Remove custom python commands from EXE installers (#1089)

* Remove python from base environment where possible

* Fix NSIS template

* Add news file

* Only exit with error if base needs python

* Remove Python logic from NSIS if Python is not in the base environment

* Explain why return code 2 is used in _base_needs_python

* Always set register_python_default

* Consolidate different path removal options

* Remove duplicate code

* Unify uninstallation workflow

* Always show /AddToPath example in help text

* Add post-solve check for mamba

* Do not check for mamba 1 because mamba 1 depends on Python

* Add clarifying comments

* Remove unused installer_type parameter

* Restore base environment python check

* Fix syntax error

Author: marcoesters

constructor/fcp.py

@@ -234,11 +234,9 @@ def _solve_precs(
     conda_exe="conda.exe",
     extra_env=False,
     input_dir="",
+    base_needs_python=True,
 ):
-    # Add python to specs, since all installers need a python interpreter. In the future we'll
-    # probably want to add conda too.
-    # JRG: This only applies to the `base` environment; `extra_envs` are exempt
-    if not extra_env:
+    if not extra_env and base_needs_python:
         specs = (*specs, "python")
     if environment:
         logger.debug("specs: <from existing environment '%s'>", environment)
@@ -312,8 +310,8 @@ def _solve_precs(
     if python_prec:
         precs.remove(python_prec)
         precs.insert(0, python_prec)
-    elif not extra_env:
-        # the base environment must always have python; this has been addressed
+    elif not extra_env and base_needs_python:
+        # the base environment may require python; this has been addressed
         # at the beginning of _main() but we can still get here through the
         # environment_file option
         sys.exit("python MUST be part of the base environment")
@@ -392,6 +390,7 @@ def _main(
     extra_envs=None,
     check_path_spaces=True,
     input_dir="",
+    base_needs_python=True,
 ):
     precs = _solve_precs(
         name,
@@ -408,6 +407,7 @@ def _main(
         verbose=verbose,
         conda_exe=conda_exe,
         input_dir=input_dir,
+        base_needs_python=base_needs_python,
     )
     extra_envs = extra_envs or {}
     conda_in_base: PackageCacheRecord = next((prec for prec in precs if prec.name == "conda"), None)
@@ -496,6 +496,7 @@ def main(info, verbose=True, dry_run=False, conda_exe="conda.exe"):
     transmute_file_type = info.get("transmute_file_type", "")
     extra_envs = info.get("extra_envs", {})
     check_path_spaces = info.get("check_path_spaces", True)
+    base_needs_python = info.get("_win_install_needs_python_exe", False)
 
     if not channel_urls and not channels_remap and not (environment or environment_file):
         sys.exit("Error: at least one entry in 'channels' or 'channels_remap' is required")
@@ -548,6 +549,7 @@ def main(info, verbose=True, dry_run=False, conda_exe="conda.exe"):
             extra_envs,
             check_path_spaces,
             input_dir,
+            base_needs_python,
         )
 
     info["_all_pkg_records"] = pkg_records  # full PackageRecord objects

constructor/main.py

@@ -15,6 +15,7 @@
 import json
 import logging
 import os
+import subprocess
 import sys
 from os.path import abspath, expanduser, isdir, join
 from pathlib import Path
@@ -76,6 +77,18 @@ def get_output_filename(info):
     )
 
 
+def _win_install_needs_python_exe(conda_exe: str) -> bool:
+    results = subprocess.run(
+        [conda_exe, "constructor", "windows", "--help"],
+        capture_output=True,
+        check=False,
+    )
+    # Argparse uses return code 2 if a subcommand does not exist
+    # If the windows subcommand does not exist, python.exe is still
+    # required in the base environment.
+    return results.returncode == 2
+
+
 def main_build(
     dir_path,
     output_dir=".",
@@ -275,6 +288,9 @@ def is_conda_meta_frozen(path_str: str) -> bool:
                 "enable_currentUserHome": "true",
             }
 
