 /pkgs/*/build
 /pkgs/*/dist

Makefile

@@ -175,9 +175,19 @@ bootstrap-clean:
 	rm -rf src/doc/en/reference/spkg/*.rst
 	for a in environment environment-optional src/environment src/environment-dev src/environment-optional; do rm -f $$a.yml $$a-3.[89].yml $$a-3.1[0-9].yml; done
 	rm -f src/Pipfile
-	rm -f src/pyproject.toml
 	rm -f src/requirements.txt
 	rm -f src/setup.cfg
+	rm -f build/pkgs/cypari/version_requirements.txt
+	rm -f build/pkgs/cysignals/version_requirements.txt
+	rm -f build/pkgs/cython/version_requirements.txt
+	rm -f build/pkgs/gmpy2/version_requirements.txt
+	rm -f build/pkgs/jupyter_core/version_requirements.txt
+	rm -f build/pkgs/memory_allocator/version_requirements.txt
+	rm -f build/pkgs/numpy/version_requirements.txt
+	rm -f build/pkgs/pkgconfig/version_requirements.txt
+	rm -f build/pkgs/pplpy/version_requirements.txt
+	rm -f build/pkgs/setuptools/version_requirements.txt
+	rm -f build/pkgs/wheel/version_requirements.txt
 
 # Remove absolutely everything which isn't part of the git repo
 maintainer-clean: distclean bootstrap-clean

bootstrap

@@ -35,6 +35,15 @@ CONFVERSION=$(cat $PKG/package-version.txt)
 
 
 bootstrap () {
+    for pkgname in cypari cysignals cython gmpy2 jupyter_core memory_allocator numpy pkgconfig pplpy setuptools wheel; do
+        # Write the version_requirements.txt files for dependencies declared in pyproject.toml
+        target=build/pkgs/${pkgname}/version_requirements.txt
+        if [ "${BOOTSTRAP_QUIET}" = "no" ]; then
+            echo "bootstrap:$LINENO: installing '"$target"'"
+        fi
+        echo "# Generated by SAGE_ROOT/bootstrap based on src/pyproject.toml; do not edit directly" > $target
+        sage-get-system-packages install-requires ${pkgname} >> $target
+    done
     for a in m4/sage_spkg_configures.m4 m4/sage_spkg_versions.m4 m4/sage_spkg_versions_toml.m4; do
         if [ "${BOOTSTRAP_QUIET}" = "no" ]; then
             echo "bootstrap:$LINENO: installing '"$a"'"
@@ -233,7 +242,18 @@ save () {
 	src/Pipfile \
 	src/pyproject.toml \
 	src/requirements.txt \
-	src/setup.cfg
+	src/setup.cfg \
+	build/pkgs/cypari/version_requirements.txt \
+	build/pkgs/cysignals/version_requirements.txt \
+	build/pkgs/cython/version_requirements.txt \
+	build/pkgs/gmpy2/version_requirements.txt \
+	build/pkgs/jupyter_core/version_requirements.txt \
+	build/pkgs/memory_allocator/version_requirements.txt \
+	build/pkgs/numpy/version_requirements.txt \
+	build/pkgs/pkgconfig/version_requirements.txt \
+	build/pkgs/pplpy/version_requirements.txt \
+	build/pkgs/setuptools/version_requirements.txt \
+	build/pkgs/wheel/version_requirements.txt
 
     # Update version
     echo "$NEWCONFVERSION" >$PKG/package-version.txt

build/bin/sage-get-system-packages

@@ -14,22 +14,25 @@ fi
 
 case "$SYSTEM" in
     install-requires)
-        # Collect version_requirements.txt (falling back to requirements.txt) and output it in the format
+        # Collect from src/pyproject.toml or from version_requirements.txt (falling back to requirements.txt) and output it in the format
         # needed by setup.cfg [options] version_requirements=
         SYSTEM_PACKAGES_FILE_NAMES="version_requirements.txt requirements.txt"
         STRIP_COMMENTS="sed s/#.*//;/^[[:space:]]*$/d;"
+        FROM_PYPROJECT_TOML=1
         COLLECT=
         ;;
     install-requires-toml)
-        # Collect version_requirements.txt (falling back to requirements.txt) and output it in the format
+        # Collect from src/pyproject.toml or from version_requirements.txt (falling back to requirements.txt) and output it in the format
         # needed by pyproject.toml [build-system] requires=
         SYSTEM_PACKAGES_FILE_NAMES="version_requirements.txt requirements.txt"
         STRIP_COMMENTS="sed s/#.*//;/^[[:space:]]*$/d;s/^/'/;s/$/',/;"
+        FROM_PYPROJECT_TOML=1
         COLLECT=
         ;;
     pip)
         SYSTEM_PACKAGES_FILE_NAMES="requirements.txt version_requirements.txt"
         STRIP_COMMENTS='sed s/#.*//;s/[[:space:]]//g;'
+        FROM_PYPROJECT_TOML=1
         COLLECT=echo
         ;;
     *)
@@ -42,11 +45,24 @@ case "$SYSTEM" in
         fi
         SYSTEM_PACKAGES_FILE_NAMES="distros/$SYSTEM.txt"
         STRIP_COMMENTS="sed s/#.*//;s/\${PYTHON_MINOR}/${PYTHON_MINOR}/g"
+        FROM_PYPROJECT_TOML=0
         COLLECT=echo
         ;;
 esac
-for PKG_BASE in $SPKGS; do
 
+for PKG_BASE in $SPKGS; do
+    if [ $FROM_PYPROJECT_TOML -eq 1 ]; then
+        if [ -f "$SAGE_ROOT/src/pyproject.toml" ]; then
+            # Extract from the "requires" block in src/pyproject.toml
+            # Packages are in the format "'sage-conf ~= 10.3b3',"
+            PACKAGE_INFO=$(sed -n '/requires *= *\[/,/^\]/s/^ *'\''\('$PKG_BASE'.*\)'\'',/\1/p' "$SAGE_ROOT/src/pyproject.toml")
+            if [ -n "$PACKAGE_INFO" ]; then
+                echo "$PACKAGE_INFO" | ${STRIP_COMMENTS}
+                continue
+            fi
+        fi
+    fi
+    
     case "$SYSTEM:$ENABLE_SYSTEM_SITE_PACKAGES" in
         install-requires*|pip*)
             # This is output for installation of packages into a Python environment.
@@ -73,12 +89,12 @@ for PKG_BASE in $SPKGS; do
     for NAME in $SYSTEM_PACKAGES_FILE_NAMES; do
         SYSTEM_PACKAGES_FILE="$SAGE_ROOT"/build/pkgs/$PKG_BASE/$NAME
         if [ -f $SYSTEM_PACKAGES_FILE ]; then
-           if [ -z "$COLLECT" ]; then
-              ${STRIP_COMMENTS} $SYSTEM_PACKAGES_FILE
-           else
-              $COLLECT $(${STRIP_COMMENTS} $SYSTEM_PACKAGES_FILE)
-           fi
-           break
+            if [ -z "$COLLECT" ]; then
+                ${STRIP_COMMENTS} $SYSTEM_PACKAGES_FILE
+            else
+                $COLLECT $(${STRIP_COMMENTS} $SYSTEM_PACKAGES_FILE)
+            fi
+            break
         fi
     done
 done