+    if osname == "win":
+        info["_win_install_needs_python_exe"] = _win_install_needs_python_exe(info["_conda_exe"])
+
     info["installer_type"] = itypes[0]
     fcp_main(info, verbose=verbose, dry_run=dry_run, conda_exe=conda_exe)
     if dry_run:

constructor/nsis/main.nsi.tmpl

@@ -79,10 +79,12 @@ ${Using:StrFunc} StrStr
 !define ARCH {{ arch }}
 !define PLATFORM {{ installer_platform }}
 !define CONSTRUCTOR_VERSION {{ constructor_version }}
+{%- if has_python %}
 !define PY_VER {{ pyver_components[:2] | join(".") }}
 !define PYVERSION_JUSTDIGITS {{ pyver_components | join("") }}
 !define PYVERSION {{ pyver_components | join(".") }}
 !define PYVERSION_MAJOR {{ pyver_components[0] }}
+{%- endif %}
 !define DEFAULT_PREFIX {{ default_prefix }}
 !define DEFAULT_PREFIX_DOMAIN_USER {{ default_prefix_domain_user }}
 !define DEFAULT_PREFIX_ALL_USERS {{ default_prefix_all_users }}
@@ -304,7 +306,9 @@ FunctionEnd
                 /InstallationType=AllUsers [default: JustMe]$\n\
                 /AddToPath=[0|1] [default: 0]$\n\
                 /KeepPkgCache=[0|1] [default: {{ 1 if keep_pkgs else 0 }}]$\n\
+{%- if has_python %}
                 /RegisterPython=[0|1] [default: AllUsers: 1, JustMe: 0]$\n\
+{%- endif %}
                 /NoRegistry=[0|1] [default: AllUsers: 0, JustMe: 0]$\n\
                 /NoScripts=[0|1] [default: 0]$\n\
                 /NoShortcuts=[0|1] [default: 0]$\n\
@@ -323,9 +327,14 @@ FunctionEnd
                 Install for all users, but don't add to PATH env var:$\n\
                     > $EXEFILE /InstallationType=AllUsers$\n\
                 $\n\
+{%- if has_python %}
                 Install for just me, add to PATH and register as system Python:$\n\
                     > $EXEFILE /RegisterPython=1 /AddToPath=1$\n\
                 $\n\
+{%- endif %}
+                Install for just me and add to PATH:$\n\
+                    > $EXEFILE /AddToPath=1$\n\
+                $\n\
                 Install for just me, with no registry modification (for CI):$\n\
                     > $EXEFILE /NoRegistry=1$\n\
                 $\n\
@@ -349,6 +358,7 @@ FunctionEnd
     ${EndIf}
 
     ClearErrors
+{%- if has_python %}
     ${GetOptions} $ARGV "/RegisterPython=" $ARGV_RegisterPython
     ${IfNot} ${Errors}
         ${If} $ARGV_RegisterPython = "1"
@@ -357,6 +367,7 @@ FunctionEnd
             StrCpy $Ana_RegisterSystemPython_State ${BST_UNCHECKED}
         ${EndIf}
     ${EndIf}
+{%- endif %}
 
     ClearErrors
     ${GetOptions} $ARGV "/KeepPkgCache=" $ARGV_KeepPkgCache
@@ -1142,6 +1153,7 @@ Function OnDirectoryLeave
       UnicodePathTest::UnicodePathTest $INSTDIR
       Pop $R1
 
+{%- if has_python %}
       # Python 3 can be installed in a CP_ACP path until MKL is Unicode capable.
       # (mkl_rt.dll calls LoadLibraryA() to load mkl_intel_thread.dll)
       # Python 2 can only be installed to an ASCII path.
@@ -1159,6 +1171,7 @@ Function OnDirectoryLeave
           abort
 
       valid_path:
+{%- endif %}
 
     Push $R1
     ${IsWritable} $INSTDIR $R1
@@ -1241,6 +1254,50 @@ FunctionEnd
 !insertmacro AbortRetryNSExecWaitMacro ""
 !insertmacro AbortRetryNSExecWaitMacro "un."
 
+{%- set pathname = "$INSTDIR\\condabin" if initialize_conda == "condabin" else "$INSTDIR\\Scripts & Library\\bin" %}
+!macro AddRemovePath add_remove un
+{# python.exe is required if conda-standalone does not support the windows subcommand (<25.11.x) #}
+{%- if needs_python_exe %}
+    ${If} ${add_remove} == "add"
+{%-     if initialize_conda == 'condabin' %}
+        ${Print} "Adding {{ pathname }} PATH..."
+        StrCpy $R0 "addcondabinpath"
+{%-     else %}
+        ${Print} "Adding {{ pathname }} to PATH..."
+        StrCpy $R0 "addpath ${PYVERSION} ${NAME} ${VERSION} ${ARCH}"
+{%- endif %}
+        StrCpy $R1 "Failed to add {{ NAME }} to PATH"
+    ${Else}
+        ${Print} "Running rmpath script..."
+        StrCpy $R0 "rmpath"
+        StrCpy $R1 "Failed to remove {{ NAME }} from PATH"
+    ${EndIf}
+    ${If} ${Silent}
+        push '"$INSTDIR\pythonw.exe" -E -s "$INSTDIR\Lib\_nsis.py" $R0'
+    ${Else}
+        push '"$INSTDIR\python.exe" -E -s "$INSTDIR\Lib\_nsis.py" $R0'
+    ${EndIf}
+    push $R1
+    push 'WithLog'
+    call ${un}AbortRetryNSExecWait
+{%- else %}
+{%- set pathflag = "--condabin" if initialize_conda == "condabin" else "--classic" %}
+    ${If} ${add_remove} == "add"
+        ${Print} "Adding {{ pathname }} to PATH..."
+        StrCpy $R0 "prepend"
+        StrCpy $R1 'Failed to add {{ NAME }} to PATH'
+    ${Else}
+        ${Print} "Removing {{ pathname }} from PATH..."
+        StrCpy $R0 "remove"
+        StrCpy $R1 'Failed to remove {{ NAME }} from PATH'
+    ${EndIf}
+    push '"$INSTDIR\_conda.exe" constructor windows path --$R0=user --prefix "$INSTDIR" {{ pathflag }}'
+    push $R1
+    push 'WithLog'
+    call ${un}AbortRetryNSExecWait
+{%- endif %}
+!macroend
+
 !macro setInstdirPermissions
     # To address CVE-2022-26526.
     # Revoke the write permission on directory "$INSTDIR" for Users. Users are:
@@ -1338,9 +1395,11 @@ Section "Install"
     # for users even during an all-users installation.
     !insertmacro setInstdirPermissions
 
+{% if needs_python_exe %}
     SetOutPath "$INSTDIR\Lib"
     File "{{ NSIS_DIR }}\_nsis.py"
     File "{{ NSIS_DIR }}\_system_path.py"
+{% endif %}
 
 {%- if has_license %}
     SetOutPath "$INSTDIR"
@@ -1533,20 +1592,14 @@ Section "Install"
     ${EndIf}
 
 {% if initialize_conda %}
-    ${If} $Ana_AddToPath_State = ${BST_CHECKED}
-{%-     if initialize_conda == 'condabin' %}
-        ${Print} "Adding $INSTDIR\condabin to PATH..."
-        push '"$INSTDIR\pythonw.exe" -E -s "$INSTDIR\Lib\_nsis.py" addcondabinpath'
-{%-     else %}
-        ${Print} "Adding $INSTDIR\Scripts & Library\bin to PATH..."
-        push '"$INSTDIR\pythonw.exe" -E -s "$INSTDIR\Lib\_nsis.py" addpath ${PYVERSION} ${NAME} ${VERSION} ${ARCH}'
-{%-     endif %}
-        push 'Failed to add {{ NAME }} to PATH'
-        push 'WithLog'
-        call AbortRetryNSExecWait
+    ${If} ${FileExists} "$INSTDIR\.nonadmin"
+        ${If} $Ana_AddToPath_State = ${BST_CHECKED}
+            !insertmacro AddRemovePath "add" ""
+        ${EndIf}
     ${EndIf}
 {%- endif %}
 
+{%- if has_python %}
     # Create registry entries saying this is the system Python
     # (for this version)
     !define PYREG "Software\Python\PythonCore\${PY_VER}"
@@ -1564,6 +1617,7 @@ Section "Install"
         WriteRegStr SHCTX "${PYREG}\PythonPath" \
             "" "$INSTDIR\Lib;$INSTDIR\DLLs"
     ${EndIf}
+{%- endif %}
 
     ${If} $ARGV_NoRegistry == "0"
         # Registry uninstall info
@@ -1594,21 +1648,6 @@ Section "Install"
     ${Print} "Done!"
 SectionEnd
 
-!macro AbortRetryNSExecWaitLibNsisCmd cmd
-    SetDetailsPrint both
-    ${Print} "Running ${cmd} scripts..."
-    SetDetailsPrint listonly
-    ${If} ${Silent}
-        push '"$INSTDIR\pythonw.exe" -E -s "$INSTDIR\Lib\_nsis.py" ${cmd}'
-    ${Else}
-        push '"$INSTDIR\python.exe" -E -s "$INSTDIR\Lib\_nsis.py" ${cmd}'
-    ${EndIf}
-    push "Failed to run ${cmd}"
-    push 'WithLog'
-    call un.AbortRetryNSExecWait
-    SetDetailsPrint both
-!macroend
-
 Section "Uninstall"
     ${LogSet} on
     ${If} ${Silent}
@@ -1660,7 +1699,7 @@ Section "Uninstall"
     System::Call 'kernel32::SetEnvironmentVariable(t,t)i("INSTALLER_NAME", "${NAME}").r0'
     StrCpy $0 ${VERSION}
     ${If} $INSTALLER_VERSION != ""
-	StrCpy $0 $INSTALLER_VERSION
+      StrCpy $0 $INSTALLER_VERSION
     ${EndIf}
     System::Call 'kernel32::SetEnvironmentVariable(t,t)i("INSTALLER_VER", "$0").r0'
     System::Call 'kernel32::SetEnvironmentVariable(t,t)i("INSTALLER_PLAT", "${PLATFORM}").r0'
@@ -1671,16 +1710,18 @@ Section "Uninstall"
         System::Call 'kernel32::SetEnvironmentVariable(t,t)i("INSTALLER_UNATTENDED", "0").r0'
     ${EndIf}
 
-{%- if uninstall_with_conda_exe %}
     ${If} ${FileExists} "$INSTDIR\pkgs\pre_uninstall.bat"
         ${Print} "Running pre_uninstall scripts..."
         push '"$CMD_EXE" /D /C "$INSTDIR\pkgs\pre_uninstall.bat"'
         push "Failed to run pre_uninstall"
         push 'WithLog'
         call un.AbortRetryNSExecWait
     ${EndIf}
-    !insertmacro AbortRetryNSExecWaitLibNsisCmd "rmpath"
+    ${If} ${FileExists} "$INSTDIR\.nonadmin"
+        !insertmacro AddRemovePath "remove" "un."
+    ${EndIf}
 
+{%- if uninstall_with_conda_exe %}
     # Parse arguments
     StrCpy $R0 ""
 
@@ -1727,14 +1768,6 @@ Section "Uninstall"
     call un.AbortRetryNSExecWait
     SetDetailsPrint both
 {%- endfor %}
-    ${If} ${FileExists} "$INSTDIR\pkgs\pre_uninstall.bat"
-        ${Print} "Running pre_uninstall scripts..."
-        push '"$CMD_EXE" /D /C "$INSTDIR\pkgs\pre_uninstall.bat"'
-        push "Failed to run pre_uninstall"
-        push 'WithLog'
-        call un.AbortRetryNSExecWait
-    ${EndIf}
-    !insertmacro AbortRetryNSExecWaitLibNsisCmd "rmpath"
 {%- if has_conda %}
     ${If} ${FileExists} "$INSTDIR\.nonadmin"
         StrCpy $R0 "user"

constructor/osx/run_installation.sh

@@ -119,11 +119,6 @@ find "$PREFIX/pkgs" -type d -empty -exec rmdir {} \; 2>/dev/null || :
 {{ condarc }}
 {%- endfor %}
 
-if ! "$PREFIX/bin/python" -V; then
-    echo "ERROR running Python"
-    exit 1
-fi
-
 # This is not needed for the default install to ~, but if the user changes the
 # install location, the permissions will default to root unless this is done.
 chown -R "${USER}" "$PREFIX"

constructor/winexe.py

@@ -225,16 +225,27 @@ def make_nsi(
 
     # From now on, the items added to variables will NOT be escaped
 
-    py_name, py_version, _ = filename_dist(dists[0]).rsplit("-", 2)
-    assert py_name == "python"
-    variables["pyver_components"] = py_version.split(".")
-
     # These are mostly booleans we use with if-checks
+    default_uninstall_name = "${NAME} ${VERSION}"
+    variables["has_python"] = False
+    for dist in dists:
+        py_name, py_version, _ = filename_dist(dist).rsplit("-", 2)
+        if py_name == "python":
+            variables["has_python"] = True
+            variables["pyver_components"] = py_version.split(".")
+            break
+
+    if variables["has_python"]:
+        variables["register_python"] = info.get("register_python", True)
+        variables["register_python_default"] = info.get("register_python_default", None)
+        default_uninstall_name += " (Python ${PYVERSION} ${ARCH})"
+    else:
+        variables["register_python"] = False
+        variables["register_python_default"] = None
+
     variables.update(ns_platform(info["_platform"]))
     variables["initialize_conda"] = info.get("initialize_conda", "classic")
     variables["initialize_by_default"] = info.get("initialize_by_default", None)
-    variables["register_python"] = info.get("register_python", True)
-    variables["register_python_default"] = info.get("register_python_default", None)
     variables["check_path_length"] = info.get("check_path_length", False)
     variables["check_path_spaces"] = info.get("check_path_spaces", True)
     variables["keep_pkgs"] = info.get("keep_pkgs") or False
@@ -247,6 +258,7 @@ def make_nsi(
     variables["custom_conclusion"] = info.get("conclusion_file", "").endswith(".nsi")
     variables["has_license"] = bool(info.get("license_file"))
     variables["uninstall_with_conda_exe"] = bool(info.get("uninstall_with_conda_exe"))
+    variables["needs_python_exe"] = info.get("_win_install_needs_python_exe", True)
 
     approx_pkgs_size_kb = approx_size_kb(info, "pkgs")
 
@@ -259,9 +271,7 @@ def make_nsi(
     variables["SETUP_ENVS"] = setup_envs_commands(info, dir_path)
     variables["WRITE_CONDARC"] = list(add_condarc(info))
     variables["SIZE"] = approx_pkgs_size_kb
-    variables["UNINSTALL_NAME"] = info.get(
-        "uninstall_name", "${NAME} ${VERSION} (Python ${PYVERSION} ${ARCH})"
-    )
+    variables["UNINSTALL_NAME"] = info.get("uninstall_name", default_uninstall_name)
     variables["EXTRA_FILES"] = get_extra_files(extra_files, dir_path)
     variables["SCRIPT_ENV_VARIABLES"] = {
         key: win_str_esc(val) for key, val in info.get("script_env_variables", {}).items